org.netlib.lapack
Class SGBRFS

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

public class SGBRFS
extends java.lang.Object

SGBRFS is a simplified interface to the JLAPACK routine sgbrfs.
This interface converts Java-style 2D row-major arrays into
the 1D column-major linearized arrays expected by the lower
level JLAPACK routines.  Using this interface also allows you
to omit offset and leading dimension arguments.  However, because
of these conversions, these routines will be slower than the low
level ones.  Following is the description from the original Fortran
source.  Contact seymour@cs.utk.edu with any questions.

* .. * * Purpose * ======= * * SGBRFS improves the computed solution to a system of linear * equations when the coefficient matrix is banded, 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. * * KL (input) INTEGER * The number of subdiagonals within the band of A. KL >= 0. * * KU (input) INTEGER * The number of superdiagonals within the band of A. KU >= 0. * * NRHS (input) INTEGER * The number of right hand sides, i.e., the number of columns * of the matrices B and X. NRHS >= 0. * * AB (input) REAL array, dimension (LDAB,N) * The original band matrix A, stored in rows 1 to KL+KU+1. * The j-th column of A is stored in the j-th column of the * array AB as follows: * AB(ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(n,j+kl). * * LDAB (input) INTEGER * The leading dimension of the array AB. LDAB >= KL+KU+1. * * AFB (input) REAL array, dimension (LDAFB,N) * Details of the LU factorization of the band matrix A, as * computed by SGBTRF. U is stored as an upper triangular band * matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and * the multipliers used during the factorization are stored in * rows KL+KU+2 to 2*KL+KU+1. * * LDAFB (input) INTEGER * The leading dimension of the array AFB. LDAFB >= 2*KL*KU+1. * * IPIV (input) INTEGER array, dimension (N) * The pivot indices from SGBTRF; for 1<=i<=N, row i of the * matrix was interchanged with row IPIV(i). * * 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 SGBTRS. * 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
SGBRFS()
           
 
Method Summary
static void SGBRFS(java.lang.String trans, int n, int kl, int ku, int nrhs, float[][] ab, float[][] afb, int[] ipiv, float[][] b, float[][] x, float[] ferr, float[] berr, float[] work, int[] iwork, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SGBRFS

public SGBRFS()
Method Detail

SGBRFS

public static void SGBRFS(java.lang.String trans,
                          int n,
                          int kl,
                          int ku,
                          int nrhs,
                          float[][] ab,
                          float[][] afb,
                          int[] ipiv,
                          float[][] b,
                          float[][] x,
                          float[] ferr,
                          float[] berr,
                          float[] work,
                          int[] iwork,
                          intW info)