org.netlib.lapack
Class SLACN2
java.lang.Object
org.netlib.lapack.SLACN2
public class SLACN2
- extends java.lang.Object
SLACN2 is a simplified interface to the JLAPACK routine slacn2.
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
* =======
*
* SLACN2 estimates the 1-norm of a square, real matrix A.
* Reverse communication is used for evaluating matrix-vector products.
*
* Arguments
* =========
*
* N (input) INTEGER
* The order of the matrix. N >= 1.
*
* V (workspace) REAL array, dimension (N)
* On the final return, V = A*W, where EST = norm(V)/norm(W)
* (W is not returned).
*
* X (input/output) REAL array, dimension (N)
* On an intermediate return, X should be overwritten by
* A * X, if KASE=1,
* A' * X, if KASE=2,
* and SLACN2 must be re-called with all the other parameters
* unchanged.
*
* ISGN (workspace) INTEGER array, dimension (N)
*
* EST (input/output) REAL
* On entry with KASE = 1 or 2 and ISAVE(1) = 3, EST should be
* unchanged from the previous call to SLACN2.
* On exit, EST is an estimate (a lower bound) for norm(A).
*
* KASE (input/output) INTEGER
* On the initial call to SLACN2, KASE should be 0.
* On an intermediate return, KASE will be 1 or 2, indicating
* whether X should be overwritten by A * X or A' * X.
* On the final return from SLACN2, KASE will again be 0.
*
* ISAVE (input/output) INTEGER array, dimension (3)
* ISAVE is used to save variables between calls to SLACN2
*
* Further Details
* ======= =======
*
* Contributed by Nick Higham, University of Manchester.
* Originally named SONEST, dated March 16, 1988.
*
* Reference: N.J. Higham, "FORTRAN codes for estimating the one-norm of
* a real or complex matrix, with applications to condition estimation",
* ACM Trans. Math. Soft., vol. 14, no. 4, pp. 381-396, December 1988.
*
* This is a thread safe version of SLACON, which uses the array ISAVE
* in place of a SAVE statement, as follows:
*
* SLACON SLACN2
* JUMP ISAVE(1)
* J ISAVE(2)
* ITER ISAVE(3)
*
* =====================================================================
*
* .. Parameters ..
Method Summary |
static void |
SLACN2(int n,
float[] v,
float[] x,
int[] isgn,
floatW est,
intW kase,
int[] isave)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
SLACN2
public SLACN2()
SLACN2
public static void SLACN2(int n,
float[] v,
float[] x,
int[] isgn,
floatW est,
intW kase,
int[] isave)