org.netlib.lapack
Class Spbtf2

java.lang.Object
  org.netlib.lapack.Spbtf2

public class Spbtf2
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
 *  =======
 *
 *  SPBTF2 computes the Cholesky factorization of a real symmetric
 *  positive definite band matrix A.
 *
 *  The factorization has the form
 *     A = U' * U ,  if UPLO = 'U', or
 *     A = L  * L',  if UPLO = 'L',
 *  where U is an upper triangular matrix, U' is the transpose of U, and

 *  L is lower triangular.
 *
 *  This is the unblocked version of the algorithm, calling Level 2 BLAS.
 *
 *  Arguments
 *  =========
 *
 *  UPLO    (input) CHARACTER*1
 *          Specifies whether the upper or lower triangular part of the
 *          symmetric matrix A is stored:
 *          = 'U':  Upper triangular
 *          = 'L':  Lower triangular
 *
 *  N       (input) INTEGER
 *          The order of the matrix A.  N >= 0.
 *
 *  KD      (input) INTEGER
 *          The number of super-diagonals of the matrix A if UPLO = 'U',

 *          or the number of sub-diagonals if UPLO = 'L'.  KD >= 0.
 *
 *  AB      (input/output) REAL array, dimension (LDAB,N)
 *          On entry, 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).
 *
 *          On exit, if INFO = 0, the triangular factor U or L from the
 *          Cholesky factorization A = U'*U or A = L*L' of the band
 *          matrix A, in the same storage format as A.
 *
 *  LDAB    (input) INTEGER
 *          The leading dimension of the array AB.  LDAB >= KD+1.
 *
 *  INFO    (output) INTEGER
 *          = 0: successful exit
 *          < 0: if INFO = -k, the k-th argument had an illegal value
 *          > 0: if INFO = k, the leading minor of order k is not
 *               positive definite, and the factorization could not be
 *               completed.
 *
 *  Further Details
 *  ===============
 *
 *  The band storage scheme is illustrated by the following example, when
 *  N = 6, KD = 2, and UPLO = 'U':
 *
 *  On entry:                       On exit:
 *
 *      *    *   a13  a24  a35  a46      *    *   u13  u24  u35  u46
 *      *   a12  a23  a34  a45  a56      *   u12  u23  u34  u45  u56
 *     a11  a22  a33  a44  a55  a66     u11  u22  u33  u44  u55  u66
 *
 *  Similarly, if UPLO = 'L' the format of A is as follows:
 *
 *  On entry:                       On exit:
 *
 *     a11  a22  a33  a44  a55  a66     l11  l22  l33  l44  l55  l66
 *     a21  a32  a43  a54  a65   *      l21  l32  l43  l54  l65   *
 *     a31  a42  a53  a64   *    *      l31  l42  l53  l64   *    *
 *
 *  Array elements marked * are not used by the routine.
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

Spbtf2()

Method Summary

static void

spbtf2(java.lang.String uplo, int n, int kd, float[] ab, int _ab_offset, int ldab, intW info)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Spbtf2

public Spbtf2()

Method Detail

spbtf2

public static void spbtf2(java.lang.String uplo,
                          int n,
                          int kd,
                          float[] ab,
                          int _ab_offset,
                          int ldab,
                          intW info)