Hello, I was doing some computation involving finding nullspace of a matrix with only \pm 1 entries when right_kernel().basis() started giving me nullvectors...
Here is a minimal example to reproduce the behaviour: ================ import numpy as np r=10 c=76 A = 2*np.random.randint(2, size=(r,c))-np.ones((r,c),dtype=np.int) A = matrix(QQ,A) print A.right_kernel().dimension()+A.rank() B = A.right_kernel().basis() print B[-1] ================ Sage 4.7.2 on 64 bit Fedora 16 linux (compiled from source) gives me: $ sage minex.sage 86 (0, 0, 0, 0, 0, 0, 0, ... lots of zeros...., 0, 0, 0, 0, 0, 0, 0) while sage 4.7 on 32 bit osx (downloaded binary) gives: $ sage minex.sage 76 (0, 0, 0, 0, 0, ..lots of zeros... , 0, 0, 2, -1, 2, 4, -1, 3, -1, -3, 0, -2, 1) sage 4.7.2 on 64 bit osx behaves as the linux version. When the number of columns in the matrix is less than 76 I can't reproduce the error, and when the number of rows is less than 10 it only happens sometimes. Also removing "dtype=np.int", so that the dtype of the numpy matrix is the default float64, makes the error go away. Any ideas what is happening? Thanks, -- Vegard Lima -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
