org.netlib.lapack
Class DPPEQU
java.lang.Object
org.netlib.lapack.DPPEQU
public class DPPEQU
 extends java.lang.Object
DPPEQU is a simplified interface to the JLAPACK routine dppequ.
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
* =======
*
* DPPEQU computes row and column scalings intended to equilibrate a
* symmetric positive definite matrix A in packed storage and reduce
* its condition number (with respect to the twonorm). 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 triangle of A is stored;
* = 'L': Lower triangle of A is stored.
*
* N (input) INTEGER
* The order of the matrix A. N >= 0.
*
* AP (input) DOUBLE PRECISION array, dimension (N*(N+1)/2)
* The upper or lower triangle of the symmetric matrix A, packed
* columnwise in a linear array. The jth column of A is stored
* in the array AP as follows:
* if UPLO = 'U', AP(i + (j1)*j/2) = A(i,j) for 1<=i<=j;
* if UPLO = 'L', AP(i + (j1)*(2nj)/2) = A(i,j) for j<=i<=n.
*
* S (output) DOUBLE PRECISION array, dimension (N)
* If INFO = 0, S contains the scale factors for A.
*
* SCOND (output) DOUBLE PRECISION
* 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) 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, the ith diagonal element is nonpositive.
*
* =====================================================================
*
* .. Parameters ..
Method Summary 
static void 
DPPEQU(java.lang.String uplo,
int n,
double[] ap,
double[] s,
doubleW scond,
doubleW amax,
intW info)

Methods inherited from class java.lang.Object 
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait 
DPPEQU
public DPPEQU()
DPPEQU
public static void DPPEQU(java.lang.String uplo,
int n,
double[] ap,
double[] s,
doubleW scond,
doubleW amax,
intW info)