Prototype

There is one prototype of gbequ available, please see below.

gbequ( const MatrixAB& ab, VectorR& r, VectorC& c, Scalar >, Scalar >,
        Scalar > );

Description

gbequ (short for $FRIENDLY_NAME) provides a C++ interface to LAPACK routines SGBEQU, DGBEQU, CGBEQU, and ZGBEQU. gbequ computes row and column scalings intended to equilibrate an M-by-N band matrix A and reduce its condition number. R returns the row scale factors and C the column scale factors, chosen to try to make the largest element in each row and column of the matrix B with elements B(i,j)=R(i)*A(i,j)*C(j) have absolute value 1.

R(i) and C(j) are restricted to be between SMLNUM = smallest safe number and BIGNUM = largest safe number. Use of these scaling factors is not guaranteed to reduce the condition number of A but works well in practice.

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

Definition

Defined in header boost/numeric/bindings/lapack/computational/gbequ.hpp.

Parameters or Requirements on Types

Complexity

Example

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

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

this will output

[5] 0 1 2 3 4 5

Notes

See Also