Point_2D Bspline::cc(float u){
std::list<Point_2D>::iterator it = ctrlPointsNDC.begin();
float leftRatio, rightRatio;
int I;
//build a table
Point_2D lb[numberOfCtrlPoints][numberOfCtrlPoints], c_t;
for(int c = 0; c < numberOfCtrlPoints; c++, it++){
lb[0][c] = (*it);
} //init the 0th generation(j=0) control points
//determine which segment I does the u lies in
for(int i = 0 ; i < k+numberOfCtrlPoints; i++){
if( u < knotValues[i]){
I = i-1;
break;
}
}
//DPRINT("I: %d\n",I);
for(int j = 1 ; j <= k-1; j++){ //starting from the first generation
for(int i = (I - (k-1)) ; i <= I-j; i++){
rightRatio = (knotValues[i+k] - u) / (knotValues[i+k] - knotValues[i+j]) ;
leftRatio = (u - knotValues[i+j]) / (knotValues[i+k] - knotValues[i+j]) ;
lb[j][i] = add( multByScalar( lb[j-1][i], rightRatio ) , multByScalar( lb[j-1][i+1], leftRatio ) );
}
}
c_t.x = lb[k-1][I-(k-1)].x * (graph->window_width - 1);
c_t.y = lb[k-1][I-(k-1)].y * (graph->window_height -1);
return c_t;
}
void applyingRightHouseHolder(Vector* w, Vector** A_n, int nlins){
int i, j;
Vector *aux;
float lambda, wt_a_2;
lambda = dotProduct(w,w);
aux = createVector(A_n[0]->len);
for(i = 0; i < nlins; i++){
cpyVectors(w, aux);
/* wt_a_2 = dotProduct(w, A_n[i]) * 2;*/
wt_a_2 = 0;
for(j = 0; j < A_n[0]->len; j++){
wt_a_2 += w->data[j]*A_n[j]->data[i];
}
wt_a_2 *= 2;
/***/
if(lambda != 0.0) multByScalar((wt_a_2 / lambda), aux);
/*subVectors(A_n[i], aux, A_n[i]);*/
for(j = 0; j < A_n[0]->len; j++){
A_n[j]->data[i] -= aux->data[j];
}
/***/
}
free(aux);
}
Vector normalize(Vector v){
float l = length(v);
if(l > 1){
float inverse = 1 / l;
Vector norm;
norm = multByScalar(v, inverse);
return norm;
}
return v;
}
void applyingLeftHouseHolder(Vector* w, Vector** A_n, int ncols){
int j;
Vector *aux;
float lambda, wt_a_2;
lambda = dotProduct(w,w);
aux = createVector(A_n[0]->len);
for(j = 0; j < ncols; j++){
cpyVectors(w, aux);
wt_a_2 = dotProduct(w, A_n[j]) * 2;
if(lambda != 0.0) multByScalar((wt_a_2 / lambda), aux);
subVectors(A_n[j], aux, A_n[j]);
}
free(aux);
}
