org.netlib.lapack
Class Dtprfs

java.lang.Object
  org.netlib.lapack.Dtprfs

public class Dtprfs
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
 *  =======
 *
 *  DTPRFS provides error bounds and backward error estimates for the
 *  solution to a system of linear equations with a triangular packed
 *  coefficient matrix.
 *
 *  The solution matrix X must be computed by DTPTRS or some other
 *  means before entering this routine.  DTPRFS does not do iterative
 *  refinement because doing so cannot improve the backward error.
 *
 *  Arguments
 *  =========
 *
 *  UPLO    (input) CHARACTER*1
 *          = 'U':  A is upper triangular;
 *          = 'L':  A is lower triangular.
 *
 *  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)
 *
 *  DIAG    (input) CHARACTER*1
 *          = 'N':  A is non-unit triangular;
 *          = 'U':  A is unit triangular.
 *
 *  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 matrices B and X.  NRHS >= 0.
 *
 *  AP      (input) DOUBLE PRECISION array, dimension (N*(N+1)/2)
 *          The upper or lower triangular matrix A, packed columnwise in

 *          a linear array.  The j-th column of A is stored in the array

 *          AP as follows:
 *          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
 *          if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.

 *          If DIAG = 'U', the diagonal elements of A are not referenced

 *          and are assumed to be 1.
 *
 *  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) DOUBLE PRECISION array, dimension (LDX,NRHS)
 *          The 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 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) 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 (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
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

Dtprfs()

Method Summary

static void

dtprfs(java.lang.String uplo, java.lang.String trans, java.lang.String diag, int n, int nrhs, double[] ap, int _ap_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, 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

Dtprfs

public Dtprfs()

Method Detail

dtprfs

public static void dtprfs(java.lang.String uplo,
                          java.lang.String trans,
                          java.lang.String diag,
                          int n,
                          int nrhs,
                          double[] ap,
                          int _ap_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,
                          int[] iwork,
                          int _iwork_offset,
                          intW info)