MF_LUimprove
 MD_LUimprove 
ME_LUimprove 
MCF_LUimprove 
MCD_LUimprove 
MCE_LUimprove 

Function  iterative improvement of the solution of a linear system solved by LU decomposition 

Syntax C/C++  #include <MFstd.h>
void MF_LUimprove( fVector X, fVector B, fMatrix MA, fMatrix LU, uVector Ind, ui len ); 
C++ MatObj  #include <OptiVec.h>
void vector<T>::LUimprove( const vector<T> B, const matrix<T>& MA, const matrix<T>& MLU, const vector<unsigned>& Ind ); 
Pascal/Delphi  uses MFstd;
procedure MF_LUimprove( X, B:fVector; MA, MLU:fMatrix; Ind:uVector; len:UIntSize ); 

Description  Especially for large matrices, accumulated roundoff error in LU decomposition may become quite noticable. This roundoff error will translate into inaccurate results of MF_LUsolve. If the input matrix was not overwritten by the out put matrix in the initial call to MF_LUdecompose, you may call MF_LUimprove after MF_LUsolve to improve the accuracy by iteration. MF_LUimprove needs the output vector X of MF_LUsolve, the righthandside vector B of the linear system, and both the original matrix MA and its raw LUdecomposed form MLU along with its permutation indices, Ind, as arguments. 

