Matrix trace

[Jonas Glesaaen]

Hi again,

Another common linalg operation I cannot find is the trace of a matrix. It would be great to have that function as well.

Cheers, Jonas Glesaaen

[Klaus Iglberger]

Hi Jonas!

Unfortunately, Blaze currently does not provide the feature to compute the trace of a matrix. However, without giving any promise, we might be able to add this feature to the upcoming 3.1 release. Thanks for the great suggestion,

Best regards,

Klaus!

[Klaus Iglberger]

Summary

The feature has been implemented, tested, optimized and documented as required. It is immediately available via cloning the Blaze repository and will be officially released in Blaze 3.1.

Computing the trace of a matrix

The trace() function sums the diagonal elements of a square dense or sparse matrix:

blaze::StaticMatrix<int,3UL,3UL> A{ { -1,  2, -3 }
                                  , { -4, -5,  6 }
                                  , {  7, -8, -9 } };

trace( A );  // Returns the sum of the diagonal elements, i.e. -15

In case the given matrix is not a square matrix, a std::invalid_argument exception is thrown.