org.netlib.lapack
Class DLAED8
java.lang.Object
org.netlib.lapack.DLAED8
public class DLAED8
 extends java.lang.Object
DLAED8 is a simplified interface to the JLAPACK routine dlaed8.
This interface converts Javastyle 2D rowmajor arrays into
the 1D columnmajor linearized arrays expected by the lower
level JLAPACK routines. Using this interface also allows you
to omit offset and leading dimension arguments. However, because
of these conversions, these routines will be slower than the low
level ones. Following is the description from the original Fortran
source. Contact seymour@cs.utk.edu with any questions.
* ..
*
* Purpose
* =======
*
* DLAED8 merges the two sets of eigenvalues together into a single
* sorted set. Then it tries to deflate the size of the problem.
* There are two ways in which deflation can occur: when two or more
* eigenvalues are close together or if there is a tiny element in the
* Z vector. For each such occurrence the order of the related secular
* equation problem is reduced by one.
*
* Arguments
* =========
*
* ICOMPQ (input) INTEGER
* = 0: Compute eigenvalues only.
* = 1: Compute eigenvectors of original dense symmetric matrix
* also. On entry, Q contains the orthogonal matrix used
* to reduce the original matrix to tridiagonal form.
*
* K (output) INTEGER
* The number of nondeflated eigenvalues, and the order of the
* related secular equation.
*
* N (input) INTEGER
* The dimension of the symmetric tridiagonal matrix. N >= 0.
*
* QSIZ (input) INTEGER
* The dimension of the orthogonal matrix used to reduce
* the full matrix to tridiagonal form. QSIZ >= N if ICOMPQ = 1.
*
* D (input/output) DOUBLE PRECISION array, dimension (N)
* On entry, the eigenvalues of the two submatrices to be
* combined. On exit, the trailing (NK) updated eigenvalues
* (those which were deflated) sorted into increasing order.
*
* Q (input/output) DOUBLE PRECISION array, dimension (LDQ,N)
* If ICOMPQ = 0, Q is not referenced. Otherwise,
* on entry, Q contains the eigenvectors of the partially solved
* system which has been previously updated in matrix
* multiplies with other partially solved eigensystems.
* On exit, Q contains the trailing (NK) updated eigenvectors
* (those which were deflated) in its last NK columns.
*
* LDQ (input) INTEGER
* The leading dimension of the array Q. LDQ >= max(1,N).
*
* INDXQ (input) INTEGER array, dimension (N)
* The permutation which separately sorts the two subproblems
* in D into ascending order. Note that elements in the second
* half of this permutation must first have CUTPNT added to
* their values in order to be accurate.
*
* RHO (input/output) DOUBLE PRECISION
* On entry, the offdiagonal element associated with the rank1
* cut which originally split the two submatrices which are now
* being recombined.
* On exit, RHO has been modified to the value required by
* DLAED3.
*
* CUTPNT (input) INTEGER
* The location of the last eigenvalue in the leading
* submatrix. min(1,N) <= CUTPNT <= N.
*
* Z (input) DOUBLE PRECISION array, dimension (N)
* On entry, Z contains the updating vector (the last row of
* the first subeigenvector matrix and the first row of the
* second subeigenvector matrix).
* On exit, the contents of Z are destroyed by the updating
* process.
*
* DLAMDA (output) DOUBLE PRECISION array, dimension (N)
* A copy of the first K eigenvalues which will be used by
* DLAED3 to form the secular equation.
*
* Q2 (output) DOUBLE PRECISION array, dimension (LDQ2,N)
* If ICOMPQ = 0, Q2 is not referenced. Otherwise,
* a copy of the first K eigenvectors which will be used by
* DLAED7 in a matrix multiply (DGEMM) to update the new
* eigenvectors.
*
* LDQ2 (input) INTEGER
* The leading dimension of the array Q2. LDQ2 >= max(1,N).
*
* W (output) DOUBLE PRECISION array, dimension (N)
* The first k values of the final deflationaltered zvector and
* will be passed to DLAED3.
*
* PERM (output) INTEGER array, dimension (N)
* The permutations (from deflation and sorting) to be applied
* to each eigenblock.
*
* GIVPTR (output) INTEGER
* The number of Givens rotations which took place in this
* subproblem.
*
* GIVCOL (output) INTEGER array, dimension (2, N)
* Each pair of numbers indicates a pair of columns to take place
* in a Givens rotation.
*
* GIVNUM (output) DOUBLE PRECISION array, dimension (2, N)
* Each number indicates the S value to be used in the
* corresponding Givens rotation.
*
* INDXP (workspace) INTEGER array, dimension (N)
* The permutation used to place deflated values of D at the end
* of the array. INDXP(1:K) points to the nondeflated Dvalues
* and INDXP(K+1:N) points to the deflated eigenvalues.
*
* INDX (workspace) INTEGER array, dimension (N)
* The permutation used to sort the contents of D into ascending
* order.
*
* INFO (output) INTEGER
* = 0: successful exit.
* < 0: if INFO = i, the ith argument had an illegal value.
*
* Further Details
* ===============
*
* Based on contributions by
* Jeff Rutter, Computer Science Division, University of California
* at Berkeley, USA
*
* =====================================================================
*
* .. Parameters ..
Method Summary 
static void 
DLAED8(int icompq,
intW k,
int n,
int qsiz,
double[] d,
double[][] q,
int[] indxq,
doubleW rho,
int cutpnt,
double[] z,
double[] dlamda,
double[][] q2,
double[] w,
int[] perm,
intW givptr,
int[][] givcol,
double[][] givnum,
int[] indxp,
int[] indx,
intW info)

Methods inherited from class java.lang.Object 
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait 
DLAED8
public DLAED8()
DLAED8
public static void DLAED8(int icompq,
intW k,
int n,
int qsiz,
double[] d,
double[][] q,
int[] indxq,
doubleW rho,
int cutpnt,
double[] z,
double[] dlamda,
double[][] q2,
double[] w,
int[] perm,
intW givptr,
int[][] givcol,
double[][] givnum,
int[] indxp,
int[] indx,
intW info)