# slas2.f man page

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 (realF, realG, realH, realSSMIN, realSSMAX)

**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.

**Date:**September 2012

**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. (On machines with partial overflow, like the Cray, overflow may occur if the largest singular value is within a factor of 2 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 108 of file slas2.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

slas2(3) is an alias of slas2.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK