org.netlib.lapack
Class Dpbequ

java.lang.Object
  org.netlib.lapack.Dpbequ

public class Dpbequ
extends java.lang.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
 *  =======
 *
 *  DPBEQU computes row and column scalings intended to equilibrate a
 *  symmetric positive definite band matrix A and reduce its condition
 *  number (with respect to the two-norm).  S contains the scale factors,
 *  S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with
 *  elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal.  This
 *  choice of S puts the condition number of B within a factor N of the
 *  smallest possible condition number over all possible diagonal
 *  scalings.
 *
 *  Arguments
 *  =========
 *
 *  UPLO    (input) CHARACTER*1
 *          = 'U':  Upper triangular of A is stored;
 *          = 'L':  Lower triangular of A is stored.
 *
 *  N       (input) INTEGER
 *          The order of the matrix A.  N >= 0.
 *
 *  KD      (input) INTEGER
 *          The number of superdiagonals of the matrix A if UPLO = 'U',
 *          or the number of subdiagonals if UPLO = 'L'.  KD >= 0.
 *
 *  AB      (input) DOUBLE PRECISION array, dimension (LDAB,N)
 *          The upper or lower triangle of the symmetric band matrix A,
 *          stored in the first KD+1 rows of the array.  The j-th column

 *          of A is stored in the j-th column of the array AB as follows:
 *          if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j;
 *          if UPLO = 'L', AB(1+i-j,j)    = A(i,j) for j<=i<=min(n,j+kd).
 *
 *  LDAB     (input) INTEGER
 *          The leading dimension of the array A.  LDAB >= KD+1.
 *
 *  S       (output) DOUBLE PRECISION array, dimension (N)
 *          If INFO = 0, S contains the scale factors for A.
 *
 *  SCOND   (output) DOUBLE PRECISION
 *          If INFO = 0, S contains the ratio of the smallest S(i) to
 *          the largest S(i).  If SCOND >= 0.1 and AMAX is neither too
 *          large nor too small, it is not worth scaling by S.
 *
 *  AMAX    (output) DOUBLE PRECISION
 *          Absolute value of largest matrix element.  If AMAX is very
 *          close to overflow or very close to underflow, the matrix
 *          should be scaled.
 *
 *  INFO    (output) INTEGER
 *          = 0:  successful exit
 *          < 0:  if INFO = -i, the i-th argument had an illegal value.
 *          > 0:  if INFO = i, the i-th diagonal element is nonpositive.

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

Constructor Summary

Dpbequ()

Method Summary

static void

dpbequ(java.lang.String uplo, int n, int kd, double[] ab, int _ab_offset, int ldab, double[] s, int _s_offset, doubleW scond, doubleW amax, intW info)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Dpbequ

public Dpbequ()

Method Detail

dpbequ

public static void dpbequ(java.lang.String uplo,
                          int n,
                          int kd,
                          double[] ab,
                          int _ab_offset,
                          int ldab,
                          double[] s,
                          int _s_offset,
                          doubleW scond,
                          doubleW amax,
                          intW info)