In article <mailman.9917.1399914607.18130.python-l...@python.org>, Joseph Martinot-Lagarde <joseph.martinot-laga...@m4x.org> wrote: >Le 10/05/2014 17:24, Albert van der Horst a écrit : >> I have the following code for calculating the determinant of >> a matrix. It works inasfar that it gives the same result as an >> octave program on a same matrix. >> >> / ---------------------------------------------------------------- >> >> def determinant( mat ): .. >> result = lastr[jx] >> assert(result<>0.) ... >> assert(result<>0.) >> nom *= result # Compenstate for multiplying a row. ... >> assert(nom<>0.) .. >> >> /----------------------------------------- >> >> Now on some matrices the assert triggers, meaning that nom is zero. >> How can that ever happen? mon start out as 1. and gets multiplied >> with a number that is asserted to be not zero. >> >> Any hints appreciated. >> >> Groetjes Albert >> >I know it's not the question, but if you want a replacement for octave >did you try numpy (and scipy) ? The determinant would be computer faster >and with less memory than with your function.
I'm using several programming languages in a mix to solve Euler problems. This is about learning how octave compares to python for a certain kind of problem as anything. The determinant program I had lying around, but it was infinite precision with integer only arithmetic. Then I made a simple modification and got mad because I didn't understand why it didn't work. I have used numpy and its det before, but I find it difficult to remember how to create a matrix in numpy. This is the kind of thing that is hard to find in the docs. Now I looked it up in my old programs: you start a matrix with the zeroes() function. I expect the built in determinant of octave to be on a par with corresponding python libraries. > >--- Groetjes Albert -- Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
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