##### trrfs

###### Prototype

There is one prototype of `trrfs` available, please see below.

    trrfs( const MatrixA& a, const MatrixB& b, const MatrixX& x,
            VectorFERR& ferr, VectorBERR& berr );

###### Description

`trrfs` (short for $FRIENDLY_NAME) provides a C++ interface to LAPACK routines STRRFS, DTRRFS, CTRRFS, and ZTRRFS. `trrfs` provides error bounds and backward error estimates for the solution to a system of linear equations with a triangular coefficient matrix.

The solution matrix X must be computed by ZTRTRS or some other means before entering this routine. `trrfs` does not do iterative refinement because doing so cannot improve the backward error.

The selection of the LAPACK routine is done during compile-time, and is determined by the type of values contained in type `MatrixA`. The type of values is obtained through the `value_type` meta-function `typename value_type<MatrixA>::type`. The dispatching table below illustrates to which specific routine the code path will be generated.

Table 1.305. Dispatching of trrfs

Value type of MatrixA | LAPACK routine
--- | ---
`float` | STRRFS
`double` | DTRRFS
`complex<float>` | CTRRFS
`complex<double>` | ZTRRFS

###### Definition

Defined in header `boost/numeric/bindings/lapack/computational/trrfs.hpp`.

###### Parameters or Requirements on Types

Parameters

MatrixA

  The definition of term 1

MatrixB

  The definition of term 2

MatrixC

  The definition of term 3.

  Definitions may contain paragraphs.

###### Complexity

###### Example

    #include <boost/numeric/bindings/lapack/computational/trrfs.hpp>
    using namespace boost::numeric::bindings;

    lapack::trrfs( x, y, z );

this will output

    [5] 0 1 2 3 4 5

###### Notes

###### See Also

- Originating Fortran source files strrfs.f, dtrrfs.f, ctrrfs.f, and ztrrfs.f at Netlib.