Overview | Package | Class | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

## org.netlib.lapack
Class Spoequ

    java.lang.Object
      org.netlib.lapack.Spoequ

    public class Spoequ

extends java.lang.Object

    Following is the description from the original
    Fortran source.  For each array argument, the Java
    version will include an integer offset parameter, so
    the arguments may not match the description exactly.
    Contact seymour@cs.utk.edu with any questions.

     *     ..
     *
     *  Purpose
     *  =======
     *
     *  SPOEQU computes row and column scalings intended to equilibrate a
     *  symmetric positive definite 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
     *  =========
     *
     *  N       (input) INTEGER
     *          The order of the matrix A.  N >= 0.
     *
     *  A       (input) REAL array, dimension (LDA,N)
     *          The N-by-N symmetric positive definite matrix whose scaling
     *          factors are to be computed.  Only the diagonal elements of A

     *          are referenced.
     *
     *  LDA     (input) INTEGER
     *          The leading dimension of the array A.  LDA >= max(1,N).
     *
     *  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
`Spoequ()`

Method Summary
`static void` | `spoequ(int n, float[] a, int _a_offset, int lda, float[] s, int _s_offset, 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

### Spoequ

    public Spoequ()

Method Detail

### spoequ

    public static void spoequ(int n,
                              float[] a,
                              int _a_offset,
                              int lda,
                              float[] s,
                              int _s_offset,
                              floatW scond,
                              floatW amax,
                              intW info)

Overview | Package | Class | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD