[Boost-users] ublas identity_matrix problem

From: Heiko Bauke (Heiko.Bauke_at_[hidden])
Date: 2004-09-08 13:29:50

Dear all, 
 
I discovered a problem in ublas identity_matrix class. I am doing 
linear algebra in finite fields. So my matrices contain no floats nor 
doubles. Instead I use some class that behaves like a number but does 
arithmetic in a finite field. 
 
Class instances are contructable by int, but _not_ default 
constructable by int. I don't want to have this.  
 
In matrix.hpp one finds the lines 
 
template<class T> 
typename identity_matrix<T>::value_type identity_matrix<T>::zero_=0; 
template<class T> 
typename identity_matrix<T>::value_type identity_matrix<T>::one_=1; 
 
These lines are problematic and the reason why my number class works 
not with the identity_matrix class. I think these lines should by 
changed into 
 
template<class T> 
typename identity_matrix<T>::value_type 
identity_matrix<T>::zero_=T(0); 
template<class T> 
typename identity_matrix<T>::value_type identity_matrix<T>::one_=T(1); 
 
to make the ublas code more general. 
 
 
        with regards 
 
        Heiko 
 
--  
-- Gute Sitten haben für die Gesellschaft mehr Wert als alle  
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-- Supercomputing in Magdeburg @ http://tina.nat.uni-magdeburg.de 
--                 Heiko Bauke @ http://www.uni-magdeburg.de/bauke