# slas2.f - Man Page

SRC/slas2.f

## Synopsis

### Functions/Subroutines

subroutine **slas2** (f, g, h, ssmin, ssmax)**SLAS2** computes singular values of a 2-by-2 triangular matrix.

## Function/Subroutine Documentation

### subroutine slas2 (real f, real g, real h, real ssmin, real ssmax)

**SLAS2** computes singular values of a 2-by-2 triangular matrix.

**Purpose:**

SLAS2 computes the singular values of the 2-by-2 matrix [ F G ] [ 0 H ]. On return, SSMIN is the smaller singular value and SSMAX is the larger singular value.

**Parameters***F*F is REAL The (1,1) element of the 2-by-2 matrix.

*G*G is REAL The (1,2) element of the 2-by-2 matrix.

*H*H is REAL The (2,2) element of the 2-by-2 matrix.

*SSMIN*SSMIN is REAL The smaller singular value.

*SSMAX*SSMAX is REAL The larger singular value.

**Author**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Further Details:**

Barring over/underflow, all output quantities are correct to within a few units in the last place (ulps), even in the absence of a guard digit in addition/subtraction. In IEEE arithmetic, the code works correctly if one matrix element is infinite. Overflow will not occur unless the largest singular value itself overflows, or is within a few ulps of overflow. Underflow is harmless if underflow is gradual. Otherwise, results may correspond to a matrix modified by perturbations of size near the underflow threshold.

Definition at line **104** of file **slas2.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page slas2(3) is an alias of slas2.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK