zgttrs (3)

Functions/Subroutines

subroutine zgttrs (TRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB, INFO)

ZGTTRS

subroutine zgttrs (characterTRANS, integerN, integerNRHS, complex*16, dimension( * )DL, complex*16, dimension( * )D, complex*16, dimension( * )DU, complex*16, dimension( * )DU2, integer, dimension( * )IPIV, complex*16, dimension( ldb, * )B, integerLDB, integerINFO)

ZGTTRS

Purpose:

 ZGTTRS solves one of the systems of equations
    A * X = B,  A**T * X = B,  or  A**H * X = B,
 with a tridiagonal matrix A using the LU factorization computed
 by ZGTTRF.

Parameters:

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)

N

          N is INTEGER
          The order of the matrix A.

NRHS

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

DL

          DL is COMPLEX*16 array, dimension (N-1)
          The (n-1) multipliers that define the matrix L from the
          LU factorization of A.

D

          D is COMPLEX*16 array, dimension (N)
          The n diagonal elements of the upper triangular matrix U from
          the LU factorization of A.

DU

          DU is COMPLEX*16 array, dimension (N-1)
          The (n-1) elements of the first super-diagonal of U.

DU2

          DU2 is COMPLEX*16 array, dimension (N-2)
          The (n-2) elements of the second super-diagonal of U.

IPIV

          IPIV is INTEGER array, dimension (N)
          The pivot indices; for 1 <= i <= n, row i of the matrix was
          interchanged with row IPIV(i).  IPIV(i) will always be either
          i or i+1; IPIV(i) = i indicates a row interchange was not
          required.

B

          B is COMPLEX*16 array, dimension (LDB,NRHS)
          On entry, the matrix of right hand side vectors B.
          On exit, B is overwritten by the solution vectors 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 = -k, the k-th argument had an illegal value

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 138 of file zgttrs.f.

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