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Class org.netlib.lapack.Dlaic1

java.lang.Object
   |
   +----org.netlib.lapack.Dlaic1

public class Dlaic1

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
 *  =======
 *
 *  DLAIC1 applies one step of incremental condition estimation in
 *  its simplest version:
 *
 *  Let x, twonorm(x) = 1, be an approximate singular vector of an j-by-j
 *  lower triangular matrix L, such that
 *           twonorm(L*x) = sest
 *  Then DLAIC1 computes sestpr, s, c such that
 *  the vector
 *                  [ s*x ]
 *           xhat = [  c  ]
 *  is an approximate singular vector of
 *                  [ L     0  ]
 *           Lhat = [ w' gamma ]
 *  in the sense that
 *           twonorm(Lhat*xhat) = sestpr.
 *
 *  Depending on JOB, an estimate for the largest or smallest singular
 *  value is computed.
 *
 *  Note that [s c]' and sestpr**2 is an eigenpair of the system
 *
 *      diag(sest*sest, 0) + [alpha  gamma] * [ alpha ]
 *                                            [ gamma ]
 *
 *  where  alpha =  x'*w.
 *
 *  Arguments
 *  =========
 *
 *  JOB     (input) INTEGER
 *          = 1: an estimate for the largest singular value is computed.
 *          = 2: an estimate for the smallest singular value is computed.
 *
 *  J       (input) INTEGER
 *          Length of X and W
 *
 *  X       (input) DOUBLE PRECISION array, dimension (J)
 *          The j-vector x.
 *
 *  SEST    (input) DOUBLE PRECISION
 *          Estimated singular value of j by j matrix L
 *
 *  W       (input) DOUBLE PRECISION array, dimension (J)
 *          The j-vector w.
 *
 *  GAMMA   (input) DOUBLE PRECISION
 *          The diagonal element gamma.
 *
 *  SEDTPR  (output) DOUBLE PRECISION
 *          Estimated singular value of (j+1) by (j+1) matrix Lhat.
 *
 *  S       (output) DOUBLE PRECISION
 *          Sine needed in forming xhat.
 *
 *  C       (output) DOUBLE PRECISION
 *          Cosine needed in forming xhat.
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Dlaic1()

dlaic1(int, int, double[], int, double, double[], int, double, doubleW, doubleW, doubleW)

 public Dlaic1()

 public static void dlaic1(int job,
                           int j,
                           double x[],
                           int _x_offset,
                           double sest,
                           double w[],
                           int _w_offset,
                           double gamma,
                           doubleW sestpr,
                           doubleW s,
                           doubleW c)

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