cgtsv.f (3)  Linux Man Pages
NAME
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 (integerN, integerNRHS, complex, dimension( * )DL, complex, dimension( * )D, complex, dimension( * )DU, complex, dimension( ldb, * )B, integerLDB, integerINFO)
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 NbyN 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.
NRHSNRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
DLDL is COMPLEX array, dimension (N1) On entry, DL must contain the (n1) subdiagonal elements of A. On exit, DL is overwritten by the (n2) elements of the second superdiagonal of the upper triangular matrix U from the LU factorization of A, in DL(1), ..., DL(n2).
DD 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.
DUDU is COMPLEX array, dimension (N1) On entry, DU must contain the (n1) superdiagonal elements of A. On exit, DU is overwritten by the (n1) elements of the first superdiagonal of U.
BB is COMPLEX array, dimension (LDB,NRHS) On entry, the NbyNRHS right hand side matrix B. On exit, if INFO = 0, the NbyNRHS solution matrix X.
LDBLDB is INTEGER The leading dimension of the array B. LDB >= max(1,N).
INFOINFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith 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:
 September 2012
Definition at line 125 of file cgtsv.f.
Author
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