All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class org.netlib.lapack.Dlas2

java.lang.Object
   |
   +----org.netlib.lapack.Dlas2

public class Dlas2

extends Object

Following is the description from the original
Fortran source.  For each array argument, the Java
version will include an integer offset parameter, so
the arguments may not match the description exactly.
Contact seymour@cs.utk.edu with any questions.

 *     ..
 *
 *  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.
 *
 *  ====================================================================
 *
 *     .. Parameters ..

Dlas2()

dlas2(double, double, double, doubleW, doubleW)

 public Dlas2()

 public static void dlas2(double f,
                          double g,
                          double h,
                          doubleW ssmin,
                          doubleW ssmax)

All Packages  Class Hierarchy  This Package  Previous  Next  Index