MatrixOptions

pagan — Mon, 29 Jun 2009 17:56:23 Z

There is a command to show the underlying storage of a Matrix.

> M := Matrix(100,100,'storage'='sparse'):

> MatrixOptions(M,'storage');
                                    sparse

There are also ways to see the exact number of stored entries.

> N := Matrix(100,100):

> rtable_num_elems(N,'Stored');
                                     10000
 
> M := Matrix(100,100,'storage'='sparse'):

> rtable_num_elems(M,'Stored');
                                       0

> M[3,3]:=1.0:
> rtable_num_elems(M,'Stored');
                                       1

That error message with HWcall[1] looks like a bug. You could report it. If you post it then someone might suggest a workaround.

MaplePrimes - answers and comments on Question, using the spare storage option for matrix

MatrixOptions