org.netlib.lapack
Class SPBEQU

java.lang.Object
  extended by org.netlib.lapack.SPBEQU

public class SPBEQU
extends java.lang.Object

SPBEQU is a simplified interface to the JLAPACK routine spbequ.
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 * ======= * * SPBEQU computes row and column scalings intended to equilibrate a * symmetric positive definite band matrix A and reduce its condition * number (with respect to the two-norm). S contains the scale factors, * S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with * elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This * choice of S puts the condition number of B within a factor N of the * smallest possible condition number over all possible diagonal * scalings. * * Arguments * ========= * * UPLO (input) CHARACTER*1 * = 'U': Upper triangular of A is stored; * = 'L': Lower triangular of A is stored. * * N (input) INTEGER * The order of the matrix A. N >= 0. * * KD (input) INTEGER * The number of superdiagonals of the matrix A if UPLO = 'U', * or the number of subdiagonals if UPLO = 'L'. KD >= 0. * * AB (input) REAL array, dimension (LDAB,N) * The upper or lower triangle of the symmetric band matrix A, * stored in the first KD+1 rows of the array. The j-th column * of A is stored in the j-th column of the array AB as follows: * if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j; * if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd). * * LDAB (input) INTEGER * The leading dimension of the array A. LDAB >= KD+1. * * S (output) REAL array, dimension (N) * If INFO = 0, S contains the scale factors for A. * * SCOND (output) REAL * If INFO = 0, S contains the ratio of the smallest S(i) to * the largest S(i). If SCOND >= 0.1 and AMAX is neither too * large nor too small, it is not worth scaling by S. * * AMAX (output) REAL * 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 i-th argument had an illegal value. * > 0: if INFO = i, the i-th diagonal element is nonpositive. * * ===================================================================== * * .. Parameters ..


Constructor Summary
SPBEQU()
           
 
Method Summary
static void SPBEQU(java.lang.String uplo, int n, int kd, float[][] ab, float[] s, floatW scond, floatW amax, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SPBEQU

public SPBEQU()
Method Detail

SPBEQU

public static void SPBEQU(java.lang.String uplo,
                          int n,
                          int kd,
                          float[][] ab,
                          float[] s,
                          floatW scond,
                          floatW amax,
                          intW info)