
 
 Purpose
 =======
 
    LA_PPSV computes the solution to a linear system of equations 
 A*X = B, where A is real symmetric or complex Hermitian and, in either
 case, positive definite, and where X and B are rectangular matrices or
 vectors. A is stored in packed format. 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 (L = U^H ). The factored form of A is then used to solve the 
 above system.
 
 =========
 
       SUBROUTINE LA_PPSV( AP, B, UPLO=uplo, INFO=info )
           <type>(<wp>), INTENT(INOUT) :: AP(:), <rhs>
           CHARACTER(LEN=1), INTENT(IN), OPTIONAL :: UPLO
           INTEGER, INTENT(OUT), OPTIONAL :: INFO
       where
           <type> ::= REAL | COMPLEX
           <wp>   ::= KIND(1.0) | KIND(1.0D0)
           <rhs>  ::= B(:,:) | B(:)
 
 Arguments
 =========
 
 AP      (input/output) REAL or COMPLEX array, shape (:) with size(AP) 
         = n*(n+1)/2, where n is the order of A.
         On entry, the upper or lower triangle of matrix A in packed
         storage. The elements are stored columnwise as follows:
         if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j<=n;
         if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for 1<=j<=i<=n.
         On exit, the factor U or L from the Cholesky factorization 
 	 A = U^H*U or A = L*L^H , in the same storage format as A.
 B       (input/output) REAL or COMPLEX array, shape (:,:) with 
         size(B,1) = n or shape (:) with size(B) = n.
         On entry, the matrix B.
         On exit, the solution matrix X.
 UPLO    Optional, (input) CHARACTER(LEN=1)
         = 'U': Upper triangle of A is stored;
         = 'L': Lower triangle of A is stored.
         Default value: 'U'.
 INFO    Optional (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 could not be computed.
         If INFO is not present and an error occurs, then the program is
         terminated with an error message.

