chpgst-f(3)

chpgst.f –

Synopsis

Functions/Subroutines

subroutine chpgst (ITYPE, UPLO, N, AP, BP, INFO)
CHPGST

Function/Subroutine Documentation

subroutine chpgst (integerITYPE, characterUPLO, integerN, complex, dimension( * )AP, complex, dimension( * )BP, integerINFO)

CHPGST

Purpose:

 CHPGST reduces a complex Hermitian-definite generalized
 eigenproblem to standard form, using packed storage.
 If ITYPE = 1, the problem is A*x = lambda*B*x,
 and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H)
 If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or
 B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H*A*L.
 B must have been previously factorized as U**H*U or L*L**H by CPPTRF.

 

Parameters:

ITYPE

 ITYPE is INTEGER
 = 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H);
 = 2 or 3: compute U*A*U**H or L**H*A*L.

UPLO

 UPLO is CHARACTER*1
 = 'U': Upper triangle of A is stored and B is factored as
 U**H*U;
 = 'L': Lower triangle of A is stored and B is factored as
 L*L**H.

N

 N is INTEGER
 The order of the matrices A and B. N >= 0.

AP

 AP is COMPLEX array, dimension (N*(N+1)/2)
 On entry, the upper or lower triangle of the Hermitian matrix
 A, packed columnwise in a linear array. The j-th column of A
 is stored in the array AP as follows:
 if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
 if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
 On exit, if INFO = 0, the transformed matrix, stored in the
 same format as A.

BP

 BP is COMPLEX array, dimension (N*(N+1)/2)
 The triangular factor from the Cholesky factorization of B,
 stored in the same format as A, as returned by CPPTRF.

INFO

 INFO is INTEGER
 = 0: successful exit
 < 0: if INFO = -i, the i-th argument had an illegal value

 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 114 of file chpgst.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.