static void tv_iter(int nx, const PetscScalar *x, PetscScalar *y){
// deg: degree of polynomials
// nx: some context variable from Petsc interface
// x: vector with which matrix A is multiplied
// y = A*x
const int MAT_ENTRIES = pars -> get_int("MAT_ENTRIES");
//hard coded atm, move to parameters later
const int DEG = pars -> get_int("DEG");
//const int DEG = 8;
std::vector<PetscScalar> Told(MAT_ENTRIES);
std::vector<PetscScalar> Tcur(MAT_ENTRIES);
std::vector<PetscScalar> Tnew(MAT_ENTRIES);
std::vector<PetscScalar> tmp(MAT_ENTRIES);
// initialize chebyshev polynomials
tv2( nx, &x[0], &Tcur[0]);
equal_arrays(&x[0], &Told[0]);
// if deg is 1 or less return initialised values
if (DEG >=1){
// else iteratively calculate chebyshev polynomials up to deg
// T_n(B) = 2*B(T_{n-1}(B))-T_{n-2}(B)
for (int n = 2; n <= DEG; n++){
// store B(Tcur(Bx)) in tmp1
tv2(nx, &Tcur[0], &tmp[0]);
// scale tmp1
scale_array(2., &tmp[0], &tmp[0]);
//calculate new polynomial
subtract_arrays(&Told[0], &tmp[0], &y[0]);
// overwrite new variables
equal_arrays(&Tcur[0], &Told[0]);
equal_arrays(&y[0], &Tcur[0]);
}
}
}
void Mesh::skin(uint start) {
intA TT;
uintA Tt;
getTriNeighborsList(*this, Tt, TT);
arr Tn;
getTriNormals(*this, Tn);
uintA goodTris;
boolA added(T.d0);
goodTris.append(start);
added=false;
added(start)=true;
uint t, tt, r, i, k;
int m;
double p, mp=0;
for(k=0; k<goodTris.N; k++) {
t=goodTris(k);
for(r=0; r<3; r++) {
//select from all neighbors the one most parallel
m=-1;
for(i=0; i<Tt(t, r); i++) {
tt=TT(t, r, i);
p=scalarProduct(Tn[t], Tn[tt]);
if(m==-1 || p>mp) { m=tt; mp=p; }
}
if(m!=-1 && !added(m)) { goodTris.append(m); added(m)=true; }
}
}
uintA Tnew(k, 3);
for(k=0; k<goodTris.N; k++) {
t=goodTris(k);
Tnew(k, 0)=T(t, 0); Tnew(k, 1)=T(t, 1); Tnew(k, 2)=T(t, 2);
}
T=Tnew;
cout <<T <<endl;
}
void Mesh::clean() {
uint i, j, idist=0;
Vector a, b, c, m;
double mdist=0.;
arr Tc(T.d0, 3); //tri centers
arr Tn(T.d0, 3); //tri normals
uintA Vt(V.d0);
intA VT(V.d0, 100); //tri-neighbors to a vertex
Vt.setZero(); VT=-1;
for(i=0; i<T.d0; i++) {
a.set(&V(T(i, 0), 0)); b.set(&V(T(i, 1), 0)); c.set(&V(T(i, 2), 0));
//tri center
m=(a+b+c)/3.;
Tc(i, 0)=m.x; Tc(i, 1)=m.y; Tc(i, 2)=m.z;
//farthest tri
if(m.length()>mdist) { mdist=m.length(); idist=i; }
//tri normal
b-=a; c-=a; a=b^c; a.normalize();
Tn(i, 0)=a.x; Tn(i, 1)=a.y; Tn(i, 2)=a.z;
//vertex neighbor count
j=T(i, 0); VT(j, Vt(j))=i; Vt(j)++;
j=T(i, 1); VT(j, Vt(j))=i; Vt(j)++;
j=T(i, 2); VT(j, Vt(j))=i; Vt(j)++;
}
//step through tri list and flip them if necessary
boolA Tisok(T.d0); Tisok=false;
uintA Tok; //contains the list of all tris that are ok oriented
uintA Tnew(T.d0, T.d1);
Tok.append(idist);
Tisok(idist)=true;
int A=0, B=0, D;
uint r, k, l;
intA neighbors;
for(k=0; k<Tok.N; k++) {
i=Tok(k);
Tnew(k, 0)=T(i, 0); Tnew(k, 1)=T(i, 1); Tnew(k, 2)=T(i, 2);
for(r=0; r<3; r++) {
if(r==0) { A=T(i, 0); B=T(i, 1); /*C=T(i, 2);*/ }
if(r==1) { A=T(i, 1); B=T(i, 2); /*C=T(i, 0);*/ }
if(r==2) { A=T(i, 2); B=T(i, 0); /*C=T(i, 1);*/ }
//check all triangles that share A & B
setSection(neighbors, VT[A], VT[B]);
neighbors.removeAllValues(-1);
if(neighbors.N>2) MT_MSG("edge shared by more than 2 triangles " <<neighbors);
neighbors.removeValue(i);
//if(!neighbors.N) cout <<"mesh.clean warning: edge has only one triangle that shares it" <<endl;
//orient them correctly
for(l=0; l<neighbors.N; l++) {
j=neighbors(l); //j is a neighboring triangle sharing A & B
D=-1;
//align the neighboring triangle and let D be its 3rd vertex
if((int)T(j, 0)==A && (int)T(j, 1)==B) D=T(j, 2);
if((int)T(j, 0)==A && (int)T(j, 2)==B) D=T(j, 1);
if((int)T(j, 1)==A && (int)T(j, 2)==B) D=T(j, 0);
if((int)T(j, 1)==A && (int)T(j, 0)==B) D=T(j, 2);
if((int)T(j, 2)==A && (int)T(j, 0)==B) D=T(j, 1);
if((int)T(j, 2)==A && (int)T(j, 1)==B) D=T(j, 0);
if(D==-1) HALT("dammit");
//determine orientation
if(!Tisok(j)) {
T(j, 0)=B; T(j, 1)=A; T(j, 2)=D;
Tok.append(j);
Tisok(j)=true;
} else {
//check if consistent!
}
}
#if 0
//compute their rotation
if(neighbors.N>1) {
double phi, phimax;
int jmax=-1;
Vector ni, nj;
for(l=0; l<neighbors.N; l++) {
j=neighbors(l); //j is a neighboring triangle sharing A & B
a.set(&V(T(i, 0), 0)); b.set(&V(T(i, 1), 0)); c.set(&V(T(i, 2), 0));
b-=a; c-=a; a=b^c; a.normalize();
ni = a;
a.set(&V(T(j, 0), 0)); b.set(&V(T(j, 1), 0)); c.set(&V(T(j, 2), 0));
b-=a; c-=a; a=b^c; a.normalize();
nj = a;
Quaternion q;
q.setDiff(ni, -nj);
q.getDeg(phi, c);
a.set(&V(A, 0)); b.set(&V(B, 0));
if(c*(a-b) < 0.) phi+=180.;
if(jmax==-1 || phi>phimax) { jmax=j; phimax=phi; }
}
if(!Tisok(jmax)) {
Tok.append(jmax);
Tisok(jmax)=true;
}
} else {
j = neighbors(0);
if(!Tisok(j)) {
Tok.append(j);
Tisok(j)=true;
}
}
#endif
}
}
if(k<T.d0) {
cout <<"mesh.clean warning: not all triangles connected: " <<k <<"<" <<T.d0 <<endl;
cout <<"WARNING: cutting of all non-connected triangles!!" <<endl;
Tnew.resizeCopy(k, 3);
T=Tnew;
deleteUnusedVertices();
}
computeNormals();
}
