MFsym_eigenvalues MDsym_eigenvalues MEsym_eigenvalues
 Function Eigenvalues and/or Eigenvectors of a real symmetric matrix
 Syntax C/C++ #include int MFsym_eigenvalues( fVector EigVals, fMatrix EigVecs, fMatrix MA, ui len, int CalcEigenVec ); C++ MatObj #include int matrix::sym_eigenvalues( matrix EigVecs, const matrix& MA, int CalcEigenVec ); int matrix::sym_eigenvalues( matrix* EigVecs, const matrix& MA, int CalcEigenVec ); Pascal/Delphi uses MFstd; function MFsym_eigenvalues( EigVals:fVector; EigVecs, MA:fMatrix; len:UIntSize; CalcEigenVec:IntBool ): IntBool;
 Description The eigenvalues, with or without the eigenvectors, of MA are calculated. This function is for non-singular symmetric real matrices only! It takes the following arguments: EigVals: a vector in which the eigenvalues will be returned EigVecs: a matrix of size len*len. If the eigenvectors are desired, the routine will fill the columns of EigVecs with the eigenvectors; otherwise, EigVecs is just needed as workspace. MA: the input matrix, which may or may not be overwritten by EigVecs len: the length of the rows (which is the same as the height of the columns, as MA must be a symmetric square matrix) CalcEigenVec: an int or IntBool, deciding if only the eigenvalues are needed (CalcEigenVec = FALSE or 0), or if the eigenvectors are desired as well (CalcEigenVec = TRUE or 1). Calculating the eigenvalues alone, without the eigenvectors, can speed up the calculation by up to a factor of two. The eigenvalues (and eigenvectors) are returned in no specific order.
 Return value FALSE (0), if no error occurred, otherwise TRUE (non-zero). It is highly recommended to check the return value, as deficiencies of the input matrix usually are not known beforehand, but would lead to failure of this function.