[Numpy-discussion] Possible bug in linalg.matrix_rank

[alex]

On Thu, May 22, 2014 at 1:50 PM, Darlan Cavalcante Moreira
<darcamo at gmail.com> wrote:
>
> After updating Ubuntu to 14.04 and thus numpy to version 1.8.1 I'm
> having problems with the linalg.matrix_rank function that I didn't have
> before (as far as I know).
>
> More specifically, I get the error
> "TypeError: No loop matching the specified signature was found for ufunc svd_m"
> when I try to calculate the rank of a non-square complex matrix, but it does not
> happen for any non-square matrix.
>
>
> Below you can find the cases tyhat work and the case that doesn't work.
>
> --8<---------------cut here---------------start------------->8---
> # Real matrices
> A = np.random.randn(3,3);
> A = np.random.randn(4,3);
> A = np.random.randn(3,4);
> np.linalg.matrix_rank(A) # Works for any of the previous 'A' matrices
>
> # Complex matrices
> A = np.random.randn(3,3) + 1j*np.random.randn(3,3);
> A = np.random.randn(4,3) + 1j*np.random.randn(4,3);
> np.linalg.matrix_rank(A) # Works for any of the previous 'A' matrices
>
> # For the matrix below I get the error
> A = np.random.randn(3,4) + 1j*np.random.randn(3,4);
> np.linalg.matrix_rank(A) # Does not work and gives me the TypeError
> --8<---------------cut here---------------end--------------->8---
>
>
> --
> Darlan Cavalcante Moreira
> darcamo at gmail.com
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This regression should now be fixed in the numpy development version.