Problem with the transpose of SymMat

[leo-bart]

I'm using a symmatric matrix to perform a rotation of a 6x6 stiffness matrix like this:

SqrMat3 rotateY = BasicRotAIKy(phi);
SymMat randomRotationMatrix (6,EYE);
for (unsigned ri=0;ri<=2;ri++){
	for (unsigned rj=0;rj<=i;rj++){
		randomRotationMatrix(ri,rj) = rotateY(ri,rj);
		randomRotationMatrix(ri+3,rj+3) = rotateY(ri,rj);
		}
	}

SymMat rotatedStiffness(6,INIT,0.0);
rotatedStiffness = trans(randomRotationMatrix) * stiffnessMatrix * randomRotationMatrix;

This is a rather old code of mine: I've been using it this way for three years now, but when I compile against fmatvec commit 3c41097 I get the following error:

/usr/local/include/fmatvec/linear_algebra.h:1391:78: error: ‘const class fmatvec::Matrix<fmatvec::Symmetric, fmatvec::Ref, fmatvec::Ref, double>’ has no member named ‘T’
 1391 |   Matrix<Type,Col,Row,AT> trans(const Matrix<Type,Row,Col,AT> &A) { return A.T(); }
      |                                                                            ~~^

Is this a bug or the transpose of symmetric matrices is not currently supported?

[foerg]

As transpose has no effect on symmetric matrices it was removed to prevent the user of applying an unnecessary operation. Do you really need the transpose operator for SymMat?
I would recommend to omit trans in your operation or to use the function JTMJ:
rotatedStiffness = JTMJ(stiffnessMatrix, randomRotationMatrix);

[leo-bart]

As matter of fact no, I don't need the transpose. I copied the code from another place (probably some old Matlab code) and did not put much thinking on it. Indeed now, looking at the code I realized it is wrong because I'm symmetrizing a non symmetric matrix. I'll correct it.

Thank you for informing the JTMJ function! I did not know it.

I'll close the issue.