org.netlib.lapack
Class Sgeev

java.lang.Object
  org.netlib.lapack.Sgeev

public class Sgeev
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
 *  =======
 *
 *  SGEEV computes for an N-by-N real nonsymmetric matrix A, the
 *  eigenvalues and, optionally, the left and/or right eigenvectors.
 *
 *  The right eigenvector v(j) of A satisfies
 *                   A * v(j) = lambda(j) * v(j)
 *  where lambda(j) is its eigenvalue.
 *  The left eigenvector u(j) of A satisfies
 *                u(j)**H * A = lambda(j) * u(j)**H
 *  where u(j)**H denotes the conjugate transpose of u(j).
 *
 *  The computed eigenvectors are normalized to have Euclidean norm
 *  equal to 1 and largest component real.
 *
 *  Arguments
 *  =========
 *
 *  JOBVL   (input) CHARACTER*1
 *          = 'N': left eigenvectors of A are not computed;
 *          = 'V': left eigenvectors of A are computed.
 *
 *  JOBVR   (input) CHARACTER*1
 *          = 'N': right eigenvectors of A are not computed;
 *          = 'V': right eigenvectors of A are computed.
 *
 *  N       (input) INTEGER
 *          The order of the matrix A. N >= 0.
 *
 *  A       (input/output) REAL array, dimension (LDA,N)
 *          On entry, the N-by-N matrix A.
 *          On exit, A has been overwritten.
 *
 *  LDA     (input) INTEGER
 *          The leading dimension of the array A.  LDA >= max(1,N).
 *
 *  WR      (output) REAL array, dimension (N)
 *  WI      (output) REAL array, dimension (N)
 *          WR and WI contain the real and imaginary parts,
 *          respectively, of the computed eigenvalues.  Complex
 *          conjugate pairs of eigenvalues appear consecutively
 *          with the eigenvalue having the positive imaginary part
 *          first.
 *
 *  VL      (output) REAL array, dimension (LDVL,N)
 *          If JOBVL = 'V', the left eigenvectors u(j) are stored one
 *          after another in the columns of VL, in the same order
 *          as their eigenvalues.
 *          If JOBVL = 'N', VL is not referenced.
 *          If the j-th eigenvalue is real, then u(j) = VL(:,j),
 *          the j-th column of VL.
 *          If the j-th and (j+1)-st eigenvalues form a complex
 *          conjugate pair, then u(j) = VL(:,j) + i*VL(:,j+1) and
 *          u(j+1) = VL(:,j) - i*VL(:,j+1).
 *
 *  LDVL    (input) INTEGER
 *          The leading dimension of the array VL.  LDVL >= 1; if
 *          JOBVL = 'V', LDVL >= N.
 *
 *  VR      (output) REAL array, dimension (LDVR,N)
 *          If JOBVR = 'V', the right eigenvectors v(j) are stored one
 *          after another in the columns of VR, in the same order
 *          as their eigenvalues.
 *          If JOBVR = 'N', VR is not referenced.
 *          If the j-th eigenvalue is real, then v(j) = VR(:,j),
 *          the j-th column of VR.
 *          If the j-th and (j+1)-st eigenvalues form a complex
 *          conjugate pair, then v(j) = VR(:,j) + i*VR(:,j+1) and
 *          v(j+1) = VR(:,j) - i*VR(:,j+1).
 *
 *  LDVR    (input) INTEGER
 *          The leading dimension of the array VR.  LDVR >= 1; if
 *          JOBVR = 'V', LDVR >= N.
 *
 *  WORK    (workspace/output) REAL array, dimension (LWORK)
 *          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
 *
 *  LWORK   (input) INTEGER
 *          The dimension of the array WORK.  LWORK >= max(1,3*N), and
 *          if JOBVL = 'V' or JOBVR = 'V', LWORK >= 4*N.  For good
 *          performance, LWORK must generally be larger.
 *
 *          If LWORK = -1, then a workspace query is assumed; the routine
 *          only calculates the optimal size of the WORK array, returns
 *          this value as the first entry of the WORK array, and no error
 *          message related to LWORK is issued by XERBLA.
 *
 *  INFO    (output) INTEGER
 *          = 0:  successful exit
 *          < 0:  if INFO = -i, the i-th argument had an illegal value.
 *          > 0:  if INFO = i, the QR algorithm failed to compute all the
 *                eigenvalues, and no eigenvectors have been computed;
 *                elements i+1:N of WR and WI contain eigenvalues which
 *                have converged.
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

Sgeev()

Method Summary

static void

sgeev(java.lang.String jobvl, java.lang.String jobvr, int n, float[] a, int _a_offset, int lda, float[] wr, int _wr_offset, float[] wi, int _wi_offset, float[] vl, int _vl_offset, int ldvl, float[] vr, int _vr_offset, int ldvr, float[] work, int _work_offset, int lwork, intW info)

Methods inherited from class java.lang.Object

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

Constructor Detail

Sgeev

public Sgeev()

Method Detail

sgeev

public static void sgeev(java.lang.String jobvl,
                         java.lang.String jobvr,
                         int n,
                         float[] a,
                         int _a_offset,
                         int lda,
                         float[] wr,
                         int _wr_offset,
                         float[] wi,
                         int _wi_offset,
                         float[] vl,
                         int _vl_offset,
                         int ldvl,
                         float[] vr,
                         int _vr_offset,
                         int ldvr,
                         float[] work,
                         int _work_offset,
                         int lwork,
                         intW info)