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Merged
rieder merged 3 commits into from
Jul 24, 2025
Merged

Include test particle calculations in Ph4 #1161

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932c935
Updates to ph4
ErwanH29 Jul 3, 2025
1f7c162
Implemented more massless algorithms
ErwanH29 Jul 3, 2025
d74d152
Merge branch 'main' into main
rieder Jul 23, 2025
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20 changes: 13 additions & 7 deletions src/amuse_ph4/interface.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -780,19 +780,22 @@ int get_center_of_mass_position(double * x, double * y, double * z)
// (Could also use jdata::get_com.)

if (!jd || jd->nj <= 0) {
*x = *y = *z = 0;
return 0;
*x = *y = *z = 0;
return 0;
}

real mtot = 0;
vec cmx(0,0,0);
for (int j = 0; j < jd->nj; j++) {
mtot += jd->mass[j];
for (int k = 0; k < 3; k++) cmx[k] += jd->mass[j]*jd->pos[j][k];
if (jd->mass[j] > _TINY_){
mtot += jd->mass[j];
for (int k = 0; k < 3; k++) cmx[k] += jd->mass[j]*jd->pos[j][k];
}
}
*x = cmx[0]/mtot;
*y = cmx[1]/mtot;
*z = cmx[2]/mtot;

return 0;
}

Expand All @@ -808,12 +811,15 @@ int get_center_of_mass_velocity(double * vx, double * vy, double * vz)
real mtot = 0;
vec cmv(0,0,0);
for (int j = 0; j < jd->nj; j++) {
mtot += jd->mass[j];
for (int k = 0; k < 3; k++) cmv[k] += jd->mass[j]*jd->vel[j][k];
if (jd->mass[j] > _TINY_){
mtot += jd->mass[j];
for (int k = 0; k < 3; k++) cmv[k] += jd->mass[j]*jd->vel[j][k];
}
}
*vx = cmv[0]/mtot;
*vy = cmv[1]/mtot;
*vz = cmv[2]/mtot;

return 0;
}

Expand Down
68 changes: 38 additions & 30 deletions src/amuse_ph4/src/idata.cc
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Expand Up @@ -204,30 +204,33 @@ void idata::get_partial_acc_and_jerk()
ldnn[i] = _INFINITY_;
for (int k = 0; k < 3; k++) lacc[i][k] = ljerk[i][k] = 0;
for (int j = j_start; j < j_end; j++) {
r2 = xv = 0;
for (int k = 0; k < 3; k++) {
dx[k] = jdat->pred_pos[j][k] - ipos[i][k];
dv[k] = jdat->pred_vel[j][k] - ivel[i][k];
r2 += dx[k]*dx[k];
xv += dx[k]*dv[k];
}
r2i = 1/(r2+eps2+_TINY_);
ri = sqrt(r2i);
mri = jdat->mass[j]*ri;
mr3i = mri*r2i;
a3 = -3*xv*r2i;
// PRC(jdat->mpi_rank); PRC(ri); PRL(mri);
if (r2 > _TINY_) {
lpot[i] -= mri;
if (r2 < ldnn[i]) {
ldnn[i] = r2;
lnn[i] = j;
// Skip particles with zero mass.
if (jdat->mass[j] > _TINY_){
r2 = xv = 0;
for (int k = 0; k < 3; k++) {
dx[k] = jdat->pred_pos[j][k] - ipos[i][k];
dv[k] = jdat->pred_vel[j][k] - ivel[i][k];
r2 += dx[k]*dx[k];
xv += dx[k]*dv[k];
}
r2i = 1/(r2+eps2+_TINY_);
ri = sqrt(r2i);
mri = jdat->mass[j]*ri;
mr3i = mri*r2i;
a3 = -3*xv*r2i;
// PRC(jdat->mpi_rank); PRC(ri); PRL(mri);
if (r2 > _TINY_) {
lpot[i] -= mri;
if (r2 < ldnn[i]) {
ldnn[i] = r2;
lnn[i] = j;
}
}
for (int k = 0; k < 3; k++) {
lacc[i][k] += mr3i*dx[k];
ljerk[i][k] += mr3i*(dv[k]+a3*dx[k]);
}
}
}
for (int k = 0; k < 3; k++) {
lacc[i][k] += mr3i*dx[k];
ljerk[i][k] += mr3i*(dv[k]+a3*dx[k]);
}
}
ldnn[i] = sqrt(ldnn[i]);
}
Expand Down Expand Up @@ -523,8 +526,11 @@ real idata::get_pot()
// and called get_acc_and_jerk() for the entire system.

real pot2 = 0;
for (int i = 0; i < ni; i++)
pot2 += jdat->mass[ilist[i]]*ipot[i];

// Ignore massless particles
for (int i = 0; i < ni; i++){
pot2 += jdat->mass[ilist[i]] * ipot[i];
}
return pot2/2;
}

Expand All @@ -538,9 +544,9 @@ real idata::get_kin()

real kin2 = 0;
for (int i = 0; i < ni; i++) {
real v2 = 0;
for (int k = 0; k < 3; k++) v2 += pow(ivel[i][k],2);
kin2 += jdat->mass[ilist[i]]*v2;
real v2 = 0;
for (int k = 0; k < 3; k++) v2 += pow(ivel[i][k],2);
kin2 += jdat->mass[ilist[i]]*v2;
}
return kin2/2;
}
Expand Down Expand Up @@ -636,12 +642,13 @@ void idata::check_encounters()
for (int i = 0; i < ni; i++) {

int jnn = inn[i]; // j index, note
if (jnn >= 0) { // valid neighbor
if (jnn >= 0) { // valid neighbor

// Ignore collisions between two massless particles
if ((jdat->mass[jnn] > _TINY_) || (imass[i] > _TINY_)) {
// Note no dtmin test.

real r = rmin/idnn[i];

if (r > rmax_close) {
rmax_close = r;
imax_close = i;
Expand All @@ -658,6 +665,7 @@ void idata::check_encounters()
imax_coll = i;
}
}
}
}

if (rmax_close >= 1) { // close criterion
Expand Down
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