I want to find the square root of a number without using the math module,as i need to call the function some 20k times and dont want to slow down the execution by linking to the math module each time the function is called 
Is there any faster and easier way for finding square root?
In some special cases you can trade program size for blistering speed. Create a large array and store the pre-calculated result for every square root operation (using the input value as the index). It's pretty limited but you won't get anything faster.
(That's how quake did it)
How to perform square root without using math module?