[SciPy-user] null space of a matrix
Robert Kern
rkern at ucsd.edu
Wed Jun 29 16:08:44 EDT 2005
Ryan Krauss wrote:
> This is a completely trivial addition to Richard's submission, but here
> is the function I am using to implement the null function if anyone
> wants to copy and paste it into there own code:
>
> def null(A, eps=1e-15):
> u, s, vh = scipy.linalg.svd(A)
> null_mask = (s <= eps)
> null_space = scipy.compress(null_mask, vh, axis=0)
> return scipy.transpose(null_space)
>
> (this assumes you have already got an import scipy somewhere in the file)
> (It made more sense to me to return column vectors.)
Point. You may also need to conjugate() that return value when you
happen to be dealing with complex values; I'm not sure.
--
Robert Kern
rkern at ucsd.edu
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter
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