Convert a matrix to a list of equations

linear-algebra

asked 2018-08-29 21:24:30 +0100

matrixman
11 ●1 ●1 ●2

Hi there, I have a matrix A with entries depending linearly on a number of parameters a1,...,an, and would like to solve the equation A=0. It seems I need to convert A to a list of equations of the form "entry=0" and then use solve(eqns, a1,...,an); but how do I convert A to such a list?

Any help appreciated!

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answered 2018-08-29 22:41:04 +0100

tmonteil
27413 ●31 ●204 ●517 http://wiki.sagemath.o...

Given a matrix M, say:

sage: M = matrix(ZZ, [[4, 27, -3], [-3, 2, -1], [-177, 45, 5]])
sage: M
[   4   27   -3]
[  -3    2   -1]
[-177   45    5]

You can get its entries by doing:

sage: M.coefficients()
[4, 27, -3, -3, 2, -1, -177, 45, 5]

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Thanks tmonteil, that's good to know! Is there also a way to convert the list of coefficients to a list of equations, setting each coefficient == 0?

matrixman ( 2018-08-29 23:33:47 +0100 )edit

yes, like this:

[c == 0 for c in M.coefficients()]

eric_g ( 2018-08-30 13:29:33 +0100 )edit

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Asked: 2018-08-29 21:24:30 +0100

Seen: 1,185 times

Last updated: Aug 29 '18

Convert a matrix to a list of equations edit