densematrixmodule::solveeigenvalues Interface Reference

Solves an eigenvalue problem. More...

Public Member Functions
subroutine	solveeigenvaluea (A, lambda, Z, n, nVal, nVec, ierr)
	Solves a symmetric-definite eigenvalue problem. More...
subroutine	solveeigenvalueb (A, B, lambda, Z, n, nVal, nVec, ierr)
	Solves a generalized symmetric-definite eigenvalue problem. More...

Detailed Description

Solves an eigenvalue problem.

Member Function/Subroutine Documentation

solveeigenvaluea()

subroutine densematrixmodule::solveeigenvalues::solveeigenvaluea	(	real(dp), dimension(:,:), intent(inout)	A,
		real(dp), dimension(:), intent(out)	lambda,
		real(dp), dimension(:,:), intent(out)	Z,
		integer, intent(in)	n,
		integer, intent(in)	nVal,
		integer, intent(in)	nVec,
		integer, intent(out)	ierr
	)

Solves a symmetric-definite eigenvalue problem.

Parameters

	A	Dense coefficient matrix
[out]	lambda	Computed eigenvalues
[out]	Z	Computed eigenvectors
[in]	n	Dimension of the eigenvalue problem
[in]	nVal	Number of eigenvalues to solve for
[in]	nVec	Number of eigenvectors to solve for
[out]	ierr	Error flag

The eigenvalues and (optionally) the associated eigenvectors of the symmetric-definite eigenproblem A*x - λx = 0 is computed using LAPACK::DSYEVX, where A is a dense symmetric matrix.

Author

Knut Morten Okstad

Date

5 Jul 2021

solveeigenvalueb()

subroutine densematrixmodule::solveeigenvalues::solveeigenvalueb	(	real(dp), dimension(:,:), intent(inout)	A,
		real(dp), dimension(:,:), intent(inout)	B,
		real(dp), dimension(:), intent(out)	lambda,
		real(dp), dimension(:,:), intent(out), target	Z,
		integer, intent(in)	n,
		integer, intent(in)	nVal,
		integer, intent(in)	nVec,
		integer, intent(out)	ierr
	)

Solves a generalized symmetric-definite eigenvalue problem.

Parameters

	A	Dense stiffness matrix
	B	Dense or diagonal mass matrix
[out]	lambda	Computed eigenvalues
[out]	Z	Computed eigenvectors
[in]	n	Dimension of the eigenvalue problem
[in]	nVal	Number of eigenvalues to solve for
[in]	nVec	Number of eigenvectors to solve for
[out]	ierr	Error flag

The eigenvalues and (optionally) the associated eigenvectors of the generalized symmetric-definite eigenproblem A*x - λ*B*x = 0 is computed using LAPACK::DSYGVX, where A and B are dense matrices. If B is a diagonal matrix, the eigenvalue problem is transformed into the form A*x - λ*I*x = 0 where I is the identity matrix, and is solved using the LAPACK::DSYEVX subroutine instead.

Author

Knut Morten Okstad

Date

8 Apr 2011

---

The documentation for this interface was generated from the following file:

• src/vpmUtilities/denseMatrixModule.f90