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## org.netlib.lapack
Class SSPGVD

    java.lang.Object
      org.netlib.lapack.SSPGVD

    public class SSPGVD

extends java.lang.Object

    SSPGVD is a simplified interface to the JLAPACK routine sspgvd.
    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
     *  =======
     *
     *  SSPGVD computes all the eigenvalues, and optionally, the eigenvectors
     *  of a real generalized symmetric-definite eigenproblem, of the form
     *  A*x=(lambda)*B*x,  A*Bx=(lambda)*x,  or B*A*x=(lambda)*x.  Here A and
     *  B are assumed to be symmetric, stored in packed format, and B is also
     *  positive definite.
     *  If eigenvectors are desired, it uses a divide and conquer algorithm.

     *
     *  The divide and conquer algorithm makes very mild assumptions about
     *  floating point arithmetic. It will work on machines with a guard
     *  digit in add/subtract, or on those binary machines without guard
     *  digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or
     *  Cray-2. It could conceivably fail on hexadecimal or decimal machines

     *  without guard digits, but we know of none.
     *
     *  Arguments
     *  =========
     *
     *  ITYPE   (input) INTEGER
     *          Specifies the problem type to be solved:
     *          = 1:  A*x = (lambda)*B*x
     *          = 2:  A*B*x = (lambda)*x
     *          = 3:  B*A*x = (lambda)*x
     *
     *  JOBZ    (input) CHARACTER*1
     *          = 'N':  Compute eigenvalues only;
     *          = 'V':  Compute eigenvalues and eigenvectors.
     *
     *  UPLO    (input) CHARACTER*1
     *          = 'U':  Upper triangles of A and B are stored;
     *          = 'L':  Lower triangles of A and B are stored.
     *
     *  N       (input) INTEGER
     *          The order of the matrices A and B.  N >= 0.
     *
     *  AP      (input/output) REAL array, dimension (N*(N+1)/2)
     *          On entry, the upper or lower triangle of the symmetric matrix
     *          A, packed columnwise in a linear array.  The j-th column of A
     *          is stored in the array AP as follows:
     *          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
     *          if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.

     *
     *          On exit, the contents of AP are destroyed.
     *
     *  BP      (input/output) REAL array, dimension (N*(N+1)/2)
     *          On entry, the upper or lower triangle of the symmetric matrix
     *          B, packed columnwise in a linear array.  The j-th column of B
     *          is stored in the array BP as follows:
     *          if UPLO = 'U', BP(i + (j-1)*j/2) = B(i,j) for 1<=i<=j;
     *          if UPLO = 'L', BP(i + (j-1)*(2*n-j)/2) = B(i,j) for j<=i<=n.

     *
     *          On exit, the triangular factor U or L from the Cholesky
     *          factorization B = U**T*U or B = L*L**T, in the same storage
     *          format as B.
     *
     *  W       (output) REAL array, dimension (N)
     *          If INFO = 0, the eigenvalues in ascending order.
     *
     *  Z       (output) REAL array, dimension (LDZ, N)
     *          If JOBZ = 'V', then if INFO = 0, Z contains the matrix Z of
     *          eigenvectors.  The eigenvectors are normalized as follows:
     *          if ITYPE = 1 or 2, Z**T*B*Z = I;
     *          if ITYPE = 3, Z**T*inv(B)*Z = I.
     *          If JOBZ = 'N', then Z is not referenced.
     *
     *  LDZ     (input) INTEGER
     *          The leading dimension of the array Z.  LDZ >= 1, and if
     *          JOBZ = 'V', LDZ >= max(1,N).
     *
     *  WORK    (workspace/output) REAL array, dimension (MAX(1,LWORK))
     *          On exit, if INFO = 0, WORK(1) returns the required LWORK.
     *
     *  LWORK   (input) INTEGER
     *          The dimension of the array WORK.
     *          If N <= 1,               LWORK >= 1.
     *          If JOBZ = 'N' and N > 1, LWORK >= 2*N.
     *          If JOBZ = 'V' and N > 1, LWORK >= 1 + 6*N + 2*N**2.
     *
     *          If LWORK = -1, then a workspace query is assumed; the routine
     *          only calculates the required sizes of the WORK and IWORK
     *          arrays, returns these values as the first entries of the WORK
     *          and IWORK arrays, and no error message related to LWORK or
     *          LIWORK is issued by XERBLA.
     *
     *  IWORK   (workspace/output) INTEGER array, dimension (MAX(1,LIWORK))
     *          On exit, if INFO = 0, IWORK(1) returns the required LIWORK.
     *
     *  LIWORK  (input) INTEGER
     *          The dimension of the array IWORK.
     *          If JOBZ  = 'N' or N <= 1, LIWORK >= 1.
     *          If JOBZ  = 'V' and N > 1, LIWORK >= 3 + 5*N.
     *
     *          If LIWORK = -1, then a workspace query is assumed; the
     *          routine only calculates the required sizes of the WORK and
     *          IWORK arrays, returns these values as the first entries of
     *          the WORK and IWORK arrays, and no error message related to
     *          LWORK or LIWORK is issued by XERBLA.
     *
     *  INFO    (output) INTEGER
     *          = 0:  successful exit
     *          < 0:  if INFO = -i, the i-th argument had an illegal value
     *          > 0:  SPPTRF or SSPEVD returned an error code:
     *             <= N:  if INFO = i, SSPEVD failed to converge;
     *                    i off-diagonal elements of an intermediate
     *                    tridiagonal form did not converge to zero;
     *             > N:   if INFO = N + i, for 1 <= i <= N, then the leading

     *                    minor of order i of B is not positive definite.
     *                    The factorization of B could not be completed and
     *                    no eigenvalues or eigenvectors were computed.
     *
     *  Further Details
     *  ===============
     *
     *  Based on contributions by
     *     Mark Fahey, Department of Mathematics, Univ. of Kentucky, USA
     *
     *  =====================================================================
     *
     *     .. Parameters ..

Constructor Summary
`SSPGVD()`

Method Summary
`static void` | `SSPGVD(int itype, java.lang.String jobz, java.lang.String uplo, int n, float[] ap, float[] bp, float[] w, float[][] z, float[] work, int lwork, int[] iwork, int liwork, intW info)`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### SSPGVD

    public SSPGVD()

Method Detail

### SSPGVD

    public static void SSPGVD(int itype,
                              java.lang.String jobz,
                              java.lang.String uplo,
                              int n,
                              float[] ap,
                              float[] bp,
                              float[] w,
                              float[][] z,
                              float[] work,
                              int lwork,
                              int[] iwork,
                              int liwork,
                              intW info)

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