Additional testing / feedback for the proposed rank and basis grading code would be appreciated.
See: https://github.com/openwebwork/pg/issues/409
For the problem Library/NAU/setLinearAlgebra/expandBasis.pg
Under WeBWorK 2.15, and with random seed 1253, I get the error "Your answer isn't a matrix, it looks like a list of lists of numbers".
Somehow replacing the default rank.pl with Nathan's rank.pl fixes the problem.
(Thank you, Nathan!)
This does not happen with the next release of WeBWorK/PG (currently in "almost" release candidate stage).
OK, great, thanks!