org.netlib.lapack
Class Sgtrfs

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

public class Sgtrfs
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 * ======= * * SGTRFS improves the computed solution to a system of linear * equations when the coefficient matrix is tridiagonal, and provides * error bounds and backward error estimates for the solution. * * Arguments * ========= * * TRANS (input) CHARACTER*1 * Specifies the form of the system of equations: * = 'N': A * X = B (No transpose) * = 'T': A**T * X = B (Transpose) * = 'C': A**H * X = B (Conjugate transpose = Transpose) * * 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. * * DL (input) REAL array, dimension (N-1) * The (n-1) subdiagonal elements of A. * * D (input) REAL array, dimension (N) * The diagonal elements of A. * * DU (input) REAL array, dimension (N-1) * The (n-1) superdiagonal elements of A. * * DLF (input) REAL array, dimension (N-1) * The (n-1) multipliers that define the matrix L from the * LU factorization of A as computed by SGTTRF. * * DF (input) REAL array, dimension (N) * The n diagonal elements of the upper triangular matrix U from * the LU factorization of A. * * DUF (input) REAL array, dimension (N-1) * The (n-1) elements of the first superdiagonal of U. * * DU2 (input) REAL array, dimension (N-2) * The (n-2) elements of the second superdiagonal of U. * * IPIV (input) INTEGER array, dimension (N) * The pivot indices; for 1 <= i <= n, row i of the matrix was * interchanged with row IPIV(i). IPIV(i) will always be either * i or i+1; IPIV(i) = i indicates a row interchange was not * required. * * B (input) REAL 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) REAL array, dimension (LDX,NRHS) * On entry, the solution matrix X, as computed by SGTTRS. * On exit, the improved solution matrix X. * * LDX (input) INTEGER * The leading dimension of the array X. LDX >= max(1,N). * * FERR (output) REAL array, dimension (NRHS) * The estimated 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). The estimate is as reliable as * the estimate for RCOND, and is almost always a slight * overestimate of the true error. * * BERR (output) REAL 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) REAL array, dimension (3*N) * * IWORK (workspace) INTEGER array, dimension (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
Sgtrfs()
           
 
Method Summary
static void sgtrfs(java.lang.String trans, int n, int nrhs, float[] dl, int _dl_offset, float[] d, int _d_offset, float[] du, int _du_offset, float[] dlf, int _dlf_offset, float[] df, int _df_offset, float[] duf, int _duf_offset, float[] du2, int _du2_offset, int[] ipiv, int _ipiv_offset, float[] b, int _b_offset, int ldb, float[] x, int _x_offset, int ldx, float[] ferr, int _ferr_offset, float[] berr, int _berr_offset, float[] work, int _work_offset, int[] iwork, int _iwork_offset, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Sgtrfs

public Sgtrfs()
Method Detail

sgtrfs

public static void sgtrfs(java.lang.String trans,
                          int n,
                          int nrhs,
                          float[] dl,
                          int _dl_offset,
                          float[] d,
                          int _d_offset,
                          float[] du,
                          int _du_offset,
                          float[] dlf,
                          int _dlf_offset,
                          float[] df,
                          int _df_offset,
                          float[] duf,
                          int _duf_offset,
                          float[] du2,
                          int _du2_offset,
                          int[] ipiv,
                          int _ipiv_offset,
                          float[] b,
                          int _b_offset,
                          int ldb,
                          float[] x,
                          int _x_offset,
                          int ldx,
                          float[] ferr,
                          int _ferr_offset,
                          float[] berr,
                          int _berr_offset,
                          float[] work,
                          int _work_offset,
                          int[] iwork,
                          int _iwork_offset,
                          intW info)