On Mar 2, 5:26 pm, Ben123 <ben.is.loca...@gmail.com> wrote: > On Mar 2, 9:04 am, Arthur Mc Coy <1984docmc...@gmail.com> wrote: > > > What do you mean by "arbitrary precision" ? Each method of calculating > > of something has its own precision... > > If you are unfamiliar with arbitrary precision, I'm referring > tohttp://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic > > Suppose I find the eigenvalues of a matrix and the eigenvalues range > from 1 to 0.0001. This can be handled by numpy in Python because the > smallest eigenvalue is larger than then numerical precision of 1E-19. > However, if the range of eigenvalues is 1 to 1E-40, then I will need > to increase the precision of all calculations leading up to finding > the eigenvalues. > > I am working with complex valued matrices and I expect to get real > eigenvalues back (based on the physics of the system). The precision > of numpy is apparent from the imaginary component of the eigenvalues I > find, currently 1E-19 or 1E-20. I need better precision for small > eigenvalues. > > In case you are curious, the complex-valued matrices are 20x20. > > Thanks
You probably have to change the method of finding eigenvalues. Which one do you use? Power or algebraic ? Do you use Gaussian method to simplify matrices ? Languages can't support infinitely large or small numbers, so try to multiply the inner variables by 10^n to increase their values if this will not involve on the method. For example, I did this when was calculating geometric means of computer benchmarks. In such way you will be storing the number of zeros as n. Yes, interesting what are you calculating. -- http://mail.python.org/mailman/listinfo/python-list
