title: ValueError: Error when checking target: expected lstm_2 to have 3 dimensions, but got array with shape (1, 184800)
body: <p>My data consists of 26 columns and 231000 rows. I have tried to fix the error for a few days now but I am still unsure on what needs to be done. Please do give your insight on this problem. Below is my full code </p>
  
  <pre><code>import pandas as pd
  import numpy as np
  from sklearn.model_selection import train_test_split
  from sklearn import datasets, linear_model
  from matplotlib import pyplot as plt
  from keras.models import Sequential
  from keras.layers import Dense
  from keras.layers import LSTM
  from keras.layers import RepeatVector
  from keras.layers import TimeDistributed
  
  # load dataset
  dataframe = pd.read_csv("AHPS_26C_Norm.csv", header=None)
  dataset = dataframe.values
  X = dataset[1:, 1:26].astype(float)
  Y = dataset[1:, 0]
  
  X = np.array(X)
  Y = np.array(Y)
  X_train, X_test, Y_train, Y_test = train_test_split(X, Y, test_size=0.20, random_state=42)
  
  n_steps = len(X_train)
  n_features = 25
  batch_size = 1
  X_train = X_train.reshape(1, n_steps, n_features)
  Y_train = Y_train.reshape(1, n_steps)
  
  # create model
  model = Sequential()
  model.add(LSTM(100, activation='relu', batch_input_shape=(1, n_steps, n_features)))
  model.add(RepeatVector(n_steps))
  model.add(LSTM(100, activation='softmax', return_sequences=True))
  model.compile(optimizer='adam', loss='sparse_categorical_crossentropy', metrics=['accuracy'])
  
  # fit model
  model.fit(X_train, Y_train, epochs=300, validation_data = (X_test, Y_test), batch_size= batch_size, verbose=0)
  print(model.summary())
  
  
  # Final evaluation of the model
  scores = model.evaluate(X_train, Y_train, verbose=0)
  print("Accuracy: %.2f%%" % (scores[1] * 100))
  </code></pre>
  
  <p>Below is the error I received:</p>
  
  <pre><code>Traceback (most recent call last):
    File "C:/Users/Iliya Juhari/.PyCharmCE2018.3/config/scratches/scratch_3.py", line 40, in &lt;module&gt;
      model.fit(X_train, Y_train, epochs=300, validation_data = (X_test, Y_test), batch_size= batch_size, verbose=0)
    File "C:\Users\Iliya Juhari\PycharmProjects\untitled\venv\lib\site-packages\keras\engine\training.py", line 1154, in fit
      batch_size=batch_size)
    File "C:\Users\Iliya Juhari\PycharmProjects\untitled\venv\lib\site-packages\keras\engine\training.py", line 621, in _standardize_user_data
      exception_prefix='target')
    File "C:\Users\Iliya Juhari\PycharmProjects\untitled\venv\lib\site-packages\keras\engine\training_utils.py", line 135, in standardize_input_data
      'with shape ' + str(data_shape))
  ValueError: Error when checking target: expected lstm_2 to have 3 dimensions, but got array with shape (1, 184800)
  </code></pre>