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java.lang.Object | +----org.netlib.lapack.Dsbevd
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 * ======= * * DSBEVD computes all the eigenvalues and, optionally, eigenvectors of * a real symmetric band matrix A. 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. * * UPLO (input) CHARACTER*1 * = 'U': Upper triangle of A is stored; * = 'L': Lower triangle of A is stored. * * N (input) INTEGER * The order of the matrix A. N >= 0. * * KD (input) INTEGER * The number of superdiagonals of the matrix A if UPLO = 'U', * or the number of subdiagonals if UPLO = 'L'. KD >= 0. * * AB (input/output) DOUBLE PRECISION 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, AB is overwritten by values generated during the * reduction to tridiagonal form. If UPLO = 'U', the first * superdiagonal and the diagonal of the tridiagonal matrix T * are returned in rows KD and KD+1 of AB, and if UPLO = 'L', * the diagonal and first subdiagonal of T are returned in the * first two rows of AB. * * LDAB (input) INTEGER * The leading dimension of the array AB. LDAB >= KD + 1. * * W (output) DOUBLE PRECISION array, dimension (N) * If INFO = 0, the eigenvalues in ascending order. * * 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 W(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 N <= 1, LWORK must be at least 1. * If JOBZ = 'N' and N > 2, LWORK must be at least 2*N. * If JOBZ = 'V' and N > 2, LWORK must be at least * ( 1 + 4*N + 2*N*lg N + 3*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 LIWORK. * If JOBZ = 'N' or N <= 1, LIWORK must be at least 1. * If JOBZ = 'V' and N > 2, 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 an intermediate tridiagonal * form did not converge to zero. * * ===================================================================== * * .. Parameters ..
Dsbevd()
dsbevd(String, String, int, int, double[], int, int, double[], int, double[], int, int, double[], int, int, int[], int, int, intW)
Dsbevd
public Dsbevd()
dsbevd
public static void dsbevd(String jobz,
String uplo,
int n,
int kd,
double ab[],
int _ab_offset,
int ldab,
double w[],
int _w_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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