org.netlib.lapack
Class Dptrfs

java.lang.Object
  extended by org.netlib.lapack.Dptrfs

public class Dptrfs
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 * ======= * * 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 ..


Constructor Summary
Dptrfs()
           
 
Method Summary
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)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Dptrfs

public Dptrfs()
Method Detail

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)