double DRMSD::calc( const std::vector<Vector>& pos, const Pbc& pbc, ReferenceValuePack& myder, const bool& squared ) const {
plumed_dbg_assert(!targets.empty());
Vector distance;
myder.clear();
double drmsd=0.;
for(std::map< std::pair <unsigned,unsigned> , double>::const_iterator it=targets.begin();it!=targets.end();++it){
const unsigned i=getAtomIndex( it->first.first );
const unsigned j=getAtomIndex( it->first.second );
if(nopbc) distance=delta( pos[i] , pos[j] );
else distance=pbc.distance( pos[i] , pos[j] );
const double len = distance.modulo();
const double diff = len - it->second;
const double der = diff / len;
drmsd += diff * diff;
myder.addAtomDerivatives( i, -der * distance );
myder.addAtomDerivatives( j, der * distance );
myder.addBoxDerivatives( - der * Tensor(distance,distance) );
}
const double inpairs = 1./static_cast<double>(targets.size());
double idrmsd;
if(squared){
drmsd = drmsd * inpairs;
idrmsd = 2.0 * inpairs;
} else {
drmsd = sqrt( drmsd * inpairs );
idrmsd = inpairs / drmsd ;
}
myder.scaleAllDerivatives( idrmsd );
return drmsd;
}
double DRMSD::calc( const std::vector<Vector>& pos, const Pbc& pbc, const bool& squared ){
plumed_dbg_assert( !targets.empty() );
Vector distance;
double drmsd=0.;
for(std::map< std::pair <unsigned,unsigned> , double>::const_iterator it=targets.begin();it!=targets.end();++it){
unsigned i=getAtomIndex( it->first.first );
unsigned j=getAtomIndex( it->first.second );
if(nopbc){ distance=delta( pos[i] , pos[j] ); }
else{ distance=pbc.distance( pos[i] , pos[j] ); }
double len = distance.modulo();
double diff = len - it->second;
drmsd += diff * diff;
addAtomicDerivatives( i, -( diff / len ) * distance );
addAtomicDerivatives( j, ( diff / len ) * distance );
addBoxDerivatives( -( diff / len ) * Tensor(distance,distance) );
}
double npairs = static_cast<double>(targets.size());
double idrmsd;
if(squared){
drmsd = drmsd / npairs;
idrmsd = 2.0 / npairs;
} else {
drmsd = sqrt( drmsd / npairs );
idrmsd = 1.0/( drmsd * npairs );
}
virial *= idrmsd;
for(unsigned i=0;i<getNumberOfAtoms();++i){atom_ders[i] *= idrmsd;}
return drmsd;
}
void Pbc::test(){
Random r;
r.setSeed(-20);
for(int i=0;i<1000;i++){
// random matrix with some zero element
Tensor box;
for(int j=0;j<3;j++) for(int k=0;k<3;k++) if(r.U01()>0.2){
box[j][k]=2.0*r.U01()-1.0;
}
int boxtype=i%10;
switch(boxtype){
case 0:
// cubic
for(int j=0;j<3;j++) for(int k=0;k<3;k++) if(j!=k) box[j][k]=0.0;
for(int j=1;j<3;j++) box[j][j]=box[0][0];
break;
case 1:
// orthorombic
for(int j=0;j<3;j++) for(int k=0;k<3;k++) if(j!=k) box[j][k]=0.0;
break;
case 2:
// hexagonal
{
int perm=r.U01()*100;
Vector a;
a(0)=r.U01()*2-2; a(1)=0.0;a(2)=0.0;
double d=r.U01()*2-2;
Vector b(0.0,d,0.0);
Vector c(0.0,0.5*d,sqrt(3.0)*d*0.5);
box.setRow((perm+0)%3,a);
box.setRow((perm+1)%3,b);
box.setRow((perm+2)%3,c);
}
break;
case 3:
// bcc
{
int perm=r.U01()*100;
double d=r.U01()*2-2;
Vector a(d,d,d);
Vector b(d,-d,d);
Vector c(d,d,-d);
box.setRow((perm+0)%3,a);
box.setRow((perm+1)%3,b);
box.setRow((perm+2)%3,c);
}
break;
case 4:
// fcc
{
int perm=r.U01()*100;
double d=r.U01()*2-2;
Vector a(d,d,0);
Vector b(d,0,d);
Vector c(0,d,d);
box.setRow((perm+0)%3,a);
box.setRow((perm+1)%3,b);
box.setRow((perm+2)%3,c);
}
break;
default:
// triclinic
break;
}
Pbc pbc;
pbc.setBox(box);
std::cerr<<"( "<<boxtype<<" )\n";
std::cerr<<"Box:";
for(int j=0;j<3;j++) for(int k=0;k<3;k++) std::cerr<<" "<<box[j][k];
std::cerr<<"\n";
std::cerr<<"Determinant: "<<determinant(box)<<"\n";
std::cerr<<"Shifts:";
for(int j=0;j<2;j++) for(int k=0;k<2;k++) for(int l=0;l<2;l++) std::cerr<<" "<<pbc.shifts[j][k][l].size();
std::cerr<<"\n";
int nshifts=0;
int ntot=10000;
for(int j=0;j<ntot;j++){
Vector v(r.U01()-0.5,r.U01()-0.5,r.U01()-0.5);
v*=5;
for(int j=0;j<3;j++) if(r.U01()>0.2) v(j)=0.0;
Vector full(v);
Vector fast=pbc.distance(Vector(0,0,0),v,&nshifts);
full=fast;
pbc.fullSearch(full);
if(modulo2(fast-full)>1e-10) {
std::cerr<<"orig "<<v[0]<<" "<<v[1]<<" "<<v[2]<<"\n";
std::cerr<<"fast "<<fast[0]<<" "<<fast[1]<<" "<<fast[2]<<"\n";
std::cerr<<"full "<<full[0]<<" "<<full[1]<<" "<<full[2]<<"\n";
std::cerr<<"diff "<<modulo2(fast)-modulo2(full)<<std::endl;
if(std::fabs(modulo2(fast)-modulo2(full))>1e-15) plumed_error();
}
}
std::cerr<<"Average number of shifts: "<<double(nshifts)/double(ntot)<<"\n";
}
}