cposv(3F)

NAME
     CPOSV - compute the solution to a complex system of linear equations  A *
     X = B,

SYNOPSIS
     SUBROUTINE CPOSV( UPLO, N, NRHS, A, LDA, B, LDB, INFO )

         CHARACTER     UPLO

         INTEGER       INFO, LDA, LDB, N, NRHS

         COMPLEX       A( LDA, * ), B( LDB, * )

PURPOSE
     CPOSV computes the solution to a complex system of linear equations
        A * X = B, where A is an N-by-N Hermitian positive definite matrix and
     X and B are N-by-NRHS matrices.

     The Cholesky decomposition is used to factor A as
        A = U**H* U,  if UPLO = 'U', or
        A = L * L**H,  if UPLO = 'L',
     where U is an upper triangular matrix and  L is a lower triangular
     matrix.  The factored form of A is then used to solve the system of
     equations A * X = B.


ARGUMENTS
     UPLO    (input) CHARACTER*1
             = 'U':  Upper triangle of A is stored;
             = 'L':  Lower triangle of A is stored.

     N       (input) INTEGER
             The number of linear equations, i.e., the order of the matrix A.
             N >= 0.

     NRHS    (input) INTEGER
             The number of right hand sides, i.e., the number of columns of
             the matrix B.  NRHS >= 0.

     A       (input/output) COMPLEX array, dimension (LDA,N)
             On entry, the Hermitian matrix A.  If UPLO = 'U', the leading N-
             by-N upper triangular part of A contains the upper triangular
             part of the matrix A, and the strictly lower triangular part of A
             is not referenced.  If UPLO = 'L', the leading N-by-N lower
             triangular part of A contains the lower triangular part of the
             matrix A, and the strictly upper triangular part of A is not
             referenced.

             On exit, if INFO = 0, the factor U or L from the Cholesky
             factorization A = U**H*U or A = L*L**H.
     LDA     (input) INTEGER
             The leading dimension of the array A.  LDA >= max(1,N).

     B       (input/output) COMPLEX array, dimension (LDB,NRHS)
             On entry, the N-by-NRHS right hand side matrix B.  On exit, if
             INFO = 0, the N-by-NRHS solution matrix X.

     LDB     (input) INTEGER
             The leading dimension of the array B.  LDB >= max(1,N).

     INFO    (output) INTEGER
             = 0:  successful exit
             < 0:  if INFO = -i, the i-th argument had an illegal value
             > 0:  if INFO = i, the leading minor of order i of A is not
             positive definite, so the factorization could not be completed,
             and the solution has not been computed.