How is the square root function implemented?

+2 A:

There are lots of ways to compute the square root. Wikipedia has the details for a pseudo computer algo too. Are you looking for the implementation in a specific library or for a specific precision?

Gangadhar 2010-08-27 05:33:14

A:

If you're interested, the Numerical Recipes book has lots on how to calculate square roots, sines and cosines, exponentials, logarithms, and so on.

Philip Potter 2010-08-27 07:58:14

A:

Take a look here. It contains 13 C++ implementations of sqrt, together with speed and precision comparison.

Lior Kogan 2010-08-27 08:11:37

The author of the article tries to measure the speed of the functions by averaging the time, which is good. It's just that it's implemented wrong.

Peter Stuifzand 2010-08-27 09:22:35

A:

Square root is usually based on Newton's iterative method:

http://mathworld.wolfram.com/NewtonsIteration.html

duffymo 2010-08-27 09:38:11

A:

On Intel hardware, it's often implemented on top of the hardware SQRT instruction. Some libraries just use the result of that straight off, some may put it through a couple of rounds of Newton optimisation to make it more accurate in the corner cases.

Tom Anderson 2010-08-27 09:42:09

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How is the square root function implemented?

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