ctptrs-f(3)

ctptrs.f –

Synopsis

Functions/Subroutines

subroutine ctptrs (UPLO, TRANS, DIAG, N, NRHS, AP, B, LDB, INFO)
CTPTRS

Function/Subroutine Documentation

subroutine ctptrs (characterUPLO, characterTRANS, characterDIAG, integerN, integerNRHS, complex, dimension( * )AP, complex, dimension( ldb, * )B, integerLDB, integerINFO)

CTPTRS

Purpose:

 CTPTRS solves a triangular system of the form
 A * X = B, A**T * X = B, or A**H * X = B,
 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.

Parameters:

UPLO

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

TRANS

 TRANS is 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

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

 N is INTEGER
 The order of the matrix A. N >= 0.

NRHS

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

 AP is COMPLEX 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 is COMPLEX array, dimension (LDB,NRHS)
 On entry, the right hand side matrix B.
 On exit, if INFO = 0, the solution matrix X.

LDB

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

INFO

 INFO is 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.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 131 of file ctptrs.f.

Author

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