Method getVectorRep

kernel/fglm/fglmzero.cc:542–572

Returns the fglmVector v, s.t. p = v[1]*basis(1) + .. + v[basisSize]*basis(basisSize) So the size of v depends on the current size of the basis. Assumes that such an representation exists, i.e. all monoms in p have to be smaller than basis[basisSize] and that basis[k] < basis[l] for k < l.

//     Assumes that such an representation exists, i.e. all monoms in p have to be
//      smaller than basis[basisSize] and that basis[k] < basis[l] for k < l.
fglmVector
fglmSdata::getVectorRep( const poly p )
{
    fglmVector temp( basisSize );
    poly m = p;
    int num = basisSize;
    while ( m != NULL ) {
        int comp = pCmp( m, basis[num] );
        if ( comp == 0 ) {
            fglmASSERT( num > 0, "Error(1) in fglmSdata::getVectorRep" );
            number newelem = nCopy( pGetCoeff( m ) );
            temp.setelem( num, newelem );
            num--;
            pIter( m );
        }
        else {
            if ( comp < 0 ) {
                num--;
            }
            else {
                // This is the place where we can detect if the sourceIdeal
                // is not reduced. In this case m is not in basis[]. Since basis[]
                // is ordered this is the case, if and only if basis[i]<m
                // and basis[j]>m for all j>i
                _state= FALSE;
                return temp;
            }
        }
    }
    return temp;
}

//     Searches through the border for a monomial bm which divides m and returns
//      its normalform in vector representation.