chpgst.f - Man Page

SRC/chpgst.f

Synopsis

Functions/Subroutines

subroutine chpgst (itype, uplo, n, ap, bp, info)
CHPGST

Function/Subroutine Documentation

subroutine chpgst (integer itype, character uplo, integer n, complex, dimension( * ) ap, complex, dimension( * ) bp, integer info)

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.

Definition at line 112 of file chpgst.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page chpgst(3) is an alias of chpgst.f(3).

Tue Nov 28 2023 12:08:41 Version 3.12.0 LAPACK