org.netlib.lapack
Class DGBEQU
java.lang.Object
org.netlib.lapack.DGBEQU
public class DGBEQU
 extends java.lang.Object
DGBEQU is a simplified interface to the JLAPACK routine dgbequ.
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
* =======
*
* DGBEQU computes row and column scalings intended to equilibrate an
* MbyN band matrix A and reduce its condition number. R returns the
* row scale factors and C the column scale factors, chosen to try to
* make the largest element in each row and column of the matrix B with
* elements B(i,j)=R(i)*A(i,j)*C(j) have absolute value 1.
*
* R(i) and C(j) are restricted to be between SMLNUM = smallest safe
* number and BIGNUM = largest safe number. Use of these scaling
* factors is not guaranteed to reduce the condition number of A but
* works well in practice.
*
* 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.
*
* KL (input) INTEGER
* The number of subdiagonals within the band of A. KL >= 0.
*
* KU (input) INTEGER
* The number of superdiagonals within the band of A. KU >= 0.
*
* AB (input) DOUBLE PRECISION array, dimension (LDAB,N)
* The band matrix A, stored in rows 1 to KL+KU+1. The jth
* column of A is stored in the jth column of the array AB as
* follows:
* AB(ku+1+ij,j) = A(i,j) for max(1,jku)<=i<=min(m,j+kl).
*
* LDAB (input) INTEGER
* The leading dimension of the array AB. LDAB >= KL+KU+1.
*
* R (output) DOUBLE PRECISION array, dimension (M)
* If INFO = 0, or INFO > M, R contains the row scale factors
* for A.
*
* C (output) DOUBLE PRECISION array, dimension (N)
* If INFO = 0, C contains the column scale factors for A.
*
* ROWCND (output) DOUBLE PRECISION
* If INFO = 0 or INFO > M, ROWCND contains the ratio of the
* smallest R(i) to the largest R(i). If ROWCND >= 0.1 and
* AMAX is neither too large nor too small, it is not worth
* scaling by R.
*
* COLCND (output) DOUBLE PRECISION
* If INFO = 0, COLCND contains the ratio of the smallest
* C(i) to the largest C(i). If COLCND >= 0.1, it is not
* worth scaling by C.
*
* AMAX (output) DOUBLE PRECISION
* Absolute value of largest matrix element. If AMAX is very
* close to overflow or very close to underflow, the matrix
* should be scaled.
*
* INFO (output) INTEGER
* = 0: successful exit
* < 0: if INFO = i, the ith argument had an illegal value
* > 0: if INFO = i, and i is
* <= M: the ith row of A is exactly zero
* > M: the (iM)th column of A is exactly zero
*
* =====================================================================
*
* .. Parameters ..
Method Summary 
static void 
DGBEQU(int m,
int n,
int kl,
int ku,
double[][] ab,
double[] r,
double[] c,
doubleW rowcnd,
doubleW colcnd,
doubleW amax,
intW info)

Methods inherited from class java.lang.Object 
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait 
DGBEQU
public DGBEQU()
DGBEQU
public static void DGBEQU(int m,
int n,
int kl,
int ku,
double[][] ab,
double[] r,
double[] c,
doubleW rowcnd,
doubleW colcnd,
doubleW amax,
intW info)