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java.lang.Object | +----org.netlib.lapack.Dgeevx
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 * ======= * * DGEEVX computes for an N-by-N real nonsymmetric matrix A, the * eigenvalues and, optionally, the left and/or right eigenvectors. * * Optionally also, it computes a balancing transformation to improve * the conditioning of the eigenvalues and eigenvectors (ILO, IHI, * SCALE, and ABNRM), reciprocal condition numbers for the eigenvalues * (RCONDE), and reciprocal condition numbers for the right * eigenvectors (RCONDV). * * 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. * * Balancing a matrix means permuting the rows and columns to make it * more nearly upper triangular, and applying a diagonal similarity * transformation D * A * D**(-1), where D is a diagonal matrix, to * make its rows and columns closer in norm and the condition numbers * of its eigenvalues and eigenvectors smaller. The computed * reciprocal condition numbers correspond to the balanced matrix. * Permuting rows and columns will not change the condition numbers * (in exact arithmetic) but diagonal scaling will. For further * explanation of balancing, see section 4.10.2 of the LAPACK * Users' Guide. * * Arguments * ========= * * BALANC (input) CHARACTER*1 * Indicates how the input matrix should be diagonally scaled * and/or permuted to improve the conditioning of its * eigenvalues. * = 'N': Do not diagonally scale or permute; * = 'P': Perform permutations to make the matrix more nearly * upper triangular. Do not diagonally scale; * = 'S': Diagonally scale the matrix, i.e. replace A by * D*A*D**(-1), where D is a diagonal matrix chosen * to make the rows and columns of A more equal in * norm. Do not permute; * = 'B': Both diagonally scale and permute A. * * Computed reciprocal condition numbers will be for the matrix * after balancing and/or permuting. Permuting does not change * condition numbers (in exact arithmetic), but balancing does. * * JOBVL (input) CHARACTER*1 * = 'N': left eigenvectors of A are not computed; * = 'V': left eigenvectors of A are computed. * If SENSE = 'E' or 'B', JOBVL must = 'V'. * * JOBVR (input) CHARACTER*1 * = 'N': right eigenvectors of A are not computed; * = 'V': right eigenvectors of A are computed. * If SENSE = 'E' or 'B', JOBVR must = 'V'. * * SENSE (input) CHARACTER*1 * Determines which reciprocal condition numbers are computed. * = 'N': None are computed; * = 'E': Computed for eigenvalues only; * = 'V': Computed for right eigenvectors only; * = 'B': Computed for eigenvalues and right eigenvectors. * * If SENSE = 'E' or 'B', both left and right eigenvectors * must also be computed (JOBVL = 'V' and JOBVR = 'V'). * * N (input) INTEGER * The order of the matrix A. N >= 0. * * A (input/output) DOUBLE PRECISION array, dimension (LDA,N) * On entry, the N-by-N matrix A. * On exit, A has been overwritten. If JOBVL = 'V' or * JOBVR = 'V', A contains the real Schur form of the balanced * version of the input matrix A. * * LDA (input) INTEGER * The leading dimension of the array A. LDA >= max(1,N). * * WR (output) DOUBLE PRECISION array, dimension (N) * WI (output) DOUBLE PRECISION array, dimension (N) * WR and WI contain the real and imaginary parts, * respectively, of the computed eigenvalues. Complex * conjugate pairs of eigenvalues will appear consecutively * with the eigenvalue having the positive imaginary part * first. * * VL (output) DOUBLE PRECISION 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) DOUBLE PRECISION 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, and if * JOBVR = 'V', LDVR >= N. * * ILO,IHI (output) INTEGER * ILO and IHI are integer values determined when A was * balanced. The balanced A(i,j) = 0 if I > J and * J = 1,...,ILO-1 or I = IHI+1,...,N. * * SCALE (output) DOUBLE PRECISION array, dimension (N) * Details of the permutations and scaling factors applied * when balancing A. If P(j) is the index of the row and column * interchanged with row and column j, and D(j) is the scaling * factor applied to row and column j, then * SCALE(J) = P(J), for J = 1,...,ILO-1 * = D(J), for J = ILO,...,IHI * = P(J) for J = IHI+1,...,N. * The order in which the interchanges are made is N to IHI+1, * then 1 to ILO-1. * * ABNRM (output) DOUBLE PRECISION * The one-norm of the balanced matrix (the maximum * of the sum of absolute values of elements of any column). * * RCONDE (output) DOUBLE PRECISION array, dimension (N) * RCONDE(j) is the reciprocal condition number of the j-th * eigenvalue. * * RCONDV (output) DOUBLE PRECISION array, dimension (N) * RCONDV(j) is the reciprocal condition number of the j-th * right eigenvector. * * WORK (workspace/output) DOUBLE PRECISION array, dimension (LWORK) * On exit, if INFO = 0, WORK(1) returns the optimal LWORK. * * LWORK (input) INTEGER * The dimension of the array WORK. If SENSE = 'N' or 'E', * LWORK >= max(1,2*N), and if JOBVL = 'V' or JOBVR = 'V', * LWORK >= 3*N. If SENSE = 'V' or 'B', LWORK >= N*(N+6). * For good performance, LWORK must generally be larger. * * IWORK (workspace) INTEGER array, dimension (2*N-2) * If SENSE = 'N' or 'E', not referenced. * * 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 or condition numbers * have been computed; elements 1:ILO-1 and i+1:N of WR * and WI contain eigenvalues which have converged. * * ===================================================================== * * .. Parameters ..
Dgeevx()
dgeevx(String, String, String, String, int, double[], int, int, double[], int, double[], int, double[], int, int, double[], int, int, intW, intW, double[], int, doubleW, double[], int, double[], int, double[], int, int, int[], int, intW)
Dgeevx
public Dgeevx()
dgeevx
public static void dgeevx(String balanc,
String jobvl,
String jobvr,
String sense,
int n,
double a[],
int _a_offset,
int lda,
double wr[],
int _wr_offset,
double wi[],
int _wi_offset,
double vl[],
int _vl_offset,
int ldvl,
double vr[],
int _vr_offset,
int ldvr,
intW ilo,
intW ihi,
double scale[],
int _scale_offset,
doubleW abnrm,
double rconde[],
int _rconde_offset,
double rcondv[],
int _rcondv_offset,
double work[],
int _work_offset,
int lwork,
int iwork[],
int _iwork_offset,
intW info)
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