zptts2

NAME

zptts2 - solve a tridiagonal system of the form A * X = B using the factorization A = U'*D*U or A = L*D*L' computed by CPTTRF

SYNOPSIS

  SUBROUTINE ZPTTS2( IUPLO, N, NRHS, D, E, B, LDB)
  DOUBLE COMPLEX E(*), B(LDB,*)
  INTEGER IUPLO, N, NRHS, LDB
  DOUBLE PRECISION D(*)
 
  SUBROUTINE ZPTTS2_64( IUPLO, N, NRHS, D, E, B, LDB)
  DOUBLE COMPLEX E(*), B(LDB,*)
  INTEGER*8 IUPLO, N, NRHS, LDB
  DOUBLE PRECISION D(*)

F95 INTERFACE

  SUBROUTINE ZPTTS2( IUPLO, N, NRHS, D, E, B, [LDB])
  COMPLEX(8), DIMENSION(:) :: E
  COMPLEX(8), DIMENSION(:,:) :: B
  INTEGER :: IUPLO, N, NRHS, LDB
  REAL(8), DIMENSION(:) :: D
 
  SUBROUTINE ZPTTS2_64( IUPLO, N, NRHS, D, E, B, [LDB])
  COMPLEX(8), DIMENSION(:) :: E
  COMPLEX(8), DIMENSION(:,:) :: B
  INTEGER(8) :: IUPLO, N, NRHS, LDB
  REAL(8), DIMENSION(:) :: D

C INTERFACE

#include <sunperf.h>

void zptts2(int iuplo, int n, int nrhs, double *d, doublecomplex *e, doublecomplex *b, int ldb);

void zptts2_64(long iuplo, long n, long nrhs, double *d, doublecomplex *e, doublecomplex *b, long ldb);

PURPOSE

zptts2 solves a tridiagonal system of the form A * X = B using the factorization A = U'*D*U or A = L*D*L' computed by CPTTRF. D is a diagonal matrix specified in the vector D, U (or L) is a unit bidiagonal matrix whose superdiagonal (subdiagonal) is specified in the vector E, and X and B are N by NRHS matrices.

ARGUMENTS

* IUPLO (input): Specifies the form of the factorization and whether the vector E is the superdiagonal of the upper bidiagonal factor U or the subdiagonal of the lower bidiagonal factor L.
* N (input): The order of the tridiagonal matrix A. N >= 0.
* NRHS (input): The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
* D (input): The n diagonal elements of the diagonal matrix D from the factorization A = U'*D*U or A = L*D*L'.
* E (input): If IUPLO = 1, the (n-1) superdiagonal elements of the unit bidiagonal factor U from the factorization A = U'*D*U. If IUPLO = 0, the (n-1) subdiagonal elements of the unit bidiagonal factor L from the factorization A = L*D*L'.
* B (input/output): On entry, the right hand side vectors B for the system of linear equations. On exit, the solution vectors, X.
* LDB (input): The leading dimension of the array B. LDB >= max(1,N).