DTPTRS(3)
solves a triangular system of the form A * X = B or A**T * X = B,
SYNOPSIS
 SUBROUTINE DTPTRS(

UPLO, TRANS, DIAG, N, NRHS, AP, B, LDB, INFO )

CHARACTER
DIAG, TRANS, UPLO

INTEGER
INFO, LDB, N, NRHS

DOUBLE
PRECISION AP( * ), B( LDB, * )
PURPOSE
DTPTRS solves a triangular system of the form
where A is a triangular matrix of order N stored in packed format,
and B is an NbyNRHS 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 = Transpose)
 DIAG (input) CHARACTER*1

= 'N': A is nonunit 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) DOUBLE PRECISION array, dimension (N*(N+1)/2)

The upper or lower triangular matrix A, packed columnwise in
a linear array. The jth column of A is stored in the array
AP as follows:
if UPLO = 'U', AP(i + (j1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j1)*(2*nj)/2) = A(i,j) for j<=i<=n.
 B (input/output) DOUBLE PRECISION 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 ith argument had an illegal value
> 0: if INFO = i, the ith diagonal element of A is zero,
indicating that the matrix is singular and the
solutions X have not been computed.