On Mon, Feb 28, 2011 at 11:12 AM, Stephen Hartke <har...@gmail.com> wrote:
> Assignment of a matrix to a matrix slice works as expected except for when
> the slice is 1x1; in that case, Sage expects a scalar instead of a 1x1
> matrix.
I think this has changed very recently. Your code seems to work in
4.6.2.rc0, but not in 4.6.1. You can actually crash Sage 4.6.1 pretty
hard doing this -- most fields simply return an error, but SR doesn't,
and that leads to trouble, at least for me:
sage: A = matrix(SR, 2, 2, range(4))
sage: A[0:1, 0:1] = A[0:1, 0:1] # takes several seconds but finally agrees
sage: A
[[0] 1]
[ 2 3]
sage: A[0,0], type(A[0,0]), parent(A[0,0])
([0], <type 'sage.symbolic.expression.Expression'>, Symbolic Ring)
sage: A[0,0] in SR
terminate called after throwing an instance of 'std::runtime_error'
what(): Number_T::hash() python function (__hash__) raised exception
/Applications/sage/local/bin/sage-sage: line 300: 41613 Abort trap
sage-ipython "$@" -i
Doug
--
Department of Earth Sciences
University of Hong Kong
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