sgtsl

NAME

sgtsl - (obsolete) solve the linear system Ax = b for a tridiagonal matrix A and vectors b and x.

SYNOPSIS

  SUBROUTINE SGTSL( N, SUB, DIAG, SUPER, B, INFO)
  INTEGER N, INFO
  REAL SUB(*), DIAG(*), SUPER(*), B(*)
 
  SUBROUTINE SGTSL_64( N, SUB, DIAG, SUPER, B, INFO)
  INTEGER*8 N, INFO
  REAL SUB(*), DIAG(*), SUPER(*), B(*)

C INTERFACE

#include <sunperf.h>

void sgtsl(int n, float *sub, float *diag, float *super, float *b, int *info);

void sgtsl_64(long n, float *sub, float *diag, float *super, float *b, long *info);

ARGUMENTS

* N (input)

Order of the matrix A. N >= 0.

* SUB (input)

Subdiagonal of A. SUB(2) through SUB(N) contain the subdiagonal and SUB(1) is not referenced.

* DIAG (input)

Diagonal of A.

* SUPER (input)

Superdiagonal of A. SUPER(1) through SUPER(N-1) contain the superdiagonal and SUPER(N) is not referenced.

* B (input/output)

On entry, the right-hand side vector b. On exit, the solution vector x.

* INFO (output)

On exit:

INFO = 0 Subroutine completed normally.

INFO < 0 Returns a value k when the kth element of the diagonal becomes exactly zero.