I am training a CNN model which takes input of 128x128x3 color images and is trained to predict the coordinates of 4 landmarks on it (i.e, there are 2 * 4 = 8 values to be predicted if we count x and y coordinates separately. All of the coordinate values are scaled in [-1, 1] Following is my model class: class LandmarkLocalizerCNN:      def __init__(self, input_shape, landmark_point_count):         self.input_shape = input_shape         self.landmark_point_count = landmark_point_count      def first_level_cnn(self):         model = models.Sequential()          model.add(layers.Conv2D(8, (5, 5), padding = 'same',activation = 'relu', input_shape = self.input_shape))         model.add(layers.Conv2D(8, (5, 5), padding = 'same',activation = 'relu', input_shape = self.input_shape))         model.add(layers.Conv2D(16, (5, 5), padding = 'same',activation = 'relu', input_shape = self.input_shape))         model.add(layers.Conv2D(16, (5, 5), padding = 'same',activation = 'relu', input_shape = self.input_shape))         model.add(layers.MaxPooling2D((2, 2)))          model.add(layers.Conv2D(32, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.Conv2D(32, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.Conv2D(32, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.Conv2D(32, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.MaxPooling2D((2, 2)))          model.add(layers.Conv2D(64, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.Conv2D(64, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.Conv2D(64, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.Conv2D(64, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.MaxPooling2D((2, 2)))           model.add(layers.Conv2D(128, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.Conv2D(128, (3, 3), padding = 'same', activation = 'relu'))         model.add(layers.MaxPooling2D((2, 2)))          model.add(layers.Flatten())         model.add(layers.Dense(64, activation = 'relu'))         model.add(layers.Dense(32, activation = 'relu'))         model.add(layers.Dropout(0.2))         model.add(layers.Dense(16, activation = 'relu'))         model.add(layers.Dense(16, activation = 'relu'))         model.add(layers.Dropout(0.2))         model.add(layers.Dense(16, activation = 'relu'))         model.add(layers.Dense(16, activation = 'relu'))         model.add(layers.Dense(2 * self.landmark_point_count))          return model  And here is the created model: first_level_cnn_model = LandmarkLocalizerCNN(input_shape = (128, 128, 3), landmark_point_count = 4).first_level_cnn()  After training for 375 steps I got the metrics as following:  Here are some of my observations:  If I remove dropouts the training accuracy goes higher (around 0.9) quickly even with lesser number of layers. With dropout layers training accuracy doesn't go that higher but in either cases validation accuracy hardly crosses 0.6 In this current architecture the graph shows fluctuations in both training and validation plots with some strange behaviors. For training, the accuracy and loss seems to be negatively correlated but for validation they seem to be positively correlated. But finally both of them saturated and no more improvements.  So what the main problem my model is suffering from. I tried increasing and decreasing the number of layers and also adding or removing dropouts but they only help changing the training accuracy. But the validation accuracy hardly crosses 0.6 whatever I do, so how can I make my model to perform better in unknown cases?

I'm training a neural network and the training loss decreases, but the validation loss doesn't, or it decreases much less than what I would expect, based on references or experiments with very similar architectures and data. How can I fix this?    As for question        to which this question is inspired, the question is intentionally left general so that other questions about how to reduce the generalization error of a neural network down to a level which has been proved to be attainable, can be closed as duplicates of this one.  See also dedicated thread on Meta:


Use an indented contour and residues to establish the Cauchy principal   value of $\int_{-\infty}^{\infty}\frac{\sin x}{x}$ using complex   integration.   I see that breaking this up into $\int_{C_R} + \int_{-R}^{-r} + \int_{-C_r} + \int _{-r}^{R}$ (where $-C_r$ is the upper hemispherical contour about $0$ and under $C_R$),  and taking the limit as $r \rightarrow 0 \text{ and } R \rightarrow \infty$ would the be ideal method, but I don't see how $\int_{C_R} \rightarrow 0$.  Even if I alter $\int_{-\infty}^{\infty}\frac{\sin x}{x}$ to $\int_{-\infty}^{\infty}\frac{e^{iz}}{x}$, I'm still left with the fact that the denominator is not $\ge 2 + $the degree of the numerator.  Am I missing something here or is there a better way to solve this?

This refers back to $\int_{-\infty}^\infty \frac{\sin x}{x} \mathrm{d}x = \frac\pi2$ already posted. How do I arrive at $\frac\pi2$ using the residue theorem? I'm at the following point: $$\int \frac{e^{iz}}{z} - \int \frac{e^{iz}}{z},$$ and I would appreciate any help.


Im trying to create a layout that will show the received location updates in the text view, but i keep getting this error, what am i doing wrong?   Help would be appreciated, thanks in advance!  Here is the error:      E/AndroidRuntime: FATAL EXCEPTION: main                    Process: com.example.defro.app, PID: 7731                    java.lang.NullPointerException: Attempt to invoke virtual >method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null >object reference                         at com.example.defro.app.MainActivity$1.onLocationChanged(MainActivity.java:29)`   Row 29 is:   txtLoc.setText(String.valueOf(iaLocation.getLongitude() + ", " + iaLocation.getLatitude()));  Main_Activity:  public class MainActivity extends AppCompatActivity {  IALocationManager mLocationManager; IALocationListener mLocationListener = new IALocationListener() {     @Override     public void onLocationChanged(IALocation iaLocation) {         TextView txtLoc = (TextView) findViewById(R.id.textView);         txtLoc.setText(String.valueOf(iaLocation.getLongitude() + ", " + iaLocation.getLatitude()));      }      @Override     public void onStatusChanged(String s, int i, Bundle bundle) {      }  }; private final int CODE_PERMISSIONS = 1;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);      mLocationManager = IALocationManager.create(this);       String[] neededPermissions = {             Manifest.permission.CHANGE_WIFI_STATE,             Manifest.permission.ACCESS_WIFI_STATE,             Manifest.permission.ACCESS_COARSE_LOCATION,             Manifest.permission.BLUETOOTH,             Manifest.permission.BLUETOOTH_ADMIN        };     ActivityCompat.requestPermissions(this, neededPermissions, CODE_PERMISSIONS);   } public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {     super.onRequestPermissionsResult(requestCode, permissions, grantResults);      //Handle if any of the permissions are denied, in grantResults }   protected void onResume() {     super.onResume();     mLocationManager.requestLocationUpdates(IALocationRequest.create(), mLocationListener);  }  protected void onPause() {     mLocationManager.removeLocationUpdates(mLocationListener);     super.onPause(); }  protected void onDestroy() {     mLocationManager.destroy();    super.onDestroy(); }   }  content_main.xml:  <TextView     android:layout_width="wrap_content"     android:layout_height="23dp"     android:text="Lat, Long"     app:layout_constraintBottom_toBottomOf="parent"     app:layout_constraintHorizontal_bias="0.051"     app:layout_constraintLeft_toLeftOf="parent"     app:layout_constraintRight_toRightOf="parent"     app:layout_constraintTop_toTopOf="parent"     app:layout_constraintVertical_bias="0.032" />

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I have multiple vhosts (apache) and these are all just http. Recently I added an https vhost and found that using https on any of these domains would redirect to the ssl site.  For example, there's:    and the ssl site:    So the issue is that if someone would go to https//example.com it would redirect to https//example4.com  I tried some redirects in the vhosts but that didn't appear to work. Any help would be greatly appreciated. Thanks.

I have the following in my httpd.conf file  NameVirtualHost *:80  <IfModule mod_vhost_alias.c>   <VirtualHost *:80>     ServerAlias *     UseCanonicalName Off     LogFormat "%V %h %l %u %t \"%r\" %s %b" vcommon     CustomLog /var/log/httpd/access_log vcommon     VirtualDocumentRoot /web-data/vhosts/%0/httpdocs     VirtualScriptAlias  /web-data/vhosts/%0/httpdocs   </VirtualHost> </IfModule>   This works great for dynamic hosting. However, I can't figure out how to make https requests work the same way. What do I need to add to this so that https and http for the same domain request get sent to the same folder?


Given $m$ i.i.d. Bernoulli( $\theta$ ) r.v.s $X_{1}, X_{2}, \ldots, X_{m},$ l'm interested in finding estimator of $(1-\theta)^{1 / k},$ when $k$ is a positive integer. I am considering the following options:   $\textbf{MLE}$  Optimizing the likelihood function implies $\hat{\theta}=\sum_{i=1}^{m}\frac{X_i}{m}$. Thus, using theinvariance property, the required MLE estimator is $(1-\sum_{i=1}^{m}\frac{X_i}{m})^{1 / k}.$  $\textbf{MVUE}$  It has been established  that UMVUE does not exist unless we have an infinite number of samples from the Bernoulli distribution.   But then, I am thinking of a truncated version of the UMVUE obtained by using a finite number of terms in the binomial expansion. I know this is going to be biased and not of minimum variance.   EDIT: How I am constructing the truncated estimator is as follows: We know from binomial series (general version)   $ \begin{aligned} (1-\theta)^{\alpha} &=\sum_{k=0}^{\infty}\left(\begin{array}{l} \alpha \\ k \end{array}\right) (-\theta)^{k} \\ &=1+\alpha (-\theta)+\frac{\alpha(\alpha-1)}{2 !} (-\theta)^{2}+\cdots \end{aligned}$  Now, I will use UMVUE for $\theta^{k}$ as described [here] (). Now I can truncate this sum for a finite number of terms and use that as an approximate version.   How does the performance of this truncated UMVUE estimator compare to MLE? Are there any known theoretical guarantees about this truncated estimator? I am assuming this truncated estimator should perform better than MLE in terms of variance. Could someone throw some more light on this? Any tips or guidelines are appreciated.   Also, are there any other estimators that are useful in a practical setting. I know there are a lot of other estimators, but I am asking from a practical point of view. Something which is better than MLE in practice?

Given $m$ i.i.d. Bernoulli( $\theta$ ) r.v.s $X_{1}, X_{2}, \ldots, X_{m},$ I'm interested in finding the UMVUE of $(1-\theta)^{1/k}$, when $k$ is a positive integer. .  I know $\sum X_{i}$ is a sufficient statistic by the Factorization Theorem, but I'm having trouble proceeding from there. If I can find an unbiased function of the sufficient statistic the problem is solved by the Rao-Blackwell theorem.


I tried to recover my home folder, it was stored on it's own partition and I removed it by a mistake but no problem, I had a back up. Although I wanted to try to restore it so I used dd to create an image. By using sudo tsk_recover -e /xxx/image.img /xxx/tsk/I got 1000 files back but with "Disk Drill" on Windows I got the whole 40.000 files in great quality. My question is what did I wrong or is there something equal to Disk Drill on Linux?

Are there any tools, methods, incantations to recover recently deleted files on Ubuntu?  If it makes any difference, I want to recover a  2.x database file. But would be better to have a method/tool that works on any kind of file.


The Mann-Whitney U test or the Wilcoxon Rank Sum test is sensitive to unequal variances. Is there an equation that adjusts the standard deviation of this statistic, much like in the Welch-corrected t-test for independent samples?

I am confused on what I have read about the Mann whitney test. We are testing whether our actual data is the same as our projected data. We had been using the t-test until we realized the data might not be normal and we are using ~12 observations per sample. Therefore I started using the Mann Whitney test.   I have read some places that the test is not appropriate unless the variances are equal, and other places have said you can still use it if you don't care if the shapes are identical.   So do I need to test each sample against the other to see if the variances are equal? Do the interpretation of the results differ if the variances are not equal?


Within the last week or so, I noticed Stack Overflow no longer sorts by number of votes. Aside from the answer with the most votes, which does seem to come first, the rest of the answers seem to be in a random order. What's going on here?  ex:   Notice the answers here have 195, then 3, then 29 votes. The 3 should come after the 29!  There's also a 17, 40, and 28, in that order, far after the 29 here too. what's going on!? And this isn't just this one answer, this is happening with nearly every answer I've looked at over the past week or so.  It makes finding the top few best answers quickly really difficult.

Recently, my answers are showing at the bottom of the page, even though I got good scores on those answers.       How do I change this back?


I am tracing ancestors born in the late 18th through mid 19th century from a village which at the time was in western Hungary. Following the end of WWI, the area was transferred to Austria and the name of the village changed. Hungary Catholic Church records give the Hungarian name/location, but online genealogies cite the Austrian name/location (which did not exist at the time of the individuals' birth). Which is correct (or more appropriate)?

When I am documenting records, do I use the name of a city or country as it is called today or as it was in the year an ancestor was there?  Related to:


I've seen this horror movie in early to mid-2000s, but the quality wasn't really good, so I suppose the movie could've been older.   The main theme is some kind of alien invasion, where aliens are little slugs which infect people through the mouth.   The one thing I remember really good: the scene where college students are playing American football, one of the players gets knocked off by the infected one and while the infected one stands above knocked down on all fours, the slug falls off from his mouth to the uninfected.  I've done some research and it's not likely one of these movies, as I couldn't find the football scene there:

I need to find a film that I watched in 2000-2010. I remember the invasion started in a high school football stadium. A group of teenagers figure it out and run home. People look normal but get mind controlled. They know the city got attacked and the thing to defend themselves is a drug(or a substance) they usually use. I also remember the group has about 5-7 people. They try to escape the city but eventually get discovered. At the end of the day, the group only had 2 people left and end up going to the stadium. They hide and figure out there is a queen-like creature in the stadium and try to use the last dose to kill it. Then one goes out and later comes back to their hideout but the other isn't sure that he(she) isn't controlled. That is all the plot I can remember. Please help me find it.


My question is multifaceted.  So I'll start by asking my question and then explain what has caused me to ask this question.  How can I calculate the coefficient of determination for a linear regression with a defined y-intercept?  The y-variable is the dependent variable and the x-variable is the independent variable.  For example, the y-intercept would be set equal to 0 when the x-variable is 0.  The equation of the line would be y = mx + b and b = 0.  My question came about when I was trying to plot experimentally measured fluid flow data.  I am plotting my data in a way that compares the data to , a phenomenological model for fluid flow through porous media that says for certain conditions the volumetric flow rate is proportional to pressure gradient.  Below is my dataset and my plot of the data.  x: {54, 25, 14, 7}  y: {458, 295, 204, 118}  Note*: For simplicity here, I rounded my dataset numbers to the nearest whole number.    I plotted the data in Microsoft Excel and applied a linear trendline with a the y-intercept set to zero.  I applied the trendline this way because based on Darcy's Law the y-variable (volumetric flow rate) should be zero when the x-variable (pressure gradient) is equal to zero.  Displaying the coefficient of determination on the plot, Excel shows it to be, R2 = 0.779.  When I use Microsoft Excel's  I get a coefficient of determination, R2 = 0.9602, as seen in the image below.      For the LINEST function I used: =LINEST(known y's, known x's, FALSE, TRUE), where in the third argument I used "FALSE" to set the y-intercept, b, equal to zero.  There is a discrepancy between the two coefficients of determination given by Excel, 0.779 versus 0.9602.  Furthermore, if I tell Excel's LINEST function to calculate the regression without a set intercept, e.g. := LINEST(known y's, known x's, TRUE, TRUE), where the third argument I used "TRUE" to, as Excel claims, "to calculate b normally".  I get a coefficient of determination, R2 = 0.9742, as seen in the image below.    This R2 value matches the graphical output Excel provides for the R2 value if I format the plot's trendline to not have a set y-intercept, as seen in the image below.    Since Excel calculated the same R2 value for a trendline without a set y-intercept, this leads me to believe there is something erroneous with the LINEST function when tryint to set y-intercept to zero (using "FALSE" as the third argument).  I have read multiple times that one should really not use Excel for any but the simplest of statistics, and sometimes not even then because Excel has a bunch of "gotchyas".  If I want to calculate the coefficient of determination by hand, how can I do it?  Further, what is going on with Excel, why is it calculating different values?  I am using Excel 2010.

In a simple linear model with a single explanatory variable,  $\alpha_i = \beta_0 + \beta_1 \delta_i + \epsilon_i$  I find that removing the intercept term improves the fit greatly (value of $R^2$ goes from 0.3 to 0.9). However, the intercept term appears to be statistically significant.  With intercept:   Call: lm(formula = alpha ~ delta, data = cf)  Residuals:      Min       1Q   Median       3Q      Max  -0.72138 -0.15619 -0.03744  0.14189  0.70305   Coefficients:             Estimate Std. Error t value Pr(>|t|)     (Intercept)  0.48408    0.05397    8.97   <2e-16 *** delta        0.46112    0.04595   10.04   <2e-16 *** --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   Residual standard error: 0.2435 on 218 degrees of freedom Multiple R-squared: 0.316,    Adjusted R-squared: 0.3129  F-statistic: 100.7 on 1 and 218 DF,  p-value: < 2.2e-16    Without intercept:   Call: lm(formula = alpha ~ 0 + delta, data = cf)  Residuals:      Min       1Q   Median       3Q      Max  -0.92474 -0.15021  0.05114  0.21078  0.85480   Coefficients:       Estimate Std. Error t value Pr(>|t|)     delta  0.85374    0.01632   52.33   <2e-16 *** --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   Residual standard error: 0.2842 on 219 degrees of freedom Multiple R-squared: 0.9259,   Adjusted R-squared: 0.9256  F-statistic:  2738 on 1 and 219 DF,  p-value: < 2.2e-16    How would you interpret these results? Should an intercept term be included in the model or not?  Edit  Here's the residual sums of squares:  RSS(with intercept) = 12.92305 RSS(without intercept) = 17.69277


For the past year or so, my Lenovo W530 laptop has intermittently decided that I'm holding down the 'z' key. The key was never physically stuck; indeed, I could double the rate at which it typed z's by holding down the key! I always had to reboot to fix it, but the problem didn't crop up too frequently.  As of this evening, however, it has been constantly malfunctioning. It starts spamming z's within seconds of logging in - there is a bit of a delay before the horde of z begins.  In Windows 7, I can temporarily stop it by switching users, but it begins again before long. The issue also occurs in Ubuntu Trusty and a live-booted copy of Debian, so it's probably not caused by malware or something similar.  The issue does not occur in the BIOS menu.  I've combed through forum posts about stuck keys and whatnot, but I still haven't the foggiest idea about what's going on. Does anyone know what might be causing this?

The keyboard on my laptop seems to be typing by itself:   It sometimes types characters like 134, whether by itself or when I hit certain keys. Repeating characters may appear unexpectedly. The system volume may change by itself, or windows like the Print dialog or Web browser may appear.   This can happen without any input or as I type, and may occur more often when certain keys are pressed. Sometimes, the keyboard fails to respond altogether. This is happening regardless of the software involved.  Is there a ghost in my keyboard—is my keyboard broken?  A sample of text from the keyboard might look like this (normal QWERTY...ASDF...ZXC... sequence is expected):   QWERTYUIOPASDF)(G@*HKLZXCVBN QWERTYIOPASDFGL!#ZXCVB13 QWERTYUIOPASDFGHJKLZXCVB!#N qwertyu41iopasdf19g13h28j113k4113zxcvb4n qwerty4u1iopasdf0g7h1jklzxcvb13m qwert13uuuuuuuuuuuuuuuiopasdf87091134ghhhhhhhhhhhhhhhhhhhhhhh13jk13zxcvb14      This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.


When using SO's code blocks, can you control how syntax highlighting is performed? Many times, I've pasted (for example)  into an SO answer, and the syntax highlighting has been completely unrelated. Is there any way to turn it off, or to change the language used?

I noticed that sometimes my code gets highlighted in different colors when rendered.   What is syntax highlighting? How does it work? Why isn't my code being highlighted correctly? How do I report a bug or request a new language? How do I use syntax highlighting? What languages are currently available on Stack Exchange?


I currently have Centos 7 installed on EC2 with the following: Apache Php Mysql Iptables Firewalld    Apache running     Redirecting to /bin/systemctl status  httpd.service ● httpd.service -   The Apache HTTP Server    Loaded: loaded   (/usr/lib/systemd/system/httpd.service; enabled; vendor preset:   disabled)    Active: active (running) since di 2016-01-26 01:18:52   UTC; 16min ago        Docs: man:httpd(8)              man:apachectl(8)   Process: 4387 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=0/SUCCESS)  Main PID: 4392 (httpd)   Status: "Total requests: 0; Current requests/sec: 0; Current traffic:    0 B/sec"    CGroup: /system.slice/httpd.service              ├─4392 /usr/sbin/httpd -DFOREGROUND              ├─4393 /usr/sbin/httpd -DFOREGROUND              ├─4394 /usr/sbin/httpd -DFOREGROUND              ├─4395 /usr/sbin/httpd -DFOREGROUND              ├─4396 /usr/sbin/httpd -DFOREGROUND              └─4397 /usr/sbin/httpd -DFOREGROUND   FIREWALLD Disabled:     ● firewalld.service - firewalld - dynamic firewall daemon    Loaded:   loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor   preset: enabled)    Active: inactive (dead)   IPTABLES ENABLED     ● iptables.service - IPv4 firewall with iptables    Loaded: loaded   (/usr/lib/systemd/system/iptables.service; enabled; vendor preset:   disabled)    Active: active (exited) since di 2016-01-26 01:14:23 UTC;   2min 27s ago   Process: 4317   ExecStart=/usr/libexec/iptables/iptables.init start (code=exited,   status=0/SUCCESS)  Main PID: 4317 (code=exited, status=0/SUCCESS)   IPTABLES RULES     Chain INPUT (policy ACCEPT) target     prot opt source   destination   ACCEPT     all  --  0.0.0.0/0     0.0.0.0/0            state   RELATED,ESTABLISHED       ACCEPT     tcp  --   0.0.0.0/0            0.0.0.0/0            tcp dpt:80       ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp   dpt:22       ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0      Chain FORWARD (policy ACCEPT) target     prot opt source   destination               Chain OUTPUT (policy ACCEPT) target     prot opt source   destination   Iptables sysconfig file:     *filter       :INPUT ACCEPT [0:0]       :FORWARD ACCEPT [0:0]       :OUTPUT ACCEPT [214:43782]      -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT      -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT      -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT      -A INPUT -i lo -j ACCEPT COMMIT   Selinux:     getenforce: Disabled   My virtualhosts are correct, pass the configtest and all.. So with these settings, I still receive nothing on my webserver. Nothing in my access logs or error logs.. What I am overseeing in my configuration?  Thanks in advance.

I set up a micro instance (Ubuntu, 32 bit) and assigned an elastic IP (23.23.245.104)  Public DNS: ec2-23-23-245-104.compute-1.amazonaws.com  I successfully ssh'ed to the machine and installed nginx.  Then I edited the server_name attribute in nginx's config file (/etc/nginx/sites-available/default)  server_name ec2-23-23-245-104.compute-1.amazonaws.com;   Restarted nginx and hit  but got a "could not connect" error.  What did I forget to do?  Thanks


I'm having an issue with a loop cut in the image below. The face I'm having the issue is the following:    For other hand my intention is to have the part in blue in the below image totally straight and not curved:    This is the reason I want to loop cut the entire perimeter and move in the Z axis all the edges to make it straight.  I already cleaned up duplicated vertex and the normals are alright but I don't know why is not loop cutting all.

Alright so I've seen some postings about loop cuts and done some research. I am very new to blender and modeling overall. I am trying to loop cut this concrete barrier. Now I'm following a tutorial and kind of did my own thing in some areas. I cleaned it up following some instructions in another answer here on stack exchange.  I can't for the life of me figure out why I can loop cut around the whole bottom:   ...but not the whole middle:   I see this marked as answered by another question. That question refers to ngons and inside faces. Now once again I'm totally new to this. I looked on the inside. I don't believe I have inside faces or any ngons by the terms I've read online in my research.  Here is a wireframe picture and the inside view:     Maybe I'm missing something the answers on other posts are saying. If so and you know what it is I'd be very appreciative of what it is.


I was tired of my dual boot setup and wanted to get rid of Ubuntu for the time being since I rarely used it. Being the smart guy I am, I simply deleted the partition it was on and added it back to my HDD. Next day I boot my computer up and I'm in grub rescue.   I have the installation disk for windows but I don't have an optical drive on my pc so I tried to solve the problem via grub rescue and Ubuntu Live CD. I repaired grub (sort of) so it booted to a black grub> terminal. (I'm used to purple screen to select OS.) Had no luck with that so I caved and purchased and external optical drive and ran bootrec /FixMbr from the installation disk to fix the booting issues.   Now my question is, with the partition deleted, can I check if all traces of Ubuntu are off my computer?

I installed Ubuntu (twice actually) onto the same drive. I wanted to 'try again' since one of them didn't install correctly and the other installed differently, but it worked.   I was getting frustrated with the GRUB menu because it was really sloppy (There were two Windows options - one with the Windows bootloader to go into Ubuntu, and two different versions of Ubuntu from the first install for some reason and memtest, etc.).  In my attempts at getting rid Ubuntu to do a fresh installation, I went ahead and deleted the partitions that weren't swap or main via Windows 7. As I said, I am a noob.  Now, even though I though I completely got rid of Ubuntu, including the GRUB menu, when I boot my PC I am brought directly to GRUB Rescue. And from what I've found from other forums, GRUB rescue isn't even completely functional for me (it doesn't recognize any commands that it should support besides ls. It also returns unknown filesystem for any partition I try to view or boot.)  Is there any way that I can boot straight into Windows? I fear I may have gone about deleting those partitions in the wrong way. If so, what are my options?


I'm trying to prove that  $$\sum_{k=0}^n {n \choose k} (-1)^k \frac{1}{k+1} = \frac{1}{n+1}$$  So far I've tried induction (which doesn't really work at all), using well known facts such as  $$\sum_{k=0}^n {n \choose k} (-1)^k = 0$$  and trying to apply identities like  $${n \choose k} = {n-1 \choose k-1} + {n-1 \choose k}$$  Would anyone be able to point me towards the right method? Should I be looking to apply an identity or is there a method I'm missing?

Other than the general inductive method,how could we show that $$\sum_{r=0}^n \frac{(-1)^r}{r+1}\binom{n}{r} = \frac1{n+1}$$  Apart from induction, I tried with  to check the validity, but I can't think of an easy (manual) alternative.  Please suggest an intuitive/easy method.


I offered a bounty to a question and there is a good answer. If I give the bounty to that answer, could I change the bounty to another better answer within the seven days that the bounty is offered?

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


On the 6th turn, the Babylon player builds their second stage wonder. Their last card in hand requires a Cloth.  Babylon's neighbor built a Loom on their 6th turn. Can the Babylon player, on their 7th turn, purchase Cloth from that neighbor?  This is not a duplicate question. My question specifically asks whether the Babylon player may benefit from the 6th card build by Babylon's neighbors for the 7th card and 7th card only.  All other answers talk about the 7th card benefiting from the 6th card of the Babylon player, or whether the usage state of Babylon's and neighbors resources may be reset for the 7th card's use.  (Also, can does the Babylon player receive gold earned from neighbors between their 6th and 7th card?)

Scenario:   Player is using Babylon (side B)  2nd wonder has been completed (allows playing last card of each age instead of discarding) Player has a Mine in play (can produce either Stone or Ore) Player has no other way to produce Stone or Ore and no money to purchase from a neighbor It is the 6th turn of Age I Player has a Barracks and a Baths in hand (resource cost of one Ore and one Stone, respectively)   Can the player play both Barracks and Baths?  The 2nd wonder allows the player to play both the Barracks and Baths (assuming he can pay the costs), instead of having to discard one. The Mine can produce both resources, but the rules regarding cards that can produce more than one type of resource state:     the player can use one OR the other resource to build a structure (or a wonder phase) but NOT both in a given turn.   Both cards would be played in the 6th turn, so it would seem that the player cannot use the Mine to pay the cost of each card. However, is the limitation on using resource cards only once per turn really meant to be once per construction?  This question really applies to any resource producing card, not just the multi-resource producing cards. It was just simpler to explain this way, and the issue is more fuzzy due to the specific prohibition on multi-resouce producing cards being used more than once in a turn.


: The book presents a one-sided view of history.   I'm confused. I thought that it should be an one-sided view of history. Could you please explain this case to me?   I know that the article is for the noun (view) not for the adjective (one-sided) but I was told that even if a word starts with a consent which sounds like a vowel, it should be preceded with "an" not "a". So I always thought the grammar rule is based on a vocal need. What I mean by this is that it is easier for Native English speakers to say "an" one-sided instead of "a" one-sided.

I was writing a text when I came to say 'a union', then it struck me that I need to change the 'a' to 'an'. But for some reason, 'an union' didn't sound right.   Why doesn't it work? Is it because its a mass noun, instead of a regular noun?


Steam was running fine for a few months, but recently it didn't start up, so I tried re-installing it and it still doesn't start!  Is it My PID and how do I check if My PID is running?

When I try to start Steam nothing happens. Reinstall doesn't help.  $ steam Running Steam on ubuntu 13.04 64-bit STEAM_RUNTIME is enabled automatically Installing breakpad exception handler for appid(steam)/version(1378500910_client) Installing breakpad exception handler for appid(steam)/version(1378500910_client) Installing breakpad exception handler for appid(steam)/version(1378500910_client) unlinked 0 orphaned pipes removing stale semaphore last operated on by process 7278 with name 0eBlobRegistryMutex_DC7EBB4AEA41D3C6C74E5EFFD6757CEC removing stale semaphore last operated on by process 7278 with name 0eBlobRegistrySignal_DC7EBB4AEA41D3C6C74E5EFFD6757CEC removing stale semaphore last operated on by process 7278 with name 0emSteamEngineInstance removing stale semaphore last operated on by process 7278 with name 0eSteamEngineLock Gtk-Message: Failed to load module "overlay-scrollbar" Installing breakpad exception handler for appid(steam)/version(1378500910_client) [0913/182910:WARNING:proxy_service.cc(958)] PAC support disabled because there is no system implementation   How to fix it?


It shouldn't, but I am blanking on a counterexample.  ETA: Note that the $t$ is shared on both sides - which differentiates this from . Similarly $F_{X,Y}(x,y)=F_X(x)F_Y(y)$ implies independence, but $F_{X,Y}(t,t)=F_X(t)F_Y(t)$ doesn't.

This is solely a reference request. I have heard a few versions of the following theorem:     If the joint moment generating function $\mathbb{E}[e^{uX+vY}] = \mathbb{E}[e^{uX}]\mathbb{E}[e^{vY}]$ whenever the expectations are finite, then $X,Y$ are independent.   And there is a similar version for characteristic functions. Could anyone provide me a serious reference which proves one or both of these theorems?


Find the value of the following (using an epsilon proof or basic limit properties (no L'hospital)):  $$\lim_{x\to\infty}\left( \sqrt{(x+a)(x+b)}-x \right)\forall a,b\in\mathbb{R}$$  I've tried rewriting it in several ways, but I don't seem to bet getting very far; I always end up with something in indeterminate form.  How can you prove the value of this?  Any hints?

Hi I have a question regarding finding the values of limit for the following question.  Let $a, b \in \mathbb R$. Find the limit $$\lim_{x\to+\infty}\left(\sqrt{(x+a)(x+b)}-x\right)$$


I remember on 16.04 I had to change settings so that windows could be completely full-screen. On 18.04, I can't figure it out. The menu bar on the left is always visible. I am looking for "zen-mode" where a given application can be completely full-screen, anyone know how to do that in 18.04?

I have two questions :  First, I wanted to hide Ubuntu’s side-bar, so I set the settings in appearance to 'autohide'. The side bar did indeed disappear but when I roll over the left side, the side bar don't appear again. So, I am using a virtual box. Can it explain the fact that this bar doesn't show again when it is set to autohide.   Second, assuming I wouldn't be able to come over the problem, I pined to the dock every element of the sidebar, except the dash home. Is it possible either to pin it in the dock or to launch it from the terminal ?


After searching favorited question everywhere I am unable to find FAVOURITE section in the app. Please do something for this.

I haven't been able to find my favorite questions in the official Stack Exchange Android app.  Looking at my accounts page gives nothing on them.


I bought a Wireless USB Adapter TL-WN823N v2.0 for raspberrypi, but i cant find the corrent driver for it, The output of lsusb is:  0bda:a192 Realtek Semiconductor Corp  i have searched a lot about 0bda:a192, but cant get any information about it.Any help?  Thanks

I'm trying to install wifi drivers for a particular mini wifi card i bought. The output of lsusb is:  0bda:f179 Realtek Semiconductor Corp   I've searched everywhere for drivers, but could not find anything. Any help?  Thanks


Recently, I submitted a paper to a journal published by Elsevier. The "Elsevier Journal Finder" feature suggested this particular journal in #3 out of a total of 5 suggestions. A while ago, I had also published a work in the same journal, which was of the same topic (satellite retrievals) that I was trying to submit now. However, for the recent submission, the editor decided that the paper is not topical to the journal and suggested to submit in a mathematical journal. Although there are some mathematical applications in this paper, they are not new, has been known for over 20 years, and was only applied towards satellite retrievals. I am a bit puzzled. Any advice will be appreciated.

I submitted a manuscript last year to an IEEE journal, and the paper was accepted for publication. I recently submitted a new manuscript to the same journal, but, this time, the paper was rejected, and I was told that I should submit to another journal since my paper was not within the journal's scope. The two papers both target similar applications. Furthermore, the second paper uses some work in the first paper, making substantial improvements at solving a much more difficult problem. Based on the reviewer's comments (and my own personal assessment), I do not believe that the work presented in the second paper was "incremental" in nature. Far from it. Two of the three reviewers gave positive reviews. The third reviewer, however, mentioned the "outside of journal's scope" issue and the associate editor and editor-in-chief both sided with the 3rd reviewer, and the paper was stopped dead in its tracks.  I'm scratching my head trying to come to terms with how in the world my first paper could be accepted by this journal, but the second paper focused on the same application space and achieving substantial improvements on a much more difficult problem (backed up with measured results) could be rejected. Any ideas?


I'm trying to use the next array's elements to replace some strings in a file:  declare -a replacements=($name, $description, $date, $keywords)   By using the search terms in this array:  declare -a searchs=("a.name", "a.description", "a.date", "a.keywords")   The problem is that some variables (description, for example) have whitespaces in them:  declare description = "My name is Jonah"   Which casuses a weird behaviour on the next piece of code:  for ((i = 0; i < ${#searchs[@]}; i++)) do     sed -i -e "s/${searchs[$i]}/${replacements[$i]}/g" "./${directory}/data.txt" done   The for loops uses every word in the string as a replacement instead of the whole string.  Is there a way to fix this error? Thanks in advance!

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


I'm trying to mount the EFI Partition from Disk Management but all the options for the EFI partition are greyed out, so I can't do anything..  here's a screenshot from the problem :

Here is what I do:   restart machine with Windows 8.1 determine "EFI System" partition with the Disk Management utility run command prompt as administrator type diskpart type select disk 0 then select partition 2 then assign open windows explorer windows+e refresh if the drive is not showing F5 try to open drive by double clicking   What I expected to happen:  I can at least look at my EFI partition files.  What happened:    after clicking continue    after clicking "security tab" link, no security tab    What do I need to do to access my EFI partition on Windows 8.1?


I am trying to figure out a way where I can find all the invalid characters in an XML.  According to  these are the valid characters in an XML:  #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]   Converting it to decimal:  9 10 13 32-55295 57344-65533 65536-1114111   are the valid xml characters.  I am trying to search in notepad++ using the appropriate regular expression for the invalid characters.  A snippet from my XML:          <custom-attribute attribute-id="isContendFeed">fal &#11; se</custom-attribute>         <custom-attribute attribute-id="pageNoFollow">fal &#3; se</custom-attribute>         <custom-attribute attribute-id="pageNoIndex">fal &#13; se</custom-attribute>         <custom-attribute attribute-id="rrRecommendable">false</custom-attribute>   From the above example I want that my regular expression finds &#11; and  &#3; for me because these are not allowed in an XML.  I am not able to construct the regular expression for this.  The regular expression I made for the numeric ranges:  32-55295 : (3[2-9]|[4-9][0-9]|[1-9][0-9]{2,3}|[1-4][0-9]{4}|5[0-4][0-9]{3}|55[01][0-9]{2}|552[0-8][0-9]|5529[0-5]) 57344-65533 : (5734[4-9]|573[5-9][0-9]|57[4-9][0-9]{2}|5[89][0-9]{3}|6[0-4][0-9]{3}|65[0-4][0-9]{2}|655[0-2][0-9]|6553[0-3]) 65536-1114111 : (6(5(5(3[6-9]|[4-9][0-9])|[6-9][0-9]{2})|[6-9][0-9]{3})|[7-9][0-9]{4}|[1-9][0-9]{5}|1(0[0-9]{5}|1(0[0-9]{4}|1([0-3][0-9]{3}|4(0[0-9]{2}|1(0[0-9]|1[01])))))))   These regular expression are working if used separately but I am not able to make the complete regex.  Is there any other way other than the regular expression by which I can find the invalid characters? If not, please help me in constructing the regular expression which can find invalid characters present in my XML.

The list of valid XML characters is well known, as defined by the spec it's:  #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]   My question is whether or not it's possible to make a PCRE regular expression for this (or its inverse) without actually hard-coding the codepoints, by using Unicode general categories. An inverse might be something like [\p{Cc}\p{Cs}\p{Cn}], except that improperly covers linefeeds and tabs and misses some other invalid characters.


I have a doubt in the below sentence whether to use Past Simple or Present Perfect Tense,     We have despatched the parcel yesterday.      We despatched the parcel yesterday.   I know the second one is right because the parcel was despatched yesterday which means the action is completed (Past Tense).  But what about the first sentence, because the parcel was despatched, however the parcel is not reached the customer yet. So is it ok to use "have despatched" in the sentence (Present Perfect) in the mail to inform the customer?

My friend asked me just today, "Hey, how are you?"        I said, "Tired, sleepy, and can't concentrate on my work."      He then asked, "Why so?"   Here is where the interesting part starts.       I said, "I have had a headache yesterday"   He said that I should have said "I had a headache yesterday" instead of "I have had a headache yesterday"  But all grammar books say that with Present Perfect + Past Tense we mean an action that continues into the present; has consequences in the present.  I didn't want to just tell the fact that I had a headache but I implied that that was the reason I was "Tired, sleepy, and can't concentrate on my work."  Who is right?


I finished training my Sci-Kit Learn Logistic Regression model and it is performing at 100% accuracy. However, when I went to plot the decision boundary, I got a bit confused. I am not running the typical Logistic Regression model. Instead, I have transformed the elements of the input feature matrix into nonlinear 2nd degree polynomial terms before training with the help of Sci-Kit Learn's sklearn.preprocessing.PolynomialFeatures(degree = 2) function. According to the documentation, this function transforms two features $[x,y]$ to six features $[1,x,y,x^2,xy,y^2]$. With this in mind, I wrote the general equation of the decision boundary like this: $\theta _0x^0+\theta _1x^1+\theta_2y^1+\theta_3x^2+\theta_4x^1y^1+\theta_5y^2+b=0$, while obtaining all the $\theta$ parameters from model.coef_[0][0] for $\theta_0$, model.coef_[0][1] for $\theta_1$, model.coef_[0][2] for $\theta_2$ (and so on), and the $b$ parameter from model.intercept_[0]. When I plotted this on Desmos, it came up with a weird plot nothing close to a rational decision boundary. My question: does the method model.coef_ return the parameters $\theta_0$ to $\theta_5$, IN THAT ORDER? For example, if it returns [a, b, c, d, e, f], does that mean $\theta_0$ is equal to a, $\theta_1$ is equal to b, $\theta_2$ is equal to c and so on?

I am running logistic regression on a small dataset which looks like this:    After implementing gradient descent and the cost function, I am getting a 100% accuracy in the prediction stage, However I want to be sure that everything is in order so I am trying to plot the decision boundary line which separates the two datasets.  Below I present plots showing the cost function and theta parameters. As can be seen, currently I am printing the decision boundary line incorrectly.    Extracting data  clear all; close all; clc;  alpha = 0.01; num_iters = 1000;  %% Plotting data x1 = linspace(0,3,50); mqtrue = 5; cqtrue = 30; dat1 = mqtrue*x1+5*randn(1,50);  x2 = linspace(7,10,50); dat2 = mqtrue*x2 + (cqtrue + 5*randn(1,50));  x = [x1 x2]'; % X  subplot(2,2,1); dat = [dat1 dat2]'; % Y  scatter(x1, dat1); hold on; scatter(x2, dat2, '*'); hold on; classdata = (dat>40);   Computing Cost, Gradient and plotting  %  Setup the data matrix appropriately, and add ones for the intercept term [m, n] = size(x);  % Add intercept term to x and X_test x = [ones(m, 1) x];  % Initialize fitting parameters theta = zeros(n + 1, 1); %initial_theta = [0.2; 0.2];  J_history = zeros(num_iters, 1);   plot_x = [min(x(:,2))-2,  max(x(:,2))+2]  for iter = 1:num_iters  % Compute and display initial cost and gradient     [cost, grad] = logistic_costFunction(theta, x, classdata);     theta = theta - alpha * grad;     J_history(iter) = cost;      fprintf('Iteration #%d - Cost = %d... \r\n',iter, cost);       subplot(2,2,2);     hold on; grid on;     plot(iter, J_history(iter), '.r');  title(sprintf('Plot of cost against number of iterations. Cost is %g',J_history(iter)));     xlabel('Iterations')     ylabel('MSE')     drawnow      subplot(2,2,3);     grid on;     plot3(theta(1), theta(2), J_history(iter),'o')     title(sprintf('Tita0 = %g, Tita1=%g', theta(1), theta(2)))     xlabel('Tita0')     ylabel('Tita1')     zlabel('Cost')     hold on;     drawnow      subplot(2,2,1);     grid on;         % Calculate the decision boundary line     plot_y = theta(2).*plot_x + theta(1);  % <--- Boundary line      % Plot, and adjust axes for better viewing     plot(plot_x, plot_y)     hold on;     drawnow  end  fprintf('Cost at initial theta (zeros): %f\n', cost); fprintf('Gradient at initial theta (zeros): \n'); fprintf(' %f \n', grad);   The above code is implementing gradient descent correctly (I think) but I am still unable to show the boundary line plot. Any suggestions would be appreciated.    logistic_costFunction.m  function [J, grad] = logistic_costFunction(theta, X, y)      % Initialize some useful values     m = length(y); % number of training examples      grad = zeros(size(theta));      h = sigmoid(X * theta);     J = -(1 / m) * sum( (y .* log(h)) + ((1 - y) .* log(1 - h)) );      for i = 1 : size(theta, 1)         grad(i) = (1 / m) * sum( (h - y) .* X(:, i) );     end  end   EDIT:  As per the below answer by @Esmailian, now I have something like this:  [m, n] = size(x);  x1_class = [ones(m, 1) x1' dat1']; x2_class = [ones(m, 1) x2' dat2'];  x = [x1_class ; x2_class]


I have tried and tried to open the candy box but it won't work I have all four stones whats my problem?

I've found a candy box, but I can't open it. What do I need to do? Does it have anything to do with throwing candy on the ground?


Hi i am facing a problem here while loading  dynamic content in multiple dropdown  using $(window).on("load", function(){})  in chrome it is working fine but in safari i am unable to get the dynamic content in dropdown none of them working  below is my code  $(window).on("load", countryLoad); function countryLoad() {  var urlink = " http://xxx.xxx.x.xx/Service1.svc/getCou"; $.ajax({     type: 'GET',     url: urlink,     success: function (resp) {         var select = document.getElementById("dpdclt");         var data = "";           document.getElementById("dpdclt").options.length = 0;         $("#dpdclt").append($("<option></option>").val(0).html('Select Country'));         for (var i = 0; i < resp.length; i++) {              $("#dpdclt").append($("<option></option>").val(resp[i].Sno).html(resp[i].Country));         }        },     error: function (e) {          window.plugins.toast.showLongBottom("Check your connection settings");      } });};   like the above function i have 6 other functions which i have to load on page load   $(window).on("load",function2); $(window).on("load",function3); $(window).on("load", function4); $(window).on("load", function5);   Here when the page loads in the dropdown im getting only 'Select Country' in the dropdown it is not loading dynamic contents

For all major browsers (except IE), the JavaScript onload event doesn’t fire when the page loads as a result of a back button operation — it only fires when the page is first loaded.  Can someone point me at some sample cross-browser code (Firefox, Opera, Safari, IE, …) that solves this problem? I’m familiar with Firefox’s pageshow event but unfortunately neither Opera nor Safari implement this.


I want to view other spreadsheets data with cell function in Google spreadsheet IMPORTRANGE cell function is awesome but, it required to know sheet name  so question is how can I get other sheet data with cell function without sheet name  :::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::: Data sheet has four sheet, 1st sheet name is SN1 2nd sheet name is SN2 3rd sheet name is SN3 4th sheet name is SN4 :::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::: Location in script editor 1st sheet location number is 0 2nd sheet location number is 1 3rd sheet location number is 2 4th sheet location number is 3 In Google script, I used to location number when I need to change many different specific cell data from specific sheet even I don't know sheet names :::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::: It is quite easy to get data when I know the sheet name IMPORTRANGE("URL", "sheetname!A1:D21") but, how can I get other sheet data with cell function when if I don't know sheet name.

Is there any way to display a sheet name as the result of a function in a Google Spreadsheets (exactly like , except in Google Sheets)?


I was attacked by a malware called berusose and cant open any of my files. I just need to save my pics and even if i have to erase or format the entire 1tb that will be okay by me.   Can someone help me solve this problem without paying the ransom as demanded by the hackers.

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


I have a dll file that I want to decompile. I know there are ILSpy, dotPeek and similar programs, but I have yet to find one that will actually create the cs file.  The dll I'm dealing with has several hundred classes in it and it would take days to manually copy everything.  Is there a tool that will take a dll file and return a set of cs files?

I wrote a C# application for a client a couple of years ago, but I no longer have the source code.  All I have is the EXE that I deployed on the client's PC.  Is there a way I can generate C# source code from the EXE?


I accidentally shared some photos on Google Drive with the wrong recipient (Google account). Since not all the shared documents were in the same folder, what's the easiest way to go through them and remove sharing privileges?

In Dropbox there is a place you can see all the shared items in your account (i.e., all the items you have granted others access to).  Is there a similar feature in Google Drive?  I'm not only trying to find items that are shared with other "named people", but also documents that are shared on a "anyone with link can view / edit" or "public on the internet" basis.   Franck's  seemed to work back in 2013, but Google Drive's interface has changed quite a bit since, and I'm struggling to be able to perform the same task with the new interface. I wonder if anyone knows how to do it in the new interface.


Inspired by the famous question, something subtle about it struck me.  Harry definitely witnessed and dealt with Cedric's death. It took a while before he could see the Thestrals because it takes a while to process loss. Luna can see them because of her mother's death. I believe Hagrid can see them because of one or both of his parents' deaths.  Now, is there any evidence to say if Hagrid and Luna literally witnessed death (reasonably unusual but it happens - though Luna would have seen her mother's particularly unpleasant sounding death, poor girl) or does experiencing the loss and processing the passing count? In this case, most Hogwarts age students should probably be able to see the Thestrals assuming that the death of a grandparent or other relative would count.  So, do you need to witness death, or experience a loved one's passing?

Pursuant to my question , asking why Harry couldn't see Thestrals immediately following Cedric Diggory's death, now I want to know why Harry could see Thestrals, as a re-read of canon shows that Harry actually did NOT see Cedric get killed. He had covered his face and eyes with his hands and his eyes were closed as Cedric was killed.     And then, without warning, Harry’s scar exploded with pain. It was agony such as he had never felt in all his life; his wand slipped from his fingers as he put his hands over his face; his knees buckled; he was on the ground and he could see nothing at all, his head was about to split open. From far away, above his head, he heard a high, cold voice say, ‘Kill the spare.’   A swishing noise and a second voice, which screeched the words to the night: ‘Avada Kedavra!’   A blast of green light blazed through Harry’s eyelids, and he heard something heavy fall to the ground beside him; the pain in his scar reached such a pitch that he retched, and then it diminished; terrified of what he was about to see, he opened his stinging eyes.   Goblet of Fire - Page 553 - British Hardcover   And:     ‘Righ’, now, who can tell me why some o’ yeh can see ’em an’ some can’t?’   Hermione raised her hand.   ‘Go on then,’ said Hagrid, beaming at her.   ‘The only people who can see Thestrals,’ she said, ‘are people who have seen death.’   ‘Tha’s exactly right,’ said Hagrid solemnly.   Order of the Phoenix - Page 394 - British Hardcover   According to the above passages, Harry technically did not see Cedric get killed, but witnessing a death is required for seeing Thestrals. So how is it that Harry was able to see Thestrals?


Ive searched the internet but i coudnt fix it with the answers providen. The problem is, i canot bake my model. I have the object selecten in normal and edit mode, the image is selected and created.  But it just doesnt let me bake it.

This happens pretty much every time I try to bake normal maps. It's quite a broad error message and I still don't know exactly what the problems I'm having are, only that if I keep clicking things for half an hour eventually it sometimes just works.  My understanding of the things needed:   A "Generated" blender Image that the normals are written to (In UV/Image Editor, click Image->New)   Tell blender that this is the bake output, below (this is the really confusing bit which blender seems to try to guess and fails)  A UV Map for the low poly model (you only need the geometry of the high poly and it doesn't need a UV map) Under Bake, in the rendering tab:   Bake Mode = Normals Normal Space = Tangent Selected to Active = ✓ (for the next bit)  Select the high rez object first, then the low poly object With the two objects selected, click Bake (you may have to move the mouse to see the error pops up)   Now, from what I can tell the only  (with regard to the setup and apart from the internals of baking) is how blender finds the output image:   Cycles  Have a material using an ImageTexture node which points to your normal map output. Then  says the node must be selected, but  doesn't mention selecting. Blender Render  Have a texture attached to the material that uses the image.  is pretty vague on assigning the output image. Sometimes I've found hitting tab to go to edit mode and selecting the normal map image in the UV editor to help, or at least it seemed to.   I would like to know the exact details of what blender goes looking for when you hit Bake, rather than have to guess by following tutorials. For example, it seems to look for the high and low poly objects in your selection and based off the order you select them. How does it find the normal map/image to write to for both cycles and blender render? Does the Texture need to Influence Normals or does it just need to reference the Image? etc...


So I'm building a mobile game where I have simple XP progression system that goes like this: Level1: 0-399 Total XP Level2: 400-1199 Total XP Level3: 1200-2399 Total XP So basically for the first level the player needs 400 XP to level up. Once it reaches that the exp bar goes to zero and then needs 800 XP to level up, the XP bar goes to 0 and needs 1200 and so on. I was wondering if there is a formula in order to calculate the current level of the player and the current experience (i.e. 400/800 when it has 800 total XP) from the Total XP. EDIT: So I found the formula Level = Floor(1/20 (10 + sqrt(2) sqrt(50 + TOTAL XP))) but I still can't figure out the formula to find the Current XP Thank you

In my game, XP needed to reach the next level is Current Level × Level Threshold.  Given that, how can I get my current level from the total XP ever earned?    For example:  Level Threshold = 50 Current Level = 1   Starting at level 1, I would need (1 × 50) = 50 XP to get to level 2, and so on.  Level 1: 50 XP needed to reach level 2 Level 2: 100 more XP needed to reach level 3 Level 3: 150 more XP needed to reach level 4   In other words, the progression table is as follows:  Level 1: 0 XP to 49 XP Level 2: 50 XP to 149 XP  Level 3: 150 XP to 299 XP Level 4: 300 XP to 499 XP   If I have 300 XP, I'll just reached level 4. How can I calculate that generally?


i've been searching for the perfect machine for blender.. the highest rated production level machine,that break up mentioned on blender site.  I cant go so much in to technical depth of pc components. in some parts something is lacking and something is up to the mark . its difficult to chose. So my question is very simple.  If i buy Apple MacBook Pro – MJLT2 would that be the perfect machine for blender in all aspects.Would i be able to do every ting from sculpting to rendering pretty easily on that machine? Specs for the mac book are below.  • 2.5GHz Quad-core Intel Core i7, Turbo Boost up to 3.7GHz • 16GB DDR3 RAM - 1600 • 512GB SSD Flash Storage • Intel Iris Pro Graphics + AMD Radeon R9 M370X with 2GB GDDR5 memory

What are the system requirements for working with complex geometry in Blender? Things like RAM, GPU, CPU etc.?


Here is my SignInActivityCode  public class SignInActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener, View.OnClickListener {  GoogleApiClient mGoogleApiClient; private static final int RC_SIGN_IN=0; private String TAG = "SignInActivity";  @Override protected void onCreate(@Nullable Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.signin_activity);      try{         getSupportActionBar().hide();     }catch (Exception e){         e.printStackTrace();     }      GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)             .requestEmail()             .build();      mGoogleApiClient = new GoogleApiClient.Builder(this)             .enableAutoManage(this, this)             .addApi(Auth.GOOGLE_SIGN_IN_API, gso)             .build();      SignInButton signInButton = (SignInButton) findViewById(R.id.sign_in_button);     signInButton.setSize(SignInButton.SIZE_STANDARD);     signInButton.setOnClickListener(this);  }  @Override protected void onStart() {     super.onStart();     mGoogleApiClient.connect(); }  @Override public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {  }  @Override public void onClick(View v) {     switch (v.getId()){         case R.id.sign_in_button:             signIn();             break;     } }  private void signIn(){     Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);     startActivityForResult(signInIntent, RC_SIGN_IN); }   @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {     super.onActivityResult(requestCode, resultCode, data);      // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);     if (requestCode == RC_SIGN_IN){         GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);         handleSignInIntent(result);     } }  private void handleSignInIntent(GoogleSignInResult result){     Log.d(TAG, "handleSignInResult:" + result.isSuccess());     if(result.isSuccess()){         GoogleSignInAccount acct = result.getSignInAccount();          Toast.makeText(this, "Sign in successful!", Toast.LENGTH_LONG).show();         setDefaults(acct.getDisplayName(), acct.getEmail(), acct.getIdToken());         Intent intent = new Intent(SignInActivity.this, MainActivity.class);         startActivity(intent);     }     else{         Toast.makeText(this, "Sign In Failed!\nPlease try again.", Toast.LENGTH_LONG).show();     } }  public void setDefaults(String name, String email, String token){     SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);     SharedPreferences.Editor editor = sharedPref.edit();     editor.putString("userName", name);     editor.putString("userEmail", email);     editor.putString("userIdToken", token);     editor.apply(); }   }  and here is how I am applying the information passed to the MainActivity in my nav_header_main.xml file  @Override protected void onCreate(Bundle savedInstanceState) {  initializeUserInfo(); } private void initializeUserInfo() {      userName = (TextView) findViewById(R.id.nav_user_name_tv);     userEmail = (TextView) findViewById(R.id.nav_user_email_tv);      final SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(getBaseContext());      name = sharedPref.getString("userName", "");     email = sharedPref.getString("userEmail", "");      try{         userName.setText(name);         userEmail.setText(email);     }catch(Exception e){         e.printStackTrace();     } }   and the error that I am getting in the logs     Blockquote   java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I'm trying to detect when a USB device (Android Device) is plugged into my computer. I know when I plug a device in, this file is changed /sys/kernel/debug/usb/devices and if I do a grep for the UDID of the plugged-in device it will give me the S:  SerialNumber= line.  Now, in theory, I can use inotifywait to check for modifications on the devices file and know that some device is plugged in or plugged out.  But when I do the inotifywait on it, it is not able to detect that the file is modified. And I know for sure that the file is modified, I even checked it's md5sum before and after plugging in a device, they were different. This was the command I was using inotifywait -m /sys/kernel/debug/usb/devices  Does anyone know what is going on?

This works perfectly:  $ inotifywait --event create ~/foo Setting up watches. Watches established. /home/ron/foo/ CREATE bar   However, this just sits there when directory tun0 is created under /sys/devices/virtual/net.  $ inotifywait --event create /sys/devices/virtual/net Setting up watches. Watches established.   Since those folders are world readable, I'd expect inotifywait to work.  So, what am I doing wrong?  Thanks


I have just received a kit which says that the expiration date is in April 2019 (2 months ago). I am quite confident that the extract is still okay, but I'm wondering about the yeast. Is it still alive?  It is not so easy to get new yeast, as there are no local brewing shops in my area and I'll have to order it online and wait for quite a while for it to arrive.

If I buy a tube of liquid yeast from my local homebrew store and throw it in the fridge, how long before it's no good?  How 'bout dry yeast?


When we were taught physics at school and the topic was the Inertia and , they used as an example that the moment of inertia of the bicycle wheel is the reason why we are able to keep the bicycle in the upright position.  Is this true?  If I take into account the lightweight of the rim and tire, its moment of inertia seems nothing compared to the mass of the bicycle and the biker. And I am even able to keep in the upright position a micro scooter where the wheels are really tiny.  How can I compare the significance of the rim as a flywheel with the other factors?

Why does a bike/bicycle fall when its speed is very low or close to zero and is balanced when going with a high speed?


I see this as a geo-distribution problem but i'm very confused about it. Pls help

Suppose we flip a coin until we see a head. What is the expected value of the number of flips we will take?  I am pretty new to expected value, so I tried to evaluate it by multiplying the probability of each scenario with the number of flips it took to get there (like taking the arithmetic mean). This didn't work though, because of the infinite possibilities. I'm really confused, and if someone were to provide an answer, I would really appreciate it if they could go into detail.


As i have low internal memory only 128 GB. so i do not wish to install in my hard drive. Instead i wish to use it on my flash drive itself with persistence. My problem is i cant get the wifi to work.

On this site I see hundreds if not a thousand questions being asked about issues with a Wireless LAN adapter not being detected/recognized by Ubuntu. Some mainstream adapters appear to be utterly broken in Linux support, while others just require some simple steps to get it to work.  The options to get it to work appear to be infinitely huge and I have no clue where to get started!  What is considered 'best practice'? What order of things to try is most efficient in terms of time, effort and imposes minimal risk to my Ubuntu installation? Please help me save time and guide me what to do, step by step.


For a prime number $p \neq 11$, do we have $p = x^2 + xy + 3y^2$ for some $x$, $y \in \mathbb{Z}$ if and only if $p \equiv 1, 3, 4, 5, 9$ mod $11$?  An example where this is true:$$5 = 1^2 + 1 \times 1 + 3 \times 1^2.$$I know that $\mathbb{Z}[(1 + \sqrt{-11})/2]$ is a PID.

For a prime number $p \neq 3$, do we have that$$p = x^2 + xy + y^2$$for some $x$, $y \in \mathbb{Z}$ if and only if$$p \equiv 1 \text{ mod }3?$$I suspect this is true from looking at the example$$7 = 2^2  + 2 \times 1 + 1^2.$$Here is a thought I have so far that might be helpful towards solving this: I know that $$\mathbb{Z}[(1 + \sqrt{-3})/2]$$is a PID. But I am not sure what do from here. Could anybody help?


Some of our wired ethernet data connections are energized with  at 48 volts.  But not all of our devices utilize POE.  Is it harmful to plug a device into POE when the device's NIC does not utilize POE?  I would like to use the wired ethernet connection for data on a device which does not utilize POE.

I have a switch with Power over Ethernet capabilities. Is it allowed to connect a PC to a PoE switch?


I have a table in the database contains ID which is the primary key and auto incremented, and RFC the RFC should be auto incremented as well like RFC-0001 then RFC-0002 but on the HTML/PHP part for some reason I'm doing something wrong and I dont know how to fix it any ideas ? this is my database table  and this is my php html code <?php $servername = "localhost"; $username = "root"; $password = ""; $dbname = "change";  // Create connection $conn = new mysqli($servername, $username, $password, $dbname); // Check connection if ($conn->connect_error) {   die("Connection failed: " . $conn->connect_error); }  ?> <?php $try="select * from test order by id desc limit1"; $result= mysqli_query($conn,$try); $row=mysqli_fetch_array($result); $lastid= $row['rfc']; if ($lastid == " ") {  $empid ="RFC-0001"; } else {  $empid = substr($lastid, 4);  $empid= intval($empid);  $empid= "RFC-".($empid +1); } ?> <html> <body> <form method="post" action=""> <input type="text" name="ID" value="<?php echo $empid; ?>"readonly> </br> <input type="text" name="name"> </br> <input type="button" name="done" value="done"> </form>  </body> </html>

I need to cast single figures (1 to 9) to (01 to 09). I can think of a way but its big and ugly and cumbersome. I'm sure there must be some concise way. Any Suggestions


There are infinite number of real numbers between 0 and 1,i.e in the interval [0,1]. So definitely there should be more numbers in the interval [0,10] because it includes the numbers in the first case and also the numbers in the interval (1,10]. But we can map(one to one) every number in [0,1] to every number in [0,10]. This means that there are equal numbers in [0,1] and [0,10]. What does this really mean though??

There are infinitely many real numbers between any two real numbers, therefore there are infinitely many real numbers in the range $[0,1]$ as there are in $[1, \infty)$. In a mathematical sense, are there more numbers in one range as opposed to the other?  What about $[0,1]$ and $[0, \infty)$ ?  I'd assume this is akin to how limits work in that the limit as $x\to\infty$ of $\frac{x^x}{\log(x)}$ is $\infty$, even though both the numerator and denominator approach infinity.


I've learnt ibp, substitution.. but it seemed that i cannot just use those to solve the problem..  Please help me..   $$\int\limits_{-1}^{1} \sin(x^3) \mathrm{d}x$$

$$\int \sin (x^3)dx$$ I have tried some substitutions, but I haven't reached the goal... Can you help me?


I try to install cuda 7.5 on Ubuntu 14.04. To verify that your GPU is CUDA-capable, I write   $ lspci | grep -i nvidia    command. I don't see anything. Then i write   update-pciids   I take   update-pci ids /usr/share/misc/pci.ids.new is read-only   message. I login as a root but i can not do. Are there anyone who solved this problem? I also new in ubuntu.

I'm going through CUDA's documentation and following this page () to see whether or not my machine and distro can support it. To verify if i have a CUDA capable GPU, i had to enter this command      lspci | grep -i nvidia   upon entering this command i got no result, and i followed it up by entering this      update-pciids   ^^i got the following result upon entering the aforementioned command      update-pciids: /usr/share/misc/pci.ids.new is read-only   any ideas on how to verify the compatibility of my card with CUDA?


I am looking for an iterator which takes as an input multiple ranges in python (or for example lists) and returns all possible combinations for these. Preferably in an iterator so it does not store all combinations in memory. I know how to code it myself, but it seems to me a quite common function so i cannot imagine that it doesn't exists already in some library. This is basically the idea:  a = range(0,2) b = range(2,4)  for i,j in someFunc(a,b):     print(i,j)   This would then print:  0 2 0 3 1 2 1 3   This can ofcourse be achieved by multiple loops:   for i in a:     for j in b:         print(i,j)   But i am looking for one function which can accept unlimited ranges as arguments. It seems as such a common function, but i have not been able to find it anywhere.

How can I get the Cartesian product (every possible combination of values) from a group of lists?  Input:   somelists = [    [1, 2, 3],    ['a', 'b'],    [4, 5] ]   Desired output:  [(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), (2, 'a', 5) ...]


I am using apple configurator 1.7.2. Accidentally someone upgrade IOS to version 11 as image for every no ipod touch. Is any way I can go back to version 10? I need it for run older application which not support version 11 yet. Thanks for any help

I'm trying to downgrade my iPhone from the current iOS to an older one, as per .  But every time I try, I always receive this error:     The iPhone could not be restored. This device isn't eligible for the requested build.     I have tried many times with and without DFU mode. Any ideas regarding this?


I know how to prove the theorem of the following:  A function f is continuous if and only if the preimage of any open set in Y is open in X.  I am wondering how to show that the theorem is equivalent to the two different definitions of continuity of i) open balls and ii) delta epsilon.

A function $f: M\rightarrow N$ is defined to be continuous iff $\forall$ open set $U\subseteq N$, the preimage of $U$ is also open.  I was trying to prove that such a definition would be equivalent to the $\epsilon -\delta$ definition in a metric space, and I could only do so if I assume $f$ is surjective, or otherwise a counterexample would be $g: \mathbb{R}\rightarrow\mathbb{R}$ where $g(x)=x^2$. As if I take $U=(-1,1)$, then its preimage is $[0,1)$, which is neither open or closed. In fact, any $U$ containing elements that cannot be achieved by $g$ would face the same problem.  So I was wondering that have I remembered the definition of preimage wrong, or do I need to make sure that $U$ must be chosen from the image set of $f$?


my system specifications are: Compaq Presario model CPU: Intel Celeron(R) CPU 2.93GHz Speed and Memory: 2.95GHz, 632 MB of RAM hard disc: 40 GB

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


I need to update the records of a table which has a wrong date (1970-01-01), using the next record's data (according to the incremental gkey field).   So, if I do this query:  SELECT aa.gkey,        aa.course_date,        (select course_date from BI.fact_training_event_tbl bb where bb.gkey = (             select min(cc.gkey)              from BI.fact_training_event_tbl cc                   where cc.gkey > aa.gkey)) as next_date from BI.fact_training_event_tbl aa where course_date = '1970-01-01'   It brings the records correctly, as expected:  gkey   course_date  next_date ====   ===========  ========= 4103   1970-01-01   2017-03-23 4884   1970-01-01   2017-03-22 5047   1970-01-01   2017-03-23   I now need to update the course_date field with next_date, but if I try running the following, I get the      Error Code 1093. You can't specify target table 'aa' for update in FROM clause:   update BI.fact_training_event_tbl aa     set course_date =     (select course_date from BI.fact_training_event_tbl bb where bb.gkey = (             select min(cc.gkey)     from BI.fact_training_event_tbl cc          where cc.gkey > aa.gkey)) where course_date = '1970-01-01'   Any ideas on how I can pull this off?  I want to make clear that this question is not answered earlier since the thread about error 1093 shows a simple subquery. In my case, I'm doing a lookup for the next record referencing the main table. Please don't tag it as a duplicate.

I have a table story_category in my database with corrupt entries. The next query returns the corrupt entries:  SELECT *  FROM  story_category  WHERE category_id NOT IN (     SELECT DISTINCT category.id      FROM category INNER JOIN         story_category ON category_id=category.id);   I tried to delete them executing:  DELETE FROM story_category  WHERE category_id NOT IN (     SELECT DISTINCT category.id      FROM category        INNER JOIN story_category ON category_id=category.id);   But I get the next error:      #1093 - You can't specify target table 'story_category' for update in FROM clause    How can I overcome this?


My idea was to use the homomorphism theorem for [$S_n$,$S_n$] as for any f:$S_n$ → C* by setting N=[$S_n$,$S_n$] we know that there is exacly one g:$S_n$/[$S_n$,$S_n$] → C*  However we know that $S_n$/[$S_n$,$S_n$]=$S_n$/$A_n$, but $S_n$/$A_n$ ≅ Z/2Z  Therefore there is exacly one g:Z/2Z → C* so all elements of a ∈ C* give us ord(a)|g[Z/2Z] so a can only be -1 or 1.   Now we know that f:$S_n$ → {-1,1}  Aaaaand I'm stuck. :/

I need to find all group homomorphisms of $S_n\to\mathbb{C}^*$ (for $n\ge2$), and also all group homomorphisms of $A_n\to\mathbb{C}^*$ (for $n\ge2$).  Someone on this site, two years ago, seems to have already asked the same question (). I understand what the questioner says there, but I don't understand it when he says:     Therefore there is exactly one $g:\mathbb{Z}/2\mathbb{Z}\to\mathbb{C}^*$, so all elements of $a\in\mathbb{C}^*$ give us $\operatorname{ord}(a)\mid g[\mathbb{Z}/2\mathbb{Z}]$, so $a$ can only be $-1$ or $1$. Now we know that $f:S_n\to\{-1,1\}$ …   What is he saying there? And how to go on from there? (I do not understand the answer given either …)  I hope that someone here can help me further. (And if I'm not allowed to ask this question because is has already been asked two years ago, please tell me what to do instead).  Thank you in advance!


Is it possible to have $m$ rows with $n$ variables over F2, where $m < n$ that will have some combination of rows that can form a zero vector, but there will be no zero vectors in reduced-row echelon form? Please provide an example of such a setup if this is indeed possible.

Given $m$ rows with $n$ variables where $m < n$, and given that there exists a combination of some of the rows that gives a zero vector. Is it promised when computing the reduced-row echelon form, with Gaussian elimination to find a zero vector?  Update: I clearly don't know, how to pick up the right words to ask my question. So let me give you the full context and please help me say it right, so the question will make sense. I am solving step 3 in the quadratic sieve algorithm, here is a  description of it.  Suppose the composite number N is being factored. Bound $B$ is chosen, and the factor base is identified (which is called $P$), the set of all primes less than or equal to $B$. Next, positive integers $z$ are sought such that $z_2$ mod $N$ is B-smooth. Therefore it can be written, for suitable exponents $a_i$, $${\displaystyle z^{2}{\text{ mod }}N=\prod _{p_{i}\in > P}p_{i}^{a_{i}}}$$ When enough of these relations have been generated (it is generally sufficient that the number of relations be a few more than the size of P), the methods of linear algebra can be used (for example, Gaussian elimination) to multiply together these various relations in such a way that the exponents of the primes on the right-hand side are all even: $${\displaystyle {z_{1}^{2}z_{2}^{2}\cdots z_{k}^{2}\equiv \prod > _{p_{i}\in P}p_{i}^{a_{i,1}+a_{i,2}+\cdots +a_{i,k}}\ {\pmod {N}}\quad ({\text{where }}a_{i,1}+a_{i,2}+\cdots +a_{i,k}\equiv 0{\pmod > {2}})}}$$  Now, let's say I found $m$ relations and the number of primes in $P$ is $n$, such that $m<n$. It is given that there exists a combination of some of the $m$ relations that their product is a square number. My question is: When I perform the Gaussian elimination over F2 to find a null space combination, is it promised that I will find one? I successfully implemented the algorithm and the matrix part of my implementation works. But what I see is that if I found a null space(a combination of making a null space) and latter I add more relations(still $m < n$), I lose the null space solution and not able to solve the matrix again. Each time I add a new relation I start solving it from the beginning, I don't remember any previous state. So what I want to know, could it be that there is a limitation with the Gaussian elimination algorithm, that it does not promise to find the null space if $m < n$?


Not a big deal but I thought I'd report it:  While I vist movies and TV, all my badges from other sites look like reels. I suppose whenever a site used a custom badge icon, it'll end up looking like that.

It's so cool that the notification reminds you of the colour of badge you've earned. But I am a little puzzled by the symbols:      Is it feasible to use the symbol from the earned site? At the moment it uses the symbol from the site I happen to be on (as you can see by looking to the left of the dropdown in each case.)


I am a beginner and I write article in slovak language. There is a rule to not leave single-letter words or preposition at the end of line (for example a, i, na, pre etc.) but to move them to the next one.   I know that I can use "~", but in this article there are a lot of single letters and prepositions, so I cannot use it every time. Can somebody help me, please? :(   Thank´s.

This question led to a new feature in a package:      I come from Poland and I'm writing some text in my native language. One of our typography standards is that we do not leave one-letter words at the end of a line. For example:  Mietek poszedl do sklepu i kupil jabola   is illegal, and correctly it should be as follows:    Mietek poszedl do sklepu  i kupil jabola   I don't know if there is such a rule in US/English typography also, but I cannot find any latex setting that would fix such errors. The only solution I've found so far is to add the "~" character, which seems to work as whitespace, but also prevents to break connected words between lines. So I have to write:  Mietek poszedl do sklepu i~kupil jabola   Is there any other way to do so? I've tried with   \widowpenalty10000   \clubpenalty10000    which prevents orphans, but it seems that 'orphans' for us (Polish) is something different than for Americans ;) In the US orphan is the first line of a paragraph on the last line of a page (at least I think so), but for us, 'orphan' is such a single-letter word at the end of a line.


If I inline a function.  The function call body will be copied instead of issuing a call() to it. Why can that lead to bad performance?   Edit: And what about cache misses because of to big functions then? Why does the rule of thumb "only inline functions with max 3 lines" exist then?

While it would be very convenient to use inline functions at some situations,  Are there any drawbacks with inline functions?  Conclusion:  Apparently, There is nothing wrong with using inline functions.  But it is worth noting the following points!   Overuse of inlining can actually make programs slower. Depending on a function's size, inlining it can cause the code size to increase or decrease. Inlining a very small accessor function will usually decrease code size while inlining a very large function can dramatically increase code size. On modern processors smaller code usually runs faster due to better use of the instruction cache.  The speed benefits of inline functions tend to diminish as the function grows in size. At some point the overhead of the function call becomes small compared to the execution of the function body, and the benefit is lost  There are few situations where an inline function may not work:   For a function returning values; if a return statement exists. For a function not returning any values; if a loop, switch or goto statement exists.  If a function is recursive.   The __inline keyword causes a function to be inlined only if you specify the optimize option. If optimize is specified, whether or not __inline is honored depends on the setting of the inline optimizer option. By default, the inline option is in effect whenever the optimizer is run. If you specify optimize , you must also specify the noinline option if you want the __inline keyword to be ignored.


Why didn't Dumbledore enchant a portrait of himself to aid the trio in their hunt for Horcruxes?  Surely, if he foresaw Ron leaving and coming back, reason for why he left him the Deluminator via his last will and testament, and that Harry and Hermione would have to compensate for the decreased magical capacity/capability provided by Ron while he was absent, then he would have thought of a way to help them (via a portrait). He could have also taught the Fidelius Charm to them, seeing as how that prevented the Death Eaters from entering 12 Grimmauld Place even though they were aided by the Taboo Jinx/Curse, but Hermione's protective enchantments (Protego Totalum, Salvio Hexia, Repello Muggletum, Muffliato, Cave Inimicum, Disillusionment Charm, etc...) collapsed entirely against the Taboo Jinx/Curse. There might be other times during the Horcrux hunt where he would have been helpful, but these are the only ones I could think of right now.   The quote proving that Dumbledore knew that Ron would leave and comeback is here, in page 391, British Edition, of Harry Potter and the Deathly Hallows:     And still his scar prickled, and he knew that Voldemort was getting there too. Harry understood, and yet did not understand. His instinct was telling him one thing, his brain quite another. The Dumbledore in Harry’s head smiled, surveying Harry over the tips of his fingers, pressed together as if in prayer.   You gave Ron the Deluminator. You understood him ... you gave him a way back ...   And you understood Wormtail too ... you knew there was a bit of regret there, somewhere ...   And if you knew them ... what did you know about me, Dumbledore?   Am I meant to know, but not to seek? Did you know how hard I’d find that? Is that why you made it this difficult? So I’d have time to work that out?

Dumbledore's portrait was in the headmaster’s office, Harry could have interacted with it. McGonagall would have allowed him private conversations with it if necessary. Even if it was just an imprint, it would have been a powerful guide to Harry, answering any questions he might have had... but we don't see this, and instead Harry just struggles with himself over whether the Hallows really exist and if they're worth pursuing over the Horcruxes... do you think JKR forgot about this possibility?


I've defined a named range called Ticker that references 'Sheet 1!A1'. I'd like to know when this cell changes value, so that I can run trigger some functions to run. I know that onEdit seems to be the way to do this: function onEdit(e) {   var range = e.range;    if(range == NamedRange('Ticker')) {     // do something...   } }  I'd like to know the correct syntax for making the named range comparison:   if(range == NamedRange('Ticker')) {     // do something...   }

I'd like to pull values from a named range into a calculation. I have this function:   function getNamedRange(n){   SpreadsheetApp.getActiveSpreadsheet().getRangeByName(n); }   Seems pretty simple. I have a named range called "budgetItems". It definitely exists and has about 6 values in it. But when I try to pull the values with    var items = getNamedRange("budgetItems"); items.getValues();   it usually says items is null. I've gotten it to work in the past but it seems really flaky. I suspect there is eventual consistency and caching goofing things up here.   I've attached this function (to pull the values from the range) to a menu item. When I run that menu item it takes about 15s to run 5 lines of js -- and then fails. That's... suspicious.


I asked a question  but it seems Tikz is a better option. I was trying to draw the following logo of an atom using Mathematica, but I could only figure out how to draw intersecting ellipses, not a nice logo like below. Do you know how to draw it by Tikz?

I would like to draw this picture by tikz:  This is what I could achieve for now: \documentclass{standalone} \usepackage{tikz} \pagecolor{yellow}  \begin{document}  \color{orange!80!red}  \begin{tikzpicture}     \clip (-0.5,-0.5) rectangle (.5,.5);          \begin{scope}[xshift=4,yshift=12.4]         \fill (0,0) circle (0.05);     \end{scope}          \begin{scope}[xshift=10.5,yshift=-8.5]         \fill (0,0) circle (0.05);     \end{scope}          \begin{scope}[xshift=-11.5,yshift=-5.5]         \fill (0,0) circle (0.05);     \end{scope}          \clip[xshift=4,yshift=12.4] (0,0) circle (0.06) [insert path ={(-2,-2) rectangle (2,2)}];     \clip[xshift=10.5,yshift=-8.5] (0,0) circle (0.06) [insert path ={(-2,-2) rectangle (2,2)}];     \clip[xshift=-11.5,yshift=-5.5] (0,0) circle (0.06) [insert path ={(-2,-2) rectangle (2,2)}];          \begin{scope}[rotate=-70]         \clip (-0.015,0.005) ellipse (0.17 and 0.46) [insert path ={(-0.5,-0.5) rectangle (.5,.5)}];         \fill (0,0) ellipse (0.2 and 0.5);     \end{scope}          \begin{scope}[rotate=50]         \clip (-0.015,0.005) ellipse (0.17 and 0.46) [insert path ={(-2,-2) rectangle (2,2)}];         \fill (0,0) ellipse (0.2 and 0.5);     \end{scope}          \begin{scope}[rotate=-10]         \clip (-0.015,0.005) ellipse (0.17 and 0.46) [insert path ={(-2,-2) rectangle (2,2)}];         \fill (0,0) ellipse (0.2 and 0.5);     \end{scope}          \begin{scope}[xshift=-0.33,yshift=0.05]         \fill (0,0) circle (0.08);     \end{scope}  \end{tikzpicture}  \end{document}  I don't know how to draw the crossing of each ellipse. Note that the background color is not determined and may NOT be white, so one can't just draw a wider ellipse of background color behind each ellipse. I believe this can be achieved by multiple use of \clip, just like the three circle I've drown here, but for the ellipses it seems more tricky and I have no idea with it. Do you have any suggestions?


Those are from   Here is an interface :  public interface ISupportSampling {     double? SamplingPercentage { get; set; } }   And here is what I can see from VS a class that is supposed to implement the interface.  #region Assembly Microsoft.ApplicationInsights, Version=2.6.4.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35 // nsame namespace as the above interface public sealed class EventTelemetry : ITelemetry, ISupportProperties, ISupportSampling, ISupportMetrics {     public EventTelemetry();     public EventTelemetry(string name);      public DateTimeOffset Timestamp { get; set; }     public string Sequence { get; set; }     public TelemetryContext Context { get; }     public string Name { get; set; }     public IDictionary<string, double> Metrics { get; }     public IDictionary<string, string> Properties { get; }      public ITelemetry DeepClone(); }   You can see that the only property from the interface is not in the list of public properties.    So, it means that, when coding, 2 things happen that are not desirable :  1)   This code  EventTelemetry eventTelemetry; // ... eventTelemetry.SamplingPercentage = 100;   Causes the following compilation error :     'EventTelemetry' does not contain a definition for   'SamplingPercentage' and no accessible extension method   'SamplingPercentage' accepting a first argument of type   'EventTelemetry' could be found (are you missing a using directive or   an assembly reference?`   2)   Also, the SamplingPercentage property will not show up in autocomplete.    Why ? Am I being lied to by VS on what I see from the class ? (that SamplingPercentage is indeed present and public, but for some reasons not shown to me ?)  My current workaround (and also given in the last snippet in  ) is to cast as this :  ((ISupportSampling) eventTelemetry).SamplingPercentage = 100;   Is there a more "developper friendly" way, without using explicit cast ? (using Visual Studio 2017)

What are the differences in implementing interfaces implicitly and explicitly in C#?  When should you use implicit and when should you use explicit?  Are there any pros and/or cons to one or the other?    Microsoft's official guidelines (from first edition ) states that using explicit implementations are not recommended, since it gives the code unexpected behaviour.  I think this guideline is very valid in a pre-IoC-time, when you don't pass things around as interfaces.  Could anyone touch on that aspect as well?


So this is a pretty general question, and I'm not even sure what it is I should be asking. Basically my abstract algebra textbook does not clearly define conjugations and just sort of throws out this: $$g⋅a = gag^{-1}$$ I don't know what this comes from or what it is saying, but from my trying to figure this out, it seems like it comes up a lot, and I just can't make sense of it. I keep trying to visualize everything group-related as symmetric permutations, but I imagine this is very limited, especially when considering a group acting on itself. (How does that work?) Are there other ways of visualizing what this is trying to say? Let me know if providing the hw question that led to this confusion is worth commenting

I am learning group theory, and while learning automorphisms, I came across conjugation as an example in many textbooks. Though the definition itself, (and when considering the case of abelian groups), it seems pretty innocent, I have to admit that I have no intuition about whats happening, or why even such a map is important. Did anyone feel this way when you learnt it? Any examples/references that you have found useful when you learnt it?