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Class org.netlib.lapack.Dsteqr

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

public class Dsteqr

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
 *  =======
 *
 *  DSTEQR computes all eigenvalues and, optionally, eigenvectors of a
 *  symmetric tridiagonal matrix using the implicit QL or QR method.
 *  The eigenvectors of a full or band symmetric matrix can also be found
 *  if DSYTRD or DSPTRD or DSBTRD has been used to reduce this matrix to
 *  tridiagonal form.
 *
 *  Arguments
 *  =========
 *
 *  COMPZ   (input) CHARACTER*1
 *          = 'N':  Compute eigenvalues only.
 *          = 'V':  Compute eigenvalues and eigenvectors of the original
 *                  symmetric matrix.  On entry, Z must contain the
 *                  orthogonal matrix used to reduce the original matrix
 *                  to tridiagonal form.
 *          = 'I':  Compute eigenvalues and eigenvectors of the
 *                  tridiagonal matrix.  Z is initialized to the identity
 *                  matrix.
 *
 *  N       (input) INTEGER
 *          The order of the matrix.  N >= 0.
 *
 *  D       (input/output) DOUBLE PRECISION array, dimension (N)
 *          On entry, the diagonal elements of the tridiagonal matrix.
 *          On exit, if INFO = 0, the eigenvalues in ascending order.
 *
 *  E       (input/output) DOUBLE PRECISION array, dimension (N-1)
 *          On entry, the (n-1) subdiagonal elements of the tridiagonal
 *          matrix.
 *          On exit, E has been destroyed.
 *
 *  Z       (input/output) DOUBLE PRECISION array, dimension (LDZ, N)
 *          On entry, if  COMPZ = 'V', then Z contains the orthogonal
 *          matrix used in the reduction to tridiagonal form.
 *          On exit, if INFO = 0, then if  COMPZ = 'V', Z contains the
 *          orthonormal eigenvectors of the original symmetric matrix,
 *          and if COMPZ = 'I', Z contains the orthonormal eigenvectors
 *          of the symmetric tridiagonal matrix.
 *          If COMPZ = 'N', then Z is not referenced.
 *
 *  LDZ     (input) INTEGER
 *          The leading dimension of the array Z.  LDZ >= 1, and if
 *          eigenvectors are desired, then  LDZ >= max(1,N).
 *
 *  WORK    (workspace) DOUBLE PRECISION array, dimension (max(1,2*N-2))
 *          If COMPZ = 'N', then WORK is not referenced.
 *
 *  INFO    (output) INTEGER
 *          = 0:  successful exit
 *          < 0:  if INFO = -i, the i-th argument had an illegal value
 *          > 0:  the algorithm has failed to find all the eigenvalues in
 *                a total of 30*N iterations; if INFO = i, then i
 *                elements of E have not converged to zero; on exit, D
 *                and E contain the elements of a symmetric tridiagonal
 *                matrix which is orthogonally similar to the original
 *                matrix.
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Dsteqr()

dsteqr(String, int, double[], int, double[], int, double[], int, int, double[], int, intW)

 public Dsteqr()

 public static void dsteqr(String compz,
                           int n,
                           double d[],
                           int _d_offset,
                           double e[],
                           int _e_offset,
                           double z[],
                           int _z_offset,
                           int ldz,
                           double work[],
                           int _work_offset,
                           intW info)

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