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java.lang.Object | +----org.netlib.lapack.Dptrfs
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 * ======= * * DPTRFS improves the computed solution to a system of linear * equations when the coefficient matrix is symmetric positive definite * and tridiagonal, and provides error bounds and backward error * estimates for the solution. * * Arguments * ========= * * N (input) INTEGER * The order of the matrix A. N >= 0. * * NRHS (input) INTEGER * The number of right hand sides, i.e., the number of columns * of the matrix B. NRHS >= 0. * * D (input) DOUBLE PRECISION array, dimension (N) * The n diagonal elements of the tridiagonal matrix A. * * E (input) DOUBLE PRECISION array, dimension (N-1) * The (n-1) subdiagonal elements of the tridiagonal matrix A. * * DF (input) DOUBLE PRECISION array, dimension (N) * The n diagonal elements of the diagonal matrix D from the * factorization computed by DPTTRF. * * EF (input) DOUBLE PRECISION array, dimension (N-1) * The (n-1) subdiagonal elements of the unit bidiagonal factor * L from the factorization computed by DPTTRF. * * B (input) DOUBLE PRECISION array, dimension (LDB,NRHS) * The right hand side matrix B. * * LDB (input) INTEGER * The leading dimension of the array B. LDB >= max(1,N). * * X (input/output) DOUBLE PRECISION array, dimension (LDX,NRHS) * On entry, the solution matrix X, as computed by DPTTRS. * On exit, the improved solution matrix X. * * LDX (input) INTEGER * The leading dimension of the array X. LDX >= max(1,N). * * FERR (output) DOUBLE PRECISION array, dimension (NRHS) * The forward error bound for each solution vector * X(j) (the j-th column of the solution matrix X). * If XTRUE is the true solution corresponding to X(j), FERR(j) * is an estimated upper bound for the magnitude of the largest * element in (X(j) - XTRUE) divided by the magnitude of the * largest element in X(j). * * BERR (output) DOUBLE PRECISION array, dimension (NRHS) * The componentwise relative backward error of each solution * vector X(j) (i.e., the smallest relative change in * any element of A or B that makes X(j) an exact solution). * * WORK (workspace) DOUBLE PRECISION array, dimension (2*N) * * INFO (output) INTEGER * = 0: successful exit * < 0: if INFO = -i, the i-th argument had an illegal value * * Internal Parameters * =================== * * ITMAX is the maximum number of steps of iterative refinement. * * ===================================================================== * * .. Parameters ..
Dptrfs()
dptrfs(int, int, double[], int, double[], int, double[], int, double[], int, double[], int, int, double[], int, int, double[], int, double[], int, double[], int, intW)
Dptrfs
public Dptrfs()
dptrfs
public static void dptrfs(int n,
int nrhs,
double d[],
int _d_offset,
double e[],
int _e_offset,
double df[],
int _df_offset,
double ef[],
int _ef_offset,
double b[],
int _b_offset,
int ldb,
double x[],
int _x_offset,
int ldx,
double ferr[],
int _ferr_offset,
double berr[],
int _berr_offset,
double work[],
int _work_offset,
intW info)
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