---
name: "sget39.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/sget39.f"
---

# sget39.f(3)

## NAME

TESTING/EIG/sget39.f

## SYNOPSIS

### Functions/Subroutines

subroutine **sget39** (rmax, lmax, ninfo, knt)\
 **SGET39**

## Function/Subroutine Documentation

### subroutine sget39 (real rmax, integer lmax, integer ninfo, integer knt)

**SGET39**

**Purpose:**

```
!>
!> SGET39 tests SLAQTR, a routine for solving the real or
!> special complex quasi upper triangular system
!>
!>      op(T)*p = scale*c,
!> or
!>      op(T + iB)*(p+iq) = scale*(c+id),
!>
!> in real arithmetic. T is upper quasi-triangular.
!> If it is complex, then the first diagonal block of T must be
!> 1 by 1, B has the special structure
!>
!>                B = [ b(1) b(2) ... b(n) ]
!>                    [       w            ]
!>                    [           w        ]
!>                    [              .     ]
!>                    [                 w  ]
!>
!> op(A) = A or A', where A' denotes the conjugate transpose of
!> the matrix A.
!>
!> On input, X = [ c ].  On output, X = [ p ].
!>               [ d ]                  [ q ]
!>
!> Scale is an output less than or equal to 1, chosen to avoid
!> overflow in X.
!> This subroutine is specially designed for the condition number
!> estimation in the eigenproblem routine STRSNA.
!>
!> The test code verifies that the following residual is order 1:
!>
!>      ||(T+i*B)*(x1+i*x2) - scale*(d1+i*d2)||
!>    -----------------------------------------
!>        max(ulp*(||T||+||B||)*(||x1||+||x2||),
!>            (||T||+||B||)*smlnum/ulp,
!>            smlnum)
!>
!> (The (||T||+||B||)*smlnum/ulp term accounts for possible
!>  (gradual or nongradual) underflow in x1 and x2.)
!>
```

**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
!>          Number of examples where INFO is nonzero.
!>
```

*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 **102** of file **sget39.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.