doublevar HEG_system::ewaldElectron(Sample_point * sample) {
sample->updateEEDist();
const int nlatvec=1;
Array1 <doublevar> r1(3), r2(3);
Array1 <doublevar> eidist(5);
//-------------Electron-electron real-space part (pairs only,
// no self-interaction)
doublevar elecElec_real=0;
for(int e1=0; e1< totnelectrons; e1++) {
for(int e2 =e1+1; e2 < totnelectrons; e2++) {
sample->getEEDist(e1,e2, eidist);
for(int d=0; d< 3; d++) r1(d)=eidist(d+2);
//----over lattice vectors
for(int kk=-nlatvec; kk <=nlatvec; kk++) {
for(int jj=-nlatvec; jj <=nlatvec; jj++) {
for(int ii=-nlatvec; ii <=nlatvec; ii++) {
for(int d=0; d< 3; d++) {
r2(d)=r1(d)+kk*latVec(0,d)+jj*latVec(1,d)+ii*latVec(2,d);
}
doublevar r=sqrt(r2(0)*r2(0)+r2(1)*r2(1)+r2(2)*r2(2));
elecElec_real+=erfcm(alpha*r)/r;
}
}
}
//----done lattice vectors
}
}
//---------electron reciprocal part (this DOES include the self-interaction)
doublevar rdotg;
Array2 <doublevar> elecpos(totnelectrons, 3);
sample->getAllElectronPos(elecpos);
doublevar elecElec_recip=0;
for(int gpt=0; gpt < ngpoints; gpt++) {
doublevar sum_sin=0, sum_cos=0;
for(int e=0; e< totnelectrons; e++) {
rdotg=gpoint(gpt, 0)*elecpos(e,0)
+gpoint(gpt, 1)*elecpos(e,1)
+gpoint(gpt, 2)*elecpos(e,2);
sum_sin+=sin(rdotg);
sum_cos+=cos(rdotg);
}
// NOTE: 1/2 from \sum_{e != e'} is cancelled with the fact that
// we use only one g-point from g,-g pair
elecElec_recip+=(sum_cos*sum_cos + sum_sin*sum_sin)*gweight(gpt);
}
//cout << "elecElec_real " << elecElec_real << endl;
//cout << "elecElec_recip " << elecElec_recip << endl;
return elecElec_real + elecElec_recip;
}
bool CollisionShape2DEditor::forward_input_event(const InputEvent& p_event) {
if (!node) {
return false;
}
if (!node->get_shape().is_valid()) {
return false;
}
if (shape_type == -1) {
return false;
}
switch( p_event.type ) {
case InputEvent::MOUSE_BUTTON: {
const InputEventMouseButton& mb = p_event.mouse_button;
Matrix32 gt = canvas_item_editor->get_canvas_transform() * node->get_global_transform();
Point2 gpoint(mb.x,mb.y);
if (mb.button_index == BUTTON_LEFT) {
if (mb.pressed) {
for (int i = 0; i < handles.size(); i++) {
if (gt.xform(handles[i]).distance_to(gpoint) < 8) {
edit_handle = i;
break;
}
}
if (edit_handle==-1) {
pressed = false;
return false;
}
original = get_handle_value(edit_handle);
pressed = true;
return true;
} else {
if (pressed) {
commit_handle(edit_handle, original);
edit_handle = -1;
pressed = false;
return true;
}
}
}
return false;
} break;
case InputEvent::MOUSE_MOTION: {
const InputEventMouseMotion& mm = p_event.mouse_motion;
if (edit_handle == -1 || !pressed) {
return false;
}
Point2 gpoint = Point2(mm.x,mm.y);
Point2 cpoint = canvas_item_editor->get_canvas_transform().affine_inverse().xform(gpoint);
cpoint = canvas_item_editor->snap_point(cpoint);
cpoint = node->get_global_transform().affine_inverse().xform(cpoint);
set_handle(edit_handle, cpoint);
return true;
} break;
}
return false;
}
int HEG_system::setupEwald(Array2 <doublevar> & crossProduct) {
//----Set up reciprocal Ewald sum
const int ndim=3;
smallestheight=1e99; //!< smallest distance that spans the cell
for(int i=0; i< ndim; i++) {
doublevar tempheight=0;
doublevar length=0;
for(int j=0; j< ndim; j++) {
tempheight+=crossProduct(i,j)*latVec(i,j);
length+=crossProduct(i,j)*crossProduct(i,j);
}
tempheight=fabs(tempheight)/sqrt(length);
if(tempheight < smallestheight ) smallestheight=tempheight;
}
debug_write(cout, "elsu ", smallestheight,"\n");
// We want only the simulation cell and its nearest neighbours
// to contribute into the real-space part of Ewald sum; alpha
// has to be chosen so that there are no contributions from distances
// larger than smallestheight, i.e., we want
// erfc(alpha*smallestheight) \sim 0
// note: erfc(5)=1.5e-12, erfc(6)=2.2e-17, erfc(6.5)=3.8e-20
// ---
// 5.0 chosen in PERIODIC system seems to be large enough; change
// from 5.0 to 6.5 doubles the number of g-points
alpha=5.0/smallestheight;
debug_write(cout, "alpha ", alpha, "\n");
const int gmax=24; //Could make this an option.
const double qweight_cut=1e-18;
ngpoints=(gmax+1)*(2*gmax+1)*(2*gmax+1)-gmax*(2*gmax+1)-gmax;
Array2 <doublevar> gpointtemp(ngpoints,3);
Array1 <doublevar> gweighttemp(ngpoints);
int currgpt=0;
int totgpt=0;
int smallgpt=0;
for(int ig=0; ig <= gmax; ig++) {
int jgmin=-gmax;
if(ig==0) jgmin=0;
for(int jg=jgmin; jg <= gmax; jg++) {
int kgmin=-gmax;
if(ig==0 && jg==0) kgmin=0;
for(int kg=kgmin; kg <= gmax; kg++) {
totgpt++;
for(int i=0; i< ndim; i++) {
gpointtemp(currgpt, i)=2*pi*(ig*recipLatVec(0,i)
+jg*recipLatVec(1,i)
+kg*recipLatVec(2,i));
}
doublevar gsqrd=0; // |g|^2
for(int i=0; i< ndim; i++) {
gsqrd+=gpointtemp(currgpt,i)*gpointtemp(currgpt,i);
}
if(gsqrd > 1e-8) { // throw away (0,0,0)
gweighttemp(currgpt)=4.0 * pi*exp(-gsqrd/(4*alpha*alpha))
/(cellVolume*gsqrd);
if(gweighttemp(currgpt) > qweight_cut) {
currgpt++;
}
} else {
smallgpt++;
}
}
}
}
if ( ngpoints != totgpt ) {
error("Wrong number of g-points while setting up Ewald summation.");
}
if ( smallgpt != 1 ) {
error("More than 1 g-point detected as 0.");
}
if ( currgpt+smallgpt >= totgpt ) {
error("Increase gmax in HEG_system.cpp, current value is too small.");
}
cout << "Reciprocal Ewald will use " << currgpt << " g-points out of "
<< totgpt << " examined." << endl;
//Adjust to the correct number of kpoints..
ngpoints=currgpt;
gpoint.Resize(ngpoints, 3);
gweight.Resize(ngpoints);
for(int i=0; i< ngpoints; i++) {
for(int d=0; d< ndim; d++) {
gpoint(i,d)=gpointtemp(i,d);
}
gweight(i)=gweighttemp(i);
}
constEwald();
return 1;
}
