Provided by: liblapack-doc-man_3.5.0-2ubuntu1_all
NAME
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.