org.netlib.lapack
Class DLAQPS
java.lang.Object
org.netlib.lapack.DLAQPS
public class DLAQPS
- extends java.lang.Object
DLAQPS is a simplified interface to the JLAPACK routine dlaqps.
This interface converts Java-style 2D row-major arrays into
the 1D column-major 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
* =======
*
* DLAQPS computes a step of QR factorization with column pivoting
* of a real M-by-N matrix A by using Blas-3. It tries to factorize
* NB columns from A starting from the row OFFSET+1, and updates all
* of the matrix with Blas-3 xGEMM.
*
* In some cases, due to catastrophic cancellations, it cannot
* factorize NB columns. Hence, the actual number of factorized
* columns is returned in KB.
*
* Block A(1:OFFSET,1:N) is accordingly pivoted, but not factorized.
*
* Arguments
* =========
*
* M (input) INTEGER
* The number of rows of the matrix A. M >= 0.
*
* N (input) INTEGER
* The number of columns of the matrix A. N >= 0
*
* OFFSET (input) INTEGER
* The number of rows of A that have been factorized in
* previous steps.
*
* NB (input) INTEGER
* The number of columns to factorize.
*
* KB (output) INTEGER
* The number of columns actually factorized.
*
* A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
* On entry, the M-by-N matrix A.
* On exit, block A(OFFSET+1:M,1:KB) is the triangular
* factor obtained and block A(1:OFFSET,1:N) has been
* accordingly pivoted, but no factorized.
* The rest of the matrix, block A(OFFSET+1:M,KB+1:N) has
* been updated.
*
* LDA (input) INTEGER
* The leading dimension of the array A. LDA >= max(1,M).
*
* JPVT (input/output) INTEGER array, dimension (N)
* JPVT(I) = K <==> Column K of the full matrix A has been
* permuted into position I in AP.
*
* TAU (output) DOUBLE PRECISION array, dimension (KB)
* The scalar factors of the elementary reflectors.
*
* VN1 (input/output) DOUBLE PRECISION array, dimension (N)
* The vector with the partial column norms.
*
* VN2 (input/output) DOUBLE PRECISION array, dimension (N)
* The vector with the exact column norms.
*
* AUXV (input/output) DOUBLE PRECISION array, dimension (NB)
* Auxiliar vector.
*
* F (input/output) DOUBLE PRECISION array, dimension (LDF,NB)
* Matrix F' = L*Y'*A.
*
* LDF (input) INTEGER
* The leading dimension of the array F. LDF >= max(1,N).
*
* Further Details
* ===============
*
* Based on contributions by
* G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain
* X. Sun, Computer Science Dept., Duke University, USA
*
* Partial column norm updating strategy modified by
* Z. Drmac and Z. Bujanovic, Dept. of Mathematics,
* University of Zagreb, Croatia.
* June 2006.
* For more details see LAPACK Working Note 176.
* =====================================================================
*
* .. Parameters ..
Method Summary |
static void |
DLAQPS(int m,
int n,
int offset,
int nb,
intW kb,
double[][] a,
int[] jpvt,
double[] tau,
double[] vn1,
double[] vn2,
double[] auxv,
double[][] f)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
DLAQPS
public DLAQPS()
DLAQPS
public static void DLAQPS(int m,
int n,
int offset,
int nb,
intW kb,
double[][] a,
int[] jpvt,
double[] tau,
double[] vn1,
double[] vn2,
double[] auxv,
double[][] f)