Commit bc8abdbe authored by Bert Vandenbroucke's avatar Bert Vandenbroucke
Browse files

Cleaned up some equations in Gizmo's hydro_iact and hydro_gradients. Moved the...

Cleaned up some equations in Gizmo's hydro_iact and hydro_gradients. Moved the gradient prediction to before the velocity boost.
parent a0148917
......@@ -98,8 +98,7 @@ __attribute__((always_inline)) INLINE static void hydro_gradients_predict(
/* perform gradient reconstruction in space and time */
/* Compute interface position (relative to pj, since we don't need the actual
* position) eqn. (8) */
const float xfac = hj / (hi + hj);
const float xij_j[3] = {xfac * dx[0], xfac * dx[1], xfac * dx[2]};
const float xij_j[3] = {xij_i[0] + dx[0], xij_i[1] + dx[1], xij_i[2] + dx[2]};
float dWi[5];
dWi[0] = pi->primitives.gradients.rho[0] * xij_i[0] +
......
......@@ -375,11 +375,9 @@ __attribute__((always_inline)) INLINE static void runner_iact_fluxes_common(
/* Compute interface velocity */
/* eqn. (9) */
float xijdotdx = xij_i[0] * dx[0] + xij_i[1] * dx[1] + xij_i[2] * dx[2];
xijdotdx *= r_inv * r_inv;
const float vij[3] = {vi[0] + (vi[0] - vj[0]) * xijdotdx,
vi[1] + (vi[1] - vj[1]) * xijdotdx,
vi[2] + (vi[2] - vj[2]) * xijdotdx};
const float vij[3] = {vi[0] + (vi[0] - vj[0]) * xfac,
vi[1] + (vi[1] - vj[1]) * xfac,
vi[2] + (vi[2] - vj[2]) * xfac};
/* complete calculation of position of interface */
/* NOTE: dx is not necessarily just pi->x - pj->x but can also contain
......@@ -391,6 +389,8 @@ __attribute__((always_inline)) INLINE static void runner_iact_fluxes_common(
// for ( k = 0 ; k < 3 ; k++ )
// xij[k] += pi->x[k];
hydro_gradients_predict(pi, pj, hi, hj, dx, r, xij_i, Wi, Wj);
/* Boost the primitive variables to the frame of reference of the interface */
/* Note that velocities are indices 1-3 in W */
Wi[1] -= vij[0];
......@@ -400,8 +400,6 @@ __attribute__((always_inline)) INLINE static void runner_iact_fluxes_common(
Wj[2] -= vij[1];
Wj[3] -= vij[2];
hydro_gradients_predict(pi, pj, hi, hj, dx, r, xij_i, Wi, Wj);
/* we don't need to rotate, we can use the unit vector in the Riemann problem
* itself (see GIZMO) */
......
......@@ -98,8 +98,7 @@ __attribute__((always_inline)) INLINE static void hydro_gradients_predict(
/* perform gradient reconstruction in space and time */
/* Compute interface position (relative to pj, since we don't need the actual
* position) eqn. (8) */
const float xfac = hj / (hi + hj);
const float xij_j[3] = {xfac * dx[0], xfac * dx[1], xfac * dx[2]};
const float xij_j[3] = {xij_i[0] + dx[0], xij_i[1] + dx[1], xij_i[2] + dx[2]};
float dWi[5];
dWi[0] = pi->primitives.gradients.rho[0] * xij_i[0] +
......
......@@ -375,21 +375,11 @@ __attribute__((always_inline)) INLINE static void runner_iact_fluxes_common(
/* Compute interface velocity */
/* eqn. (9) */
float xijdotdx = xij_i[0] * dx[0] + xij_i[1] * dx[1] + xij_i[2] * dx[2];
xijdotdx *= r_inv * r_inv;
const float vij[3] = {vi[0] + (vi[0] - vj[0]) * xijdotdx,
vi[1] + (vi[1] - vj[1]) * xijdotdx,
vi[2] + (vi[2] - vj[2]) * xijdotdx};
/* complete calculation of position of interface */
/* NOTE: dx is not necessarily just pi->x - pj->x but can also contain
correction terms for periodicity. If we do the interpolation,
we have to use xij w.r.t. the actual particle.
=> we need a separate xij for pi and pj... */
/* tldr: we do not need the code below, but we do need the same code as above
but then with i and j swapped */
// for ( k = 0 ; k < 3 ; k++ )
// xij[k] += pi->x[k];
const float vij[3] = {vi[0] + xfac * (vi[0] - vj[0]),
vi[1] + xfac * (vi[1] - vj[1]),
vi[2] + xfac * (vi[2] - vj[2])};
hydro_gradients_predict(pi, pj, hi, hj, dx, r, xij_i, Wi, Wj);
/* Boost the primitive variables to the frame of reference of the interface */
/* Note that velocities are indices 1-3 in W */
......@@ -400,8 +390,6 @@ __attribute__((always_inline)) INLINE static void runner_iact_fluxes_common(
Wj[2] -= vij[1];
Wj[3] -= vij[2];
hydro_gradients_predict(pi, pj, hi, hj, dx, r, xij_i, Wi, Wj);
/* we don't need to rotate, we can use the unit vector in the Riemann problem
* itself (see GIZMO) */
......
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