I'm having trouble making use of the block_matrix function. I can't even recreate simple examples from the block_matrix documentation, for example
sage: A = matrix(QQ, 2, 2, [3,9,6,10])
sage: X=block_matrix([ [A, -A], [~A, 100*A] ])
I receive the error "Must specify rows or cols for non-square block matrix." When I attempt to set those dimensions I continue to get errors.
(My actual application of this is a bit more complicated, but the dimensions all work out. And I have used block_matrix in another program with symbolic entries. I must have gotten lucky.)
I did not import numpy, I did not believe it was necessary. But there's no difference when I do.
Thanks in advance to this magnificent community of sage-masters.