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RedHat 9 (Linux i386) - man page for dlas2 (redhat section l)

DLAS2(l)					)					 DLAS2(l)

NAME
       DLAS2 - compute the singular values of the 2-by-2 matrix [ F G ] [ 0 H ]

SYNOPSIS
       SUBROUTINE DLAS2( F, G, H, SSMIN, SSMAX )

	   DOUBLE	 PRECISION F, G, H, SSMAX, SSMIN

PURPOSE
       DLAS2  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.

ARGUMENTS
       F       (input) DOUBLE PRECISION
	       The (1,1) element of the 2-by-2 matrix.

       G       (input) DOUBLE PRECISION
	       The (1,2) element of the 2-by-2 matrix.

       H       (input) DOUBLE PRECISION
	       The (2,2) element of the 2-by-2 matrix.

       SSMIN   (output) DOUBLE PRECISION
	       The smaller singular value.

       SSMAX   (output) DOUBLE PRECISION
	       The larger singular value.

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.

LAPACK version 3.0			   15 June 2000 				 DLAS2(l)


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