## org.netlib.lapack Class DSPRFS

```java.lang.Object
org.netlib.lapack.DSPRFS
```

`public class DSPRFSextends java.lang.Object`

```DSPRFS is a simplified interface to the JLAPACK routine dsprfs.
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
*  =======
*
*  DSPRFS improves the computed solution to a system of linear
*  equations when the coefficient matrix is symmetric indefinite
*  and packed, and provides error bounds and backward error estimates
*  for the solution.
*
*  Arguments
*  =========
*
*  UPLO    (input) CHARACTER*1
*          = 'U':  Upper triangle of A is stored;
*          = 'L':  Lower triangle of A is stored.
*
*  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 triangle of the symmetric 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.

*
*  AFP     (input) DOUBLE PRECISION array, dimension (N*(N+1)/2)
*          The factored form of the matrix A.  AFP contains the block
*          diagonal matrix D and the multipliers used to obtain the
*          factor U or L from the factorization A = U*D*U**T or
*          A = L*D*L**T as computed by DSPTRF, stored as a packed
*          triangular matrix.
*
*  IPIV    (input) INTEGER array, dimension (N)
*          Details of the interchanges and the block structure of D
*          as determined by DSPTRF.
*
*  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 DSPTRS.
*          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 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
*
*  Internal Parameters
*  ===================
*
*  ITMAX is the maximum number of steps of iterative refinement.
*
*  =====================================================================
*
*     .. Parameters ..
```

Constructor Summary
`DSPRFS()`

Method Summary
`static void` ```DSPRFS(java.lang.String uplo, int n, int nrhs, double[] ap, double[] afp, int[] ipiv, double[][] b, double[][] x, double[] ferr, double[] berr, double[] 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

### DSPRFS

`public DSPRFS()`
Method Detail

### DSPRFS

```public static void DSPRFS(java.lang.String uplo,
int n,
int nrhs,
double[] ap,
double[] afp,
int[] ipiv,
double[][] b,
double[][] x,
double[] ferr,
double[] berr,
double[] work,
int[] iwork,
intW info)```