sbasis-2d.cpp revision e88f1eca443c9f97550088469932d9cea9ac0475
#include "sbasis-2d.h"
namespace Geom{
SBasis extract_u(SBasis2d const &a, double u) {
SBasis sb;
double s = u*(1-u);
for(unsigned vi = 0; vi < a.vs; vi++) {
double sk = 1;
Linear bo(0,0);
for(unsigned ui = 0; ui < a.us; ui++) {
bo += (extract_u(a.index(ui, vi), u))*sk;
sk *= s;
}
sb.push_back(bo);
}
return sb;
}
SBasis extract_v(SBasis2d const &a, double v) {
SBasis sb;
double s = v*(1-v);
for(unsigned ui = 0; ui < a.us; ui++) {
double sk = 1;
Linear bo(0,0);
for(unsigned vi = 0; vi < a.vs; vi++) {
bo += (extract_v(a.index(ui, vi), v))*sk;
sk *= s;
}
sb.push_back(bo);
}
return sb;
}
SBasis compose(Linear2d const &a, D2<SBasis> const &p) {
D2<SBasis> omp(-p[X] + 1, -p[Y] + 1);
return multiply(omp[0], omp[1])*a[0] +
multiply(p[0], omp[1])*a[1] +
multiply(omp[0], p[1])*a[2] +
multiply(p[0], p[1])*a[3];
}
SBasis
compose(SBasis2d const &fg, D2<SBasis> const &p) {
SBasis B;
SBasis s[2];
SBasis ss[2];
for(unsigned dim = 0; dim < 2; dim++)
s[dim] = p[dim]*(Linear(1) - p[dim]);
ss[1] = Linear(1);
for(unsigned vi = 0; vi < fg.vs; vi++) {
ss[0] = ss[1];
for(unsigned ui = 0; ui < fg.us; ui++) {
unsigned i = ui + vi*fg.us;
B += ss[0]*compose(fg[i], p);
ss[0] *= s[0];
}
ss[1] *= s[1];
}
return B;
}
D2<SBasis>
compose_each(D2<SBasis2d> const &fg, D2<SBasis> const &p) {
return D2<SBasis>(compose(fg[X], p), compose(fg[Y], p));
}
};
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :