/usr/include/linbox/algorithms/toeplitz-det.h is in liblinbox-dev 1.1.6~rc0-4.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | namespace LinBox { // namespace in which all LinBox code resides.
/*
template< class Field >
void toeplitz_determinant( ZZ_p& res, const Toeplitz<Field>& A );
*/
template< class PField >
typename PField::Coeff& toeplitz_determinant
( const PField& F, typename PField::Coeff& res,
const typename PField::Element& T, size_t n )
{
short int sign = 1;
typename PField::Coeff one, temp;
const typename PField::CoeffField& CField = F.getCoeffField();
CField.init(one,1);
CField.init(res,1);
typename PField::Element f1, f2( T ), fi;
F.setCoeff( f1, 2*n - 1, one );
F.init( fi, one );
while( F.deg(f2) >= n ) {
F.rem( fi, f1, f2 );
CField.mulin
( res, CField.powin( F.leadCoeff( temp, f2 ),
F.deg(f1) - F.deg(fi) ) );
if( !((F.deg(f2)-F.deg(f1))%2) && !((F.deg(f1)-n)%2) )
sign *= -1;
f1 = f2;
f2 = fi;
}
if( F.deg(f2) == (n-1) ) {
CField.mulin
( res, CField.powin( F.leadCoeff( temp, f2 ),
F.deg(f1) - F.deg(f2) ) );
if( sign == -1 ) {
typename PField::Coeff negOne;
CField.init( negOne, -1 );
CField.mulin( res, negOne );
}
}
else CField.init( res, 0 );
return res;
}
} // end of namespace LinBox
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