---
name: "sget31.f"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/sget31.f"
---

# sget31.f(3)

## NAME

TESTING/EIG/sget31.f

## SYNOPSIS

### Functions/Subroutines

subroutine **sget31** (rmax, lmax, ninfo, knt)\
 **SGET31**

## Function/Subroutine Documentation

### subroutine sget31 (real rmax, integer lmax, integer, dimension( 2 ) ninfo, integer knt)

**SGET31**

**Purpose:**

```
!>
!> SGET31 tests SLALN2, a routine for solving
!>
!>    (ca A - w D)X = sB
!>
!> where A is an NA by NA matrix (NA=1 or 2 only), w is a real (NW=1) or
!> complex (NW=2) constant, ca is a real constant, D is an NA by NA real
!> diagonal matrix, and B is an NA by NW matrix (when NW=2 the second
!> column of B contains the imaginary part of the solution).  The code
!> returns X and s, where s is a scale factor, less than or equal to 1,
!> which is chosen to avoid overflow in X.
!>
!> If any singular values of ca A-w D are less than another input
!> parameter SMIN, they are perturbed up to SMIN.
!>
!> The test condition is that the scaled residual
!>
!>     norm( (ca A-w D)*X - s*B ) /
!>           ( max( ulp*norm(ca A-w D), SMIN )*norm(X) )
!>
!> should be on the order of 1.  Here, ulp is the machine precision.
!> Also, it is verified that SCALE is less than or equal to 1, and that
!> XNORM = infinity-norm(X).
!>
```

**Parameters**

*RMAX*

```
!>          RMAX is REAL
!>          Value of the largest test ratio.
!>
```

*LMAX*

```
!>          LMAX is INTEGER
!>          Example number where largest test ratio achieved.
!>
```

*NINFO*

```
!>          NINFO is INTEGER array, dimension (2)
!>          NINFO(1) = number of examples with INFO less than 0
!>          NINFO(2) = number of examples with INFO greater than 0
!>
```

*KNT*

```
!>          KNT is INTEGER
!>          Total number of examples tested.
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **90** of file **sget31.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.