Re: linear algebric equations
Am 07.12.20 um 17:59 schrieb Tito Sanò: Regarding the solution of linear algebraic equations I noticed a big difference in the computation time in Python compared to the old fortran language. I have compared both the linelg and lapack.dgesv-lapack.zgesv modules with the fortan: dgelg and f04adf. The difference in computation time is enormous: for example for 430 degrees of freedom it is about 24 min in Python versus about 1 sec in fortran. There must be something seriously wrong. If I understand correctly, you want to solve an 430x430 matrix with LU decompositino (that is what dgesv from LAPACK does). The following code takes less than a second on my machine: ==430.py== import numpy as np # create a 430x430 random matrix A = np.random.randn(430,430) # right hand side b = np.ones(430) # solve it x = np.linalg.solve(A, b) print(x) time python3 430.py real0m0.318s user0m0.292s sys 0m0.046s If it takes longer than 1s, there is something wrong with your system. Christian -- https://mail.python.org/mailman/listinfo/python-list
Re: linear algebric equations
On Mon, 7 Dec 2020 at 20:38, Tito Sanò wrote: > Is it possible to get better performance in Python? Have you installed BLAS for Scipy? What OS do you have? -- https://mail.python.org/mailman/listinfo/python-list
RE: linear algebric equations
Yes. Import os, and use os.system( ) to call your Fortran (or C) executable. If the executable saves results in a file or files, Python can read them in an format a nice overall report. In html or xml, if you like. Using Python as glue, the execution time will be exactly what it was for your executable, because Python will call it; and in a second of so after it finishes Python can read in results and format whatever report you like. --- Joseph S. -Original Message- From: Tito Sanò Sent: Monday, December 7, 2020 11:59 AM To: python-list@python.org Subject: linear algebric equations Regarding the solution of linear algebraic equations I noticed a big difference in the computation time in Python compared to the old fortran language. I have compared both the linelg and lapack.dgesv-lapack.zgesv modules with the fortan: dgelg and f04adf. The difference in computation time is enormous: for example for 430 degrees of freedom it is about 24 min in Python versus about 1 sec in fortran. Is it possible to get better performance in Python? Thanks in advance Tito Sano' Roma Italy Cell: 339 6903895 -- https://mail.python.org/mailman/listinfo/python-list
Re: linear algebric equations
On Mon, Dec 7, 2020 at 11:36 AM Tito Sanò wrote: > Regarding the solution of linear algebraic equations I noticed a big > difference in the computation > > time in Python compared to the old fortran language. > > I have compared both the linelg and lapack.dgesv-lapack.zgesv modules with > the fortan: dgelg and f04adf. > > The difference in computation time is enormous: > > for example for 430 degrees of freedom it is about 24 min in Python versus > about 1 sec in fortran. > > Is it possible to get better performance in Python? > Can you make your test code available for examination? If you are using CPython, are you also using numpy? Or numba? If you are using pure Python, have you tried Pypy3? HTH. -- https://mail.python.org/mailman/listinfo/python-list
linear algebric equations
Regarding the solution of linear algebraic equations I noticed a big difference in the computation time in Python compared to the old fortran language. I have compared both the linelg and lapack.dgesv-lapack.zgesv modules with the fortan: dgelg and f04adf. The difference in computation time is enormous: for example for 430 degrees of freedom it is about 24 min in Python versus about 1 sec in fortran. Is it possible to get better performance in Python? Thanks in advance Tito Sano Roma Italy Cell: 339 6903895 -- https://mail.python.org/mailman/listinfo/python-list
