Re: [sage-support] Re: Strange interaction between sage and numpy
On Sun, Jan 8, 2012 at 6:23 PM, Volker Braun vbraun.n...@gmail.com wrote: Just noticed the following: sage: import numpy as np sage: r=10 sage: c=76 sage: A = 2*np.random.randint(2, size=(r,c))-np.ones((r,c),dtype=np.int) sage: A = matrix(QQ,A) sage: A 10 x 76 dense matrix over Integer Ring (type 'print A.str()' to see all of the entries) So matrix(QQ,numpy) actually constructs a matrix over ZZ. Thats somewhat unexpected. Ok, I saw that you opened a ticket for the right_kernel thing: http://trac.sagemath.org/sage_trac/ticket/12280 Should I create a new ticket for this matrix(QQ,numpy) thing? 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
Re: [sage-support] Re: Strange interaction between sage and numpy
Sure! I suspect it would be relatively easy to fix in sage/matrix/constructor.py if you want to give it a try! But in any case please open a ticket. -- 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
Re: [sage-support] Re: Strange interaction between sage and numpy
Created this ticket for the numpy array to matrix issue: http://trac.sagemath.org/sage_trac/ticket/12287 On Mon, Jan 9, 2012 at 4:20 PM, Volker Braun vbraun.n...@gmail.com wrote: Sure! I suspect it would be relatively easy to fix in sage/matrix/constructor.py if you want to give it a try! But in any case please open a ticket. 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
[sage-support] Re: Strange interaction between sage and numpy
It's hard to say whether it's a linear algebra bug, or matrix creation bug. Could you check that the result of A = matrix(QQ,A) actually makes sense? -- 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
Re: [sage-support] Re: Strange interaction between sage and numpy
On Sun, Jan 8, 2012 at 9:12 AM, Dima Pasechnik dimp...@gmail.com wrote: It's hard to say whether it's a linear algebra bug, or matrix creation bug. Could you check that the result of A = matrix(QQ,A) actually makes sense? It looks ok to me: sage: A = matrix(QQ,A) sage: A 10 x 76 dense matrix over Integer Ring (type 'print A.str()' to see all of the entries) sage: A.str() '[ 1 -1 1 1 1 1 -1 -1 1 -1 1 -1 1 -1 -1 -1 1 -1 1 -1 -1 -1 etc etc... The thing is that the A.right_kernel_matrix() is padded with zeros. It has rank - (dim null space) extra zero columns. The first dim null space columns are correctly computed. 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
Re: [sage-support] Re: Strange interaction between sage and numpy
I looked into it a bit and it seems to be an IML bug. Presumably 75 is some cutoff inside IML, though I haven't verified this. You get the right answer if you use a different backend to compute the kernel: sage: matrix(QQ,A).right_kernel(algorithm='generic').dimension()+A.rank() 76 -- 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
Re: [sage-support] Re: Strange interaction between sage and numpy
Just noticed the following: sage: import numpy as np sage: r=10 sage: c=76 sage: A = 2*np.random.randint(2, size=(r,c))-np.ones((r,c),dtype=np.int) sage: A = matrix(QQ,A) sage: A 10 x 76 dense matrix over Integer Ring (type 'print A.str()' to see all of the entries) So matrix(QQ,numpy) actually constructs a matrix over ZZ. Thats somewhat unexpected. -- 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
