cgtsv.f man page

cgtsv.f

Synopsis

Functions/Subroutines

subroutine cgtsv (N, NRHS, DL, D, DU, B, LDB, INFO)
CGTSV computes the solution to system of linear equations A * X = B for GT matrices

Function/Subroutine Documentation

subroutine cgtsv (integer N, integer NRHS, complex, dimension( * ) DL, complex, dimension( * ) D, complex, dimension( * ) DU, complex, dimension( ldb, * ) B, integer LDB, integer INFO)

CGTSV computes the solution to system of linear equations A * X = B for GT matrices  

Purpose:

 CGTSV  solves the equation

    A*X = B,

 where A is an N-by-N tridiagonal matrix, by Gaussian elimination with
 partial pivoting.

 Note that the equation  A**T *X = B  may be solved by interchanging the
 order of the arguments DU and DL.
Parameters:

N

          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.

DL

          DL is COMPLEX array, dimension (N-1)
          On entry, DL must contain the (n-1) subdiagonal elements of
          A.
          On exit, DL is overwritten by the (n-2) elements of the
          second superdiagonal of the upper triangular matrix U from
          the LU factorization of A, in DL(1), ..., DL(n-2).

D

          D is COMPLEX array, dimension (N)
          On entry, D must contain the diagonal elements of A.
          On exit, D is overwritten by the n diagonal elements of U.

DU

          DU is COMPLEX array, dimension (N-1)
          On entry, DU must contain the (n-1) superdiagonal elements
          of A.
          On exit, DU is overwritten by the (n-1) elements of the first
          superdiagonal of U.

B

          B is COMPLEX array, dimension (LDB,NRHS)
          On entry, the N-by-NRHS right hand side matrix B.
          On exit, if INFO = 0, the N-by-NRHS 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, U(i,i) is exactly zero, and the solution
                has not been computed.  The factorization has not been
                completed unless i = N.
Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 126 of file cgtsv.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page cgtsv(3) is an alias of cgtsv.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK