CXML
        	    
LAPACK version 3.0
dlas2(3)

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

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

      DOUBLE	    PRECISION F, G, H, SSMAX, SSMIN

DESCRIPTION
  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.