org.netlib.lapack
Class Dsbgv

java.lang.Object
  org.netlib.lapack.Dsbgv

public class Dsbgv
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
 *  =======
 *
 *  DSBGV computes all the eigenvalues, and optionally, the eigenvectors

 *  of a real generalized symmetric-definite banded eigenproblem, of
 *  the form A*x=(lambda)*B*x. Here A and B are assumed to be symmetric
 *  and banded, and B is also positive definite.
 *
 *  Arguments
 *  =========
 *
 *  JOBZ    (input) CHARACTER*1
 *          = 'N':  Compute eigenvalues only;
 *          = 'V':  Compute eigenvalues and eigenvectors.
 *
 *  UPLO    (input) CHARACTER*1
 *          = 'U':  Upper triangles of A and B are stored;
 *          = 'L':  Lower triangles of A and B are stored.
 *
 *  N       (input) INTEGER
 *          The order of the matrices A and B.  N >= 0.
 *
 *  KA      (input) INTEGER
 *          The number of superdiagonals of the matrix A if UPLO = 'U',
 *          or the number of subdiagonals if UPLO = 'L'. KA >= 0.
 *
 *  KB      (input) INTEGER
 *          The number of superdiagonals of the matrix B if UPLO = 'U',
 *          or the number of subdiagonals if UPLO = 'L'. KB >= 0.
 *
 *  AB      (input/output) DOUBLE PRECISION array, dimension (LDAB, N)
 *          On entry, the upper or lower triangle of the symmetric band
 *          matrix A, stored in the first ka+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(ka+1+i-j,j) = A(i,j) for max(1,j-ka)<=i<=j;
 *          if UPLO = 'L', AB(1+i-j,j)    = A(i,j) for j<=i<=min(n,j+ka).
 *
 *          On exit, the contents of AB are destroyed.
 *
 *  LDAB    (input) INTEGER
 *          The leading dimension of the array AB.  LDAB >= KA+1.
 *
 *  BB      (input/output) DOUBLE PRECISION array, dimension (LDBB, N)
 *          On entry, the upper or lower triangle of the symmetric band
 *          matrix B, stored in the first kb+1 rows of the array.  The
 *          j-th column of B is stored in the j-th column of the array BB
 *          as follows:
 *          if UPLO = 'U', BB(kb+1+i-j,j) = B(i,j) for max(1,j-kb)<=i<=j;
 *          if UPLO = 'L', BB(1+i-j,j)    = B(i,j) for j<=i<=min(n,j+kb).
 *
 *          On exit, the factor S from the split Cholesky factorization
 *          B = S**T*S, as returned by DPBSTF.
 *
 *  LDBB    (input) INTEGER
 *          The leading dimension of the array BB.  LDBB >= KB+1.
 *
 *  W       (output) DOUBLE PRECISION array, dimension (N)
 *          If INFO = 0, the eigenvalues in ascending order.
 *
 *  Z       (output) DOUBLE PRECISION array, dimension (LDZ, N)
 *          If JOBZ = 'V', then if INFO = 0, Z contains the matrix Z of
 *          eigenvectors, with the i-th column of Z holding the
 *          eigenvector associated with W(i). The eigenvectors are
 *          normalized so that Z**T*B*Z = I.
 *          If JOBZ = 'N', then Z is not referenced.
 *
 *  LDZ     (input) INTEGER
 *          The leading dimension of the array Z.  LDZ >= 1, and if
 *          JOBZ = 'V', LDZ >= N.
 *
 *  WORK    (workspace) DOUBLE PRECISION array, dimension (3*N)
 *
 *  INFO    (output) INTEGER
 *          = 0:  successful exit
 *          < 0:  if INFO = -i, the i-th argument had an illegal value
 *          > 0:  if INFO = i, and i is:
 *             <= N:  the algorithm failed to converge:
 *                    i off-diagonal elements of an intermediate
 *                    tridiagonal form did not converge to zero;
 *             > N:   if INFO = N + i, for 1 <= i <= N, then DPBSTF
 *                    returned INFO = i: B is not positive definite.
 *                    The factorization of B could not be completed and
 *                    no eigenvalues or eigenvectors were computed.
 *
 *  =====================================================================
 *
 *     .. Local Scalars ..

Constructor Summary

Dsbgv()

Method Summary

static void

dsbgv(java.lang.String jobz, java.lang.String uplo, int n, int ka, int kb, double[] ab, int _ab_offset, int ldab, double[] bb, int _bb_offset, int ldbb, double[] w, int _w_offset, double[] z, int _z_offset, int ldz, double[] work, int _work_offset, intW info)

Methods inherited from class java.lang.Object

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

Constructor Detail

Dsbgv

public Dsbgv()

Method Detail

dsbgv

public static void dsbgv(java.lang.String jobz,
                         java.lang.String uplo,
                         int n,
                         int ka,
                         int kb,
                         double[] ab,
                         int _ab_offset,
                         int ldab,
                         double[] bb,
                         int _bb_offset,
                         int ldbb,
                         double[] w,
                         int _w_offset,
                         double[] z,
                         int _z_offset,
                         int ldz,
                         double[] work,
                         int _work_offset,
                         intW info)