# sgtt02.f - Man Page

TESTING/LIN/sgtt02.f

## Synopsis

### Functions/Subroutines

subroutine sgtt02 (trans, n, nrhs, dl, d, du, x, ldx, b, ldb, resid)
SGTT02

## Function/Subroutine Documentation

### subroutine sgtt02 (character trans, integer n, integer nrhs, real, dimension( * ) dl, real, dimension( * ) d, real, dimension( * ) du, real, dimension( ldx, * ) x, integer ldx, real, dimension( ldb, * ) b, integer ldb, real resid)

SGTT02

Purpose:

``` SGTT02 computes the residual for the solution to a tridiagonal
system of equations:
RESID = norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS),
where EPS is the machine epsilon.
The norm used is the 1-norm.```
Parameters

TRANS

```          TRANS is CHARACTER
Specifies the form of the residual.
= 'N':  B - A    * X  (No transpose)
= 'T':  B - A**T * X  (Transpose)
= 'C':  B - A**H * X  (Conjugate transpose = Transpose)```

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 matrices B and X.  NRHS >= 0.```

DL

```          DL is REAL array, dimension (N-1)
The (n-1) sub-diagonal elements of A.```

D

```          D is REAL array, dimension (N)
The diagonal elements of A.```

DU

```          DU is REAL array, dimension (N-1)
The (n-1) super-diagonal elements of A.```

X

```          X is REAL array, dimension (LDX,NRHS)
The computed solution vectors X.```

LDX

```          LDX is INTEGER
The leading dimension of the array X.  LDX >= max(1,N).```

B

```          B is REAL array, dimension (LDB,NRHS)
On entry, the right hand side vectors for the system of
linear equations.
On exit, B is overwritten with the difference B - op(A)*X.```

LDB

```          LDB is INTEGER
The leading dimension of the array B.  LDB >= max(1,N).```

RESID

```          RESID is REAL
norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS)```
Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 123 of file sgtt02.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page sgtt02(3) is an alias of sgtt02.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK