ztptrs(3F)

NAME
     ZTPTRS - solve a triangular system of the form   A * X = B, A**T * X = B,
     or A**H * X = B,

SYNOPSIS
     SUBROUTINE ZTPTRS( UPLO, TRANS, DIAG, N, NRHS, AP, B, LDB, INFO )

         CHARACTER      DIAG, TRANS, UPLO

         INTEGER        INFO, LDB, N, NRHS

         COMPLEX*16     AP( * ), B( LDB, * )

PURPOSE
     ZTPTRS solves a triangular system of the form

     where A is a triangular matrix of order N stored in packed format, and B
     is an N-by-NRHS matrix.  A check is made to verify that A is nonsingular.


ARGUMENTS
     UPLO    (input) CHARACTER*1
             = 'U':  A is upper triangular;
             = 'L':  A is lower triangular.

     TRANS   (input) CHARACTER*1
             Specifies the form of the system of equations:
             = 'N':  A * X = B     (No transpose)
             = 'T':  A**T * X = B  (Transpose)
             = 'C':  A**H * X = B  (Conjugate transpose)

     DIAG    (input) CHARACTER*1
             = 'N':  A is non-unit triangular;
             = 'U':  A is unit triangular.

     N       (input) INTEGER
             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.

     AP      (input) COMPLEX*16 array, dimension (N*(N+1)/2)
             The upper or lower triangular 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)*(2*n-j)/2) = A(i,j) for j<=i<=n.

     B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
             On entry, the right hand side matrix B.  On exit, if INFO = 0,
             the 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 i-th diagonal element of A is zero,
             indicating that the matrix is singular and the solutions X have
             not been computed.