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java.lang.Object | +----org.netlib.lapack.Dstevd
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 * ======= * * DSTEVD computes all eigenvalues and, optionally, eigenvectors of a * real symmetric tridiagonal matrix. 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 * ========= * * JOBZ (input) CHARACTER*1 * = 'N': Compute eigenvalues only; * = 'V': Compute eigenvalues and eigenvectors. * * N (input) INTEGER * The order of the matrix. N >= 0. * * D (input/output) DOUBLE PRECISION array, dimension (N) * On entry, the n diagonal elements of the tridiagonal matrix * A. * On exit, if INFO = 0, the eigenvalues in ascending order. * * E (input/output) DOUBLE PRECISION array, dimension (N) * On entry, the (n-1) subdiagonal elements of the tridiagonal * matrix A, stored in elements 1 to N-1 of E; E(N) need not * be set, but is used by the routine. * On exit, the contents of E are destroyed. * * Z (output) DOUBLE PRECISION array, dimension (LDZ, N) * If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal * eigenvectors of the matrix A, with the i-th column of Z * holding the eigenvector associated with D(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) DOUBLE PRECISION array, * dimension (LWORK) * On exit, if LWORK > 0, WORK(1) returns the optimal LWORK. * * LWORK (input) INTEGER * The dimension of the array WORK. * If JOBZ = 'N' or N <= 1 then LWORK must be at least 1. * If JOBZ = 'V' and N > 1 then LWORK must be at least * ( 1 + 3*N + 2*N*lg N + 2*N**2 ), * where lg( N ) = smallest integer k such * that 2**k >= N. * * IWORK (workspace/output) INTEGER array, dimension (LIWORK) * On exit, if LIWORK > 0, IWORK(1) returns the optimal LIWORK. * * LIWORK (input) INTEGER * The dimension of the array IWORK. * If JOBZ = 'N' or N <= 1 then LIWORK must be at least 1. * If JOBZ = 'V' and N > 1 then LIWORK must be at least 2+5*N. * * INFO (output) INTEGER * = 0: successful exit * < 0: if INFO = -i, the i-th argument had an illegal value * > 0: if INFO = i, the algorithm failed to converge; i * off-diagonal elements of E did not converge to zero. * * ===================================================================== * * .. Parameters ..
Dstevd()
dstevd(String, int, double[], int, double[], int, double[], int, int, double[], int, int, int[], int, int, intW)
Dstevd
public Dstevd()
dstevd
public static void dstevd(String jobz,
int n,
double d[],
int _d_offset,
double e[],
int _e_offset,
double z[],
int _z_offset,
int ldz,
double work[],
int _work_offset,
int lwork,
int iwork[],
int _iwork_offset,
int liwork,
intW info)
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