Prototype

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

pbequ( const MatrixAB& ab, VectorS& s, Scalar >, Scalar > );

Description

pbequ (short for $FRIENDLY_NAME) provides a C++ interface to LAPACK routines SPBEQU, DPBEQU, CPBEQU, and ZPBEQU. pbequ computes row and column scalings intended to equilibrate a Hermitian positive definite band matrix A and reduce its condition number (with respect to the two-norm). S contains the scale factors, S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This choice of S puts the condition number of B within a factor N of the smallest possible condition number over all possible diagonal scalings.

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/pbequ.hpp.

Parameters or Requirements on Types

Complexity

Example

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

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

this will output

[5] 0 1 2 3 4 5

Notes

See Also