Public Member Functions
subroutine	eigensym2 (em, vv, oo)
	Get the orthogonal eigenvectors, vv, and diagonal matrix of eigenvalues, oo, of the symmetric 2*2 matrix, em.

subroutine	eigensym2d (em, vv, oo, vvd, ood, ff)
	For a symmetric 2*2 matrix, em, return the normalized eigenvectors, vv, and the diagonal matrix of eigenvalues, oo.

Detailed Description

Definition at line 21 of file psym2.f90.

Constructor & Destructor Documentation

◆ eigensym2()

subroutine psym2::eigensym2::eigensym2	(	real(dp), dimension(2,2), intent(in)	em,
		real(dp), dimension(2,2), intent(out)	vv,
		real(dp), dimension(2,2), intent(out)	oo )

Get the orthogonal eigenvectors, vv, and diagonal matrix of eigenvalues, oo, of the symmetric 2*2 matrix, em.

Parameters

[in]	em	symmetric 2*2 matrix
[out]	vv	orthogonal eigenvectors
[out]	oo	diagonal matrix of eigenvalues

Author: R. J. Purser

Definition at line 42 of file psym2.f90.

References pietc::o2, pietc::u0, and pietc::u1.

Member Function/Subroutine Documentation

◆ eigensym2d()

subroutine psym2::eigensym2::eigensym2d	(	real(dp), dimension(2,2), intent(in)	em,
		real(dp), dimension(2,2), intent(out)	vv,
		real(dp), dimension(2,2), intent(out)	oo,
		real(dp), dimension(2,2,2,2), intent(out)	vvd,
		real(dp), dimension(2,2,2,2), intent(out)	ood,
		logical, intent(out)	ff )

For a symmetric 2*2 matrix, em, return the normalized eigenvectors, vv, and the diagonal matrix of eigenvalues, oo.

If the two eigenvalues are equal, proceed no further and raise the logical failure flag, ff, to .true.; otherwise, return with vvd=d(vv)/d(em) and ood=d(oo)/d(em) and ff=.false., and maintain the symmetries between the last two of the indices of these derivatives.