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astaroth/src/utils/modelsolver.c

1009 lines
33 KiB
C

/*
Copyright (C) 2014-2020, Johannes Pekkila, Miikka Vaisala.
This file is part of Astaroth.
Astaroth is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Astaroth is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Astaroth. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file
* \brief Brief info.
*
* Detailed info.
*
*/
#include "astaroth_utils.h"
#include <math.h>
#include <stdbool.h>
#include "errchk.h"
#include "memory.h" // acMeshCreate, acMeshDestroy, acMeshApplyPeriodicBounds
// Standalone flags
#define LDENSITY (1)
#define LHYDRO (1)
#define LMAGNETIC (1)
#define LENTROPY (1)
#define LTEMPERATURE (0)
#define LFORCING (1)
#define LUPWD (1)
#define AC_THERMAL_CONDUCTIVITY ((Scalar)(0.001)) // TODO: make an actual config parameter
typedef AcReal Scalar;
// typedef AcReal3 Vector;
// typedef AcMatrix Matrix;
#if AC_DOUBLE_PRECISION == 1
typedef double Vector __attribute__((vector_size(4 * sizeof(double))));
#else
typedef float Vector __attribute__((vector_size(4 * sizeof(float))));
#define fabs fabsf
#define exp expf
#define sqrt sqrtf
#endif
typedef struct {
Vector row[3];
} Matrix;
static AcMeshInfo* mesh_info = NULL;
static inline int
getInt(const AcIntParam param)
{
return mesh_info->int_params[param];
}
static inline Scalar
getReal(const AcRealParam param)
{
return mesh_info->real_params[param];
}
static inline int
IDX(const int i, const int j, const int k)
{
return acVertexBufferIdx(i, j, k, (*mesh_info));
}
typedef struct {
Scalar value;
Vector gradient;
Matrix hessian;
#if LUPWD
Vector upwind;
#endif
} ScalarData;
typedef struct {
ScalarData xdata;
ScalarData ydata;
ScalarData zdata;
} VectorData;
static inline Scalar
first_derivative(const Scalar* pencil, const Scalar inv_ds)
{
#if STENCIL_ORDER == 2
const Scalar coefficients[] = {0, (Scalar)(1. / 2.)};
#elif STENCIL_ORDER == 4
const Scalar coefficients[] = {0, (Scalar)(2.0 / 3.0), (Scalar)(-1.0 / 12.0)};
#elif STENCIL_ORDER == 6
const Scalar coefficients[] = {0, (Scalar)(3.0 / 4.0), (Scalar)(-3.0 / 20.0),
(Scalar)(1.0 / 60.0)};
#elif STENCIL_ORDER == 8
const Scalar coefficients[] = {0, (Scalar)(4.0 / 5.0), (Scalar)(-1.0 / 5.0),
(Scalar)(4.0 / 105.0), (Scalar)(-1.0 / 280.0)};
#endif
#define MID (STENCIL_ORDER / 2)
Scalar res = 0;
//#pragma unroll
for (int i = 1; i <= MID; ++i)
res += coefficients[i] * (pencil[MID + i] - pencil[MID - i]);
return res * inv_ds;
}
static inline Scalar
second_derivative(const Scalar* pencil, const Scalar inv_ds)
{
#if STENCIL_ORDER == 2
const Scalar coefficients[] = {-2, 1};
#elif STENCIL_ORDER == 4
const Scalar coefficients[] = {(Scalar)(-5.0 / 2.0), (Scalar)(4.0 / 3.0),
(Scalar)(-1.0 / 12.0)};
#elif STENCIL_ORDER == 6
const Scalar coefficients[] = {(Scalar)(-49.0 / 18.0), (Scalar)(3.0 / 2.0),
(Scalar)(-3.0 / 20.0), (Scalar)(1.0 / 90.0)};
#elif STENCIL_ORDER == 8
const Scalar coefficients[] = {(Scalar)(-205.0 / 72.0), (Scalar)(8.0 / 5.0),
(Scalar)(-1.0 / 5.0), (Scalar)(8.0 / 315.0),
(Scalar)(-1.0 / 560.0)};
#endif
#define MID (STENCIL_ORDER / 2)
Scalar res = coefficients[0] * pencil[MID];
//#pragma unroll
for (int i = 1; i <= MID; ++i)
res += coefficients[i] * (pencil[MID + i] + pencil[MID - i]);
return res * inv_ds * inv_ds;
}
/** inv_ds: inverted mesh spacing f.ex. 1. / mesh.int_params[AC_dsx] */
static inline Scalar
cross_derivative(const Scalar* pencil_a, const Scalar* pencil_b, const Scalar inv_ds_a,
const Scalar inv_ds_b)
{
#if STENCIL_ORDER == 2
const Scalar coefficients[] = {0, (Scalar)(1.0 / 4.0)};
#elif STENCIL_ORDER == 4
const Scalar coefficients[] = {
0, (Scalar)(1.0 / 32.0),
(Scalar)(1.0 / 64.0)}; // TODO correct coefficients, these are just placeholders
#elif STENCIL_ORDER == 6
const Scalar fac = ((Scalar)(1. / 720.));
const Scalar coefficients[] = {0 * fac, (Scalar)(270.0) * fac, (Scalar)(-27.0) * fac,
(Scalar)(2.0) * fac};
#elif STENCIL_ORDER == 8
const Scalar fac = ((Scalar)(1. / 20160.));
const Scalar coefficients[] = {0 * fac, (Scalar)(8064.) * fac, (Scalar)(-1008.) * fac,
(Scalar)(128.) * fac, (Scalar)(-9.) * fac};
#endif
#define MID (STENCIL_ORDER / 2)
Scalar res = (Scalar)(0.);
//#pragma unroll
for (int i = 1; i <= MID; ++i) {
res += coefficients[i] *
(pencil_a[MID + i] + pencil_a[MID - i] - pencil_b[MID + i] - pencil_b[MID - i]);
}
return res * inv_ds_a * inv_ds_b;
}
static inline Scalar
derx(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil[offset] = arr[IDX(i + offset - STENCIL_ORDER / 2, j, k)];
return first_derivative(pencil, getReal(AC_inv_dsx));
}
static inline Scalar
derxx(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil[offset] = arr[IDX(i + offset - STENCIL_ORDER / 2, j, k)];
return second_derivative(pencil, getReal(AC_inv_dsx));
}
static inline Scalar
derxy(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil_a[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil_a[offset] = arr[IDX(i + offset - STENCIL_ORDER / 2, j + offset - STENCIL_ORDER / 2,
k)];
Scalar pencil_b[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil_b[offset] = arr[IDX(i + offset - STENCIL_ORDER / 2, j + STENCIL_ORDER / 2 - offset,
k)];
return cross_derivative(pencil_a, pencil_b, getReal(AC_inv_dsx), getReal(AC_inv_dsy));
}
static inline Scalar
derxz(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil_a[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil_a[offset] = arr[IDX(i + offset - STENCIL_ORDER / 2, j,
k + offset - STENCIL_ORDER / 2)];
Scalar pencil_b[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil_b[offset] = arr[IDX(i + offset - STENCIL_ORDER / 2, j,
k + STENCIL_ORDER / 2 - offset)];
return cross_derivative(pencil_a, pencil_b, getReal(AC_inv_dsx), getReal(AC_inv_dsz));
}
static inline Scalar
dery(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil[offset] = arr[IDX(i, j + offset - STENCIL_ORDER / 2, k)];
return first_derivative(pencil, getReal(AC_inv_dsy));
}
static inline Scalar
deryy(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil[offset] = arr[IDX(i, j + offset - STENCIL_ORDER / 2, k)];
return second_derivative(pencil, getReal(AC_inv_dsy));
}
static inline Scalar
deryz(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil_a[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil_a[offset] = arr[IDX(i, j + offset - STENCIL_ORDER / 2,
k + offset - STENCIL_ORDER / 2)];
Scalar pencil_b[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil_b[offset] = arr[IDX(i, j + offset - STENCIL_ORDER / 2,
k + STENCIL_ORDER / 2 - offset)];
return cross_derivative(pencil_a, pencil_b, getReal(AC_inv_dsy), getReal(AC_inv_dsz));
}
static inline Scalar
derz(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil[offset] = arr[IDX(i, j, k + offset - STENCIL_ORDER / 2)];
return first_derivative(pencil, getReal(AC_inv_dsz));
}
static inline Scalar
derzz(const int i, const int j, const int k, const Scalar* arr)
{
Scalar pencil[STENCIL_ORDER + 1];
//#pragma unroll
for (int offset = 0; offset < STENCIL_ORDER + 1; ++offset)
pencil[offset] = arr[IDX(i, j, k + offset - STENCIL_ORDER / 2)];
return second_derivative(pencil, getReal(AC_inv_dsz));
}
#if LUPWD
static inline Scalar
der6x_upwd(const int i, const int j, const int k, const Scalar* arr)
{
Scalar inv_ds = getReal(AC_inv_dsx);
return (Scalar)(1.0 / 60.0) * inv_ds *
(-(Scalar)(20.0) * arr[IDX(i, j, k)] +
(Scalar)(15.0) * (arr[IDX(i + 1, j, k)] + arr[IDX(i - 1, j, k)]) -
(Scalar)(6.0) * (arr[IDX(i + 2, j, k)] + arr[IDX(i - 2, j, k)]) +
arr[IDX(i + 3, j, k)] + arr[IDX(i - 3, j, k)]);
}
static inline Scalar
der6y_upwd(const int i, const int j, const int k, const Scalar* arr)
{
Scalar inv_ds = getReal(AC_inv_dsy);
return (Scalar)(1.0 / 60.0) * inv_ds *
(-(Scalar)(20.0) * arr[IDX(i, j, k)] +
(Scalar)(15.0) * (arr[IDX(i, j + 1, k)] + arr[IDX(i, j - 1, k)]) -
(Scalar)(6.0) * (arr[IDX(i, j + 2, k)] + arr[IDX(i, j - 2, k)]) +
arr[IDX(i, j + 3, k)] + arr[IDX(i, j - 3, k)]);
}
static inline Scalar
der6z_upwd(const int i, const int j, const int k, const Scalar* arr)
{
Scalar inv_ds = getReal(AC_inv_dsz);
return (Scalar)(1.0 / 60.0) * inv_ds *
(-(Scalar)(20.0) * arr[IDX(i, j, k)] +
(Scalar)(15.0) * (arr[IDX(i, j, k + 1)] + arr[IDX(i, j, k - 1)]) -
(Scalar)(6.0) * (arr[IDX(i, j, k + 2)] + arr[IDX(i, j, k - 2)]) +
arr[IDX(i, j, k + 3)] + arr[IDX(i, j, k - 3)]);
}
#endif
static inline Scalar
compute_value(const int i, const int j, const int k, const Scalar* arr)
{
return arr[IDX(i, j, k)];
}
static inline Vector
compute_gradient(const int i, const int j, const int k, const Scalar* arr)
{
return (Vector){derx(i, j, k, arr), dery(i, j, k, arr), derz(i, j, k, arr)};
}
#if LUPWD
static inline Vector
compute_upwind(const int i, const int j, const int k, const Scalar* arr)
{
return (Vector){der6x_upwd(i, j, k, arr), der6y_upwd(i, j, k, arr), der6z_upwd(i, j, k, arr)};
}
#endif
static inline Matrix
compute_hessian(const int i, const int j, const int k, const Scalar* arr)
{
Matrix hessian;
hessian.row[0] = (Vector){derxx(i, j, k, arr), derxy(i, j, k, arr), derxz(i, j, k, arr)};
hessian.row[1] = (Vector){hessian.row[0][1], deryy(i, j, k, arr), deryz(i, j, k, arr)};
hessian.row[2] = (Vector){hessian.row[0][2], hessian.row[1][2], derzz(i, j, k, arr)};
return hessian;
}
static inline ScalarData
read_scal_data(const int i, const int j, const int k, Scalar* buf[NUM_VTXBUF_HANDLES],
const int handle)
{
ScalarData data;
data.value = compute_value(i, j, k, buf[handle]);
data.gradient = compute_gradient(i, j, k, buf[handle]);
// No significant effect on performance even though we do not need the
// diagonals with all arrays
data.hessian = compute_hessian(i, j, k, buf[handle]);
#if LUPWD
data.upwind = compute_upwind(i, j, k, buf[handle]);
#endif
return data;
}
static inline VectorData
read_vec_data(const int i, const int j, const int k, Scalar* buf[NUM_VTXBUF_HANDLES],
const int3 handle)
{
VectorData data;
data.xdata = read_scal_data(i, j, k, buf, handle.x);
data.ydata = read_scal_data(i, j, k, buf, handle.y);
data.zdata = read_scal_data(i, j, k, buf, handle.z);
return data;
}
static inline Scalar
value(const ScalarData data)
{
return data.value;
}
static inline Vector
gradient(const ScalarData data)
{
return data.gradient;
}
static inline Matrix
hessian(const ScalarData data)
{
return data.hessian;
}
static inline Vector
vecvalue(const VectorData data)
{
return (Vector){value(data.xdata), value(data.ydata), value(data.zdata)};
}
static inline Matrix
gradients(const VectorData data)
{
return (Matrix){
.row[0] = gradient(data.xdata),
.row[1] = gradient(data.ydata),
.row[2] = gradient(data.zdata),
};
}
/*
* =============================================================================
* Level 0.3 (Built-in functions available during the Stencil Processing Stage)
* =============================================================================
*/
/*
static inline Vector
operator-(const Vector a, const Vector b)
{
return (Vector){a[0] - b[0], a[1] - b[1], a[2] - b[2]};
}
static inline Vector
operator+(const Vector a, const Vector b)
{
return (Vector){a[0] + b[0], a[1] + b[1], a[2] + b[2]};
}
static inline Vector
operator-(const Vector a)
{
return (Vector){-a[0], -a[1], -a[2]};
}
static inline Vector operator*(const Scalar a, const Vector b)
{
return (Vector){a * b[0], a * b[1], a * b[2]};
}
*/
static inline Scalar
dot(const Vector a, const Vector b)
{
return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
}
static inline Vector
mul(const Matrix aa, const Vector x)
{
return (Vector){dot(aa.row[0], x), dot(aa.row[1], x), dot(aa.row[2], x)};
}
static inline Vector
cross(const Vector a, const Vector b)
{
Vector c;
c[0] = a[1] * b[2] - a[2] * b[1];
c[1] = a[2] * b[0] - a[0] * b[2];
c[2] = a[0] * b[1] - a[1] * b[0];
return c;
}
/*
static inline bool
is_valid(const Scalar a)
{
return !isnan(a) && !isinf(a);
}
static inline bool
is_valid(const Vector a)
{
return is_valid(a[0]) && is_valid(a[1]) && is_valid(a[2]);
}
*/
/*
* =============================================================================
* Stencil Processing Stage (helper functions)
* =============================================================================
*/
static inline Scalar
laplace(const ScalarData data)
{
return hessian(data).row[0][0] + hessian(data).row[1][1] + hessian(data).row[2][2];
}
static inline Scalar
divergence(const VectorData vec)
{
return gradient(vec.xdata)[0] + gradient(vec.ydata)[1] + gradient(vec.zdata)[2];
}
static inline Vector
laplace_vec(const VectorData vec)
{
return (Vector){laplace(vec.xdata), laplace(vec.ydata), laplace(vec.zdata)};
}
static inline Vector
curl(const VectorData vec)
{
return (Vector){gradient(vec.zdata)[1] - gradient(vec.ydata)[2],
gradient(vec.xdata)[2] - gradient(vec.zdata)[0],
gradient(vec.ydata)[0] - gradient(vec.xdata)[1]};
}
static inline Vector
gradient_of_divergence(const VectorData vec)
{
return (Vector){
hessian(vec.xdata).row[0][0] + hessian(vec.ydata).row[0][1] + hessian(vec.zdata).row[0][2],
hessian(vec.xdata).row[1][0] + hessian(vec.ydata).row[1][1] + hessian(vec.zdata).row[1][2],
hessian(vec.xdata).row[2][0] + hessian(vec.ydata).row[2][1] + hessian(vec.zdata).row[2][2]};
}
// Takes uu gradients and returns S
static inline Matrix
stress_tensor(const VectorData vec)
{
Matrix S;
S.row[0][0] = (Scalar)(2. / 3.) * gradient(vec.xdata)[0] -
(Scalar)(1. / 3.) * (gradient(vec.ydata)[1] + gradient(vec.zdata)[2]);
S.row[0][1] = (Scalar)(1. / 2.) * (gradient(vec.xdata)[1] + gradient(vec.ydata)[0]);
S.row[0][2] = (Scalar)(1. / 2.) * (gradient(vec.xdata)[2] + gradient(vec.zdata)[0]);
S.row[1][1] = (Scalar)(2. / 3.) * gradient(vec.ydata)[1] -
(Scalar)(1. / 3.) * (gradient(vec.xdata)[0] + gradient(vec.zdata)[2]);
S.row[1][2] = (Scalar)(1. / 2.) * (gradient(vec.ydata)[2] + gradient(vec.zdata)[1]);
S.row[2][2] = (Scalar)(2. / 3.) * gradient(vec.zdata)[2] -
(Scalar)(1. / 3.) * (gradient(vec.xdata)[0] + gradient(vec.ydata)[1]);
S.row[1][0] = S.row[0][1];
S.row[2][0] = S.row[0][2];
S.row[2][1] = S.row[1][2];
return S;
}
static inline Scalar
contract(const Matrix mat)
{
Scalar res = 0;
//#pragma unroll
for (int i = 0; i < 3; ++i)
res += dot(mat.row[i], mat.row[i]);
return res;
}
/*
* =============================================================================
* Stencil Processing Stage (equations)
* =============================================================================
*/
#if LUPWD
Scalar
upwd_der6(const VectorData uu, const ScalarData lnrho)
{
Scalar uux = fabs(vecvalue(uu)[0]);
Scalar uuy = fabs(vecvalue(uu)[1]);
Scalar uuz = fabs(vecvalue(uu)[2]);
return uux * lnrho.upwind[0] + uuy * lnrho.upwind[1] + uuz * lnrho.upwind[2];
}
#endif
static inline Scalar
continuity(const VectorData uu, const ScalarData lnrho)
{
return -dot(vecvalue(uu), gradient(lnrho))
#if LUPWD
// This is a corrective hyperdiffusion term for upwinding.
+ upwd_der6(uu, lnrho)
#endif
- divergence(uu);
}
static inline Scalar
length(const Vector vec)
{
return sqrt(vec[0] * vec[0] + vec[1] * vec[1] + vec[2] * vec[2]);
}
static inline Scalar
reciprocal_len(const Vector vec)
{
return (Scalar)(1.0) / sqrt(vec[0] * vec[0] + vec[1] * vec[1] + vec[2] * vec[2]);
}
static inline Vector
normalized(const Vector vec)
{
const Scalar inv_len = reciprocal_len(vec);
return inv_len * vec;
}
#define H_CONST ((Scalar)(0.0))
#define C_CONST ((Scalar)(0.0))
static inline Vector
momentum(const VectorData uu, const ScalarData lnrho
#if LENTROPY
,
const ScalarData ss, const VectorData aa
#endif
)
{
#if LENTROPY
const Matrix S = stress_tensor(uu);
const Scalar cs2 = getReal(AC_cs2_sound) *
exp(getReal(AC_gamma) * value(ss) / getReal(AC_cp_sound) +
(getReal(AC_gamma) - 1) * (value(lnrho) - getReal(AC_lnrho0)));
const Vector j = ((Scalar)(1.) / getReal(AC_mu0)) *
(gradient_of_divergence(aa) - laplace_vec(aa)); // Current density
const Vector B = curl(aa);
const Scalar inv_rho = (Scalar)(1.) / exp(value(lnrho));
const Vector mom = -mul(gradients(uu), vecvalue(uu)) -
cs2 * (((Scalar)(1.) / getReal(AC_cp_sound)) * gradient(ss) +
gradient(lnrho)) +
inv_rho * cross(j, B) +
getReal(AC_nu_visc) *
(laplace_vec(uu) + (Scalar)(1. / 3.) * gradient_of_divergence(uu) +
(Scalar)(2.) * mul(S, gradient(lnrho))) +
getReal(AC_zeta) * gradient_of_divergence(uu);
return mom;
#else
// !!!!!!!!!!!!!!!!%JP: NOTE TODO IMPORTANT!!!!!!!!!!!!!!!!!!!!!!!!
// NOT CHECKED FOR CORRECTNESS: USE AT YOUR OWN RISK
const Matrix S = stress_tensor(uu);
const Vector mom = -mul(gradients(uu), vecvalue(uu)) - getReal(AC_cs2_sound) * gradient(lnrho) +
getReal(AC_nu_visc) *
(laplace_vec(uu) + (Scalar)(1. / 3.) * gradient_of_divergence(uu) +
(Scalar)(2.) * mul(S, gradient(lnrho))) +
getReal(AC_zeta) * gradient_of_divergence(uu);
return mom;
#endif
}
static inline Vector
induction(const VectorData uu, const VectorData aa)
{
Vector ind;
// Note: We do (-nabla^2 A + nabla(nabla dot A)) instead of (nabla x (nabla
// x A)) in order to avoid taking the first derivative twice (did the math,
// yes this actually works. See pg.28 in arXiv:astro-ph/0109497)
// u cross B - ETA * mu0 * (mu0^-1 * [- laplace A + grad div A ])
const Vector B = curl(aa);
const Vector grad_div = gradient_of_divergence(aa);
const Vector lap = laplace_vec(aa);
// Note, mu0 is cancelled out
ind = cross(vecvalue(uu), B) - getReal(AC_eta) * (grad_div - lap);
return ind;
}
static inline Scalar
lnT(const ScalarData ss, const ScalarData lnrho)
{
const Scalar lnT = getReal(AC_lnT0) + getReal(AC_gamma) * value(ss) / getReal(AC_cp_sound) +
(getReal(AC_gamma) - (Scalar)(1.)) * (value(lnrho) - getReal(AC_lnrho0));
return lnT;
}
// Nabla dot (K nabla T) / (rho T)
static inline Scalar
heat_conduction(const ScalarData ss, const ScalarData lnrho)
{
const Scalar inv_cp_sound = (Scalar)(1.) / getReal(AC_cp_sound);
const Vector grad_ln_chi = -gradient(lnrho);
const Scalar first_term = getReal(AC_gamma) * inv_cp_sound * laplace(ss) +
(getReal(AC_gamma) - (Scalar)(1.)) * laplace(lnrho);
const Vector second_term = getReal(AC_gamma) * inv_cp_sound * gradient(ss) +
(getReal(AC_gamma) - (Scalar)(1.)) * gradient(lnrho);
const Vector third_term = getReal(AC_gamma) * (inv_cp_sound * gradient(ss) + gradient(lnrho)) +
grad_ln_chi;
const Scalar chi = AC_THERMAL_CONDUCTIVITY / (exp(value(lnrho)) * getReal(AC_cp_sound));
return getReal(AC_cp_sound) * chi * (first_term + dot(second_term, third_term));
}
static inline Scalar
entropy(const ScalarData ss, const VectorData uu, const ScalarData lnrho, const VectorData aa)
{
const Matrix S = stress_tensor(uu);
const Scalar inv_pT = (Scalar)(1.) / (exp(value(lnrho)) * exp(lnT(ss, lnrho)));
const Vector j = ((Scalar)(1.) / getReal(AC_mu0)) *
(gradient_of_divergence(aa) - laplace_vec(aa)); // Current density
const Scalar RHS = H_CONST - C_CONST + getReal(AC_eta) * getReal(AC_mu0) * dot(j, j) +
(Scalar)(2.) * exp(value(lnrho)) * getReal(AC_nu_visc) * contract(S) +
getReal(AC_zeta) * exp(value(lnrho)) * divergence(uu) * divergence(uu);
return -dot(vecvalue(uu), gradient(ss)) + inv_pT * RHS + heat_conduction(ss, lnrho);
/*
const Matrix S = stress_tensor(uu);
// nabla x nabla x A / mu0 = nabla(nabla dot A) - nabla^2(A)
const Vector j = gradient_of_divergence(aa) - laplace_vec(aa);
const Scalar inv_pT = (Scalar)(1.) / (exp(value(lnrho)) + exp(lnT(ss, lnrho)));
return - dot(vecvalue(uu), gradient(ss))
+ inv_pT * ( H_CONST - C_CONST
+ getReal(AC_eta) * getReal(AC_mu0) * dot(j, j)
+ (Scalar)(2.) * exp(value(lnrho)) * getReal(AC_nu_visc) * contract(S)
+ getReal(AC_zeta) * exp(value(lnrho)) * divergence(uu) * divergence(uu)
)
+ heat_conduction(ss, lnrho);
*/
}
static inline bool
is_valid(const Scalar a)
{
return !isnan(a) && !isinf(a);
}
static inline bool
is_valid_vec(const Vector a)
{
return is_valid(a[0]) && is_valid(a[1]) && is_valid(a[2]);
}
#if LFORCING
Vector
simple_vortex_forcing(Vector a, Vector b, Scalar magnitude)
{
return magnitude * cross(normalized(b - a), (Vector){0, 0, 1}); // Vortex
}
Vector
simple_outward_flow_forcing(Vector a, Vector b, Scalar magnitude)
{
return magnitude * (1 / length(b - a)) * normalized(b - a); // Outward flow
}
// The Pencil Code forcing_hel_noshear(), manual Eq. 222, inspired forcing function with adjustable
// helicity
Vector
helical_forcing(Scalar magnitude, Vector k_force, Vector xx, Vector ff_re, Vector ff_im, Scalar phi)
{
(void)magnitude; // WARNING: unused
xx[0] = xx[0] * (2.0 * M_PI / (getReal(AC_dsx) * getInt(AC_nx)));
xx[1] = xx[1] * (2.0 * M_PI / (getReal(AC_dsy) * getInt(AC_ny)));
xx[2] = xx[2] * (2.0 * M_PI / (getReal(AC_dsz) * getInt(AC_nz)));
Scalar cos_phi = cos(phi);
Scalar sin_phi = sin(phi);
Scalar cos_k_dot_x = cos(dot(k_force, xx));
Scalar sin_k_dot_x = sin(dot(k_force, xx));
// Phase affect only the x-component
// Scalar real_comp = cos_k_dot_x;
// Scalar imag_comp = sin_k_dot_x;
Scalar real_comp_phase = cos_k_dot_x * cos_phi - sin_k_dot_x * sin_phi;
Scalar imag_comp_phase = cos_k_dot_x * sin_phi + sin_k_dot_x * cos_phi;
Vector force = (Vector){ff_re[0] * real_comp_phase - ff_im[0] * imag_comp_phase,
ff_re[1] * real_comp_phase - ff_im[1] * imag_comp_phase,
ff_re[2] * real_comp_phase - ff_im[2] * imag_comp_phase};
return force;
}
Vector
forcing(int3 globalVertexIdx, Scalar dt)
{
Vector a = (Scalar)(.5) * (Vector){getInt(AC_nx) * getReal(AC_dsx),
getInt(AC_ny) * getReal(AC_dsy),
getInt(AC_nz) * getReal(AC_dsz)}; // source (origin)
(void)a; // WARNING: not used
Vector xx = (Vector){(globalVertexIdx.x - getInt(AC_nx_min)) * getReal(AC_dsx),
(globalVertexIdx.y - getInt(AC_ny_min)) * getReal(AC_dsy),
(globalVertexIdx.z - getInt(AC_nz_min)) *
getReal(AC_dsz)}; // sink (current index)
const Scalar cs2 = getReal(AC_cs2_sound);
const Scalar cs = sqrt(cs2);
// Placeholders until determined properly
Scalar magnitude = getReal(AC_forcing_magnitude);
Scalar phase = getReal(AC_forcing_phase);
Vector k_force = (Vector){getReal(AC_k_forcex), getReal(AC_k_forcey), getReal(AC_k_forcez)};
Vector ff_re = (Vector){getReal(AC_ff_hel_rex), getReal(AC_ff_hel_rey), getReal(AC_ff_hel_rez)};
Vector ff_im = (Vector){getReal(AC_ff_hel_imx), getReal(AC_ff_hel_imy), getReal(AC_ff_hel_imz)};
(void)phase; // WARNING: unused with simple forcing. Should be defined in helical_forcing
(void)k_force; // WARNING: unused with simple forcing. Should be defined in helical_forcing
(void)ff_re; // WARNING: unused with simple forcing. Should be defined in helical_forcing
(void)ff_im; // WARNING: unused with simple forcing. Should be defined in helical_forcing
// Determine that forcing funtion type at this point.
// Vector force = simple_vortex_forcing(a, xx, magnitude);
// Vector force = simple_outward_flow_forcing(a, xx, magnitude);
Vector force = helical_forcing(magnitude, k_force, xx, ff_re, ff_im, phase);
// Scaling N = magnitude*cs*sqrt(k*cs/dt) * dt
const Scalar NN = cs * sqrt(getReal(AC_kaver) * cs);
// MV: Like in the Pencil Code. I don't understandf the logic here.
force[0] = sqrt(dt) * NN * force[0];
force[1] = sqrt(dt) * NN * force[1];
force[2] = sqrt(dt) * NN * force[2];
if (is_valid_vec(force)) {
return force;
}
else {
return (Vector){0, 0, 0};
}
}
#endif
static void
solve_alpha_step(AcMesh in, const int step_number, const Scalar dt, const int i, const int j,
const int k, AcMesh* out)
{
const int idx = acVertexBufferIdx(i, j, k, in.info);
const ScalarData lnrho = read_scal_data(i, j, k, in.vertex_buffer, VTXBUF_LNRHO);
const VectorData uu = read_vec_data(i, j, k, in.vertex_buffer,
(int3){VTXBUF_UUX, VTXBUF_UUY, VTXBUF_UUZ});
Scalar rate_of_change[NUM_VTXBUF_HANDLES] = {0};
rate_of_change[VTXBUF_LNRHO] = continuity(uu, lnrho);
#if LMAGNETIC
const VectorData aa = read_vec_data(i, j, k, in.vertex_buffer,
(int3){VTXBUF_AX, VTXBUF_AY, VTXBUF_AZ});
const Vector aa_res = induction(uu, aa);
rate_of_change[VTXBUF_AX] = aa_res[0];
rate_of_change[VTXBUF_AY] = aa_res[1];
rate_of_change[VTXBUF_AZ] = aa_res[2];
#endif
#if LENTROPY
const ScalarData ss = read_scal_data(i, j, k, in.vertex_buffer, VTXBUF_ENTROPY);
const Vector uu_res = momentum(uu, lnrho, ss, aa);
rate_of_change[VTXBUF_UUX] = uu_res[0];
rate_of_change[VTXBUF_UUY] = uu_res[1];
rate_of_change[VTXBUF_UUZ] = uu_res[2];
rate_of_change[VTXBUF_ENTROPY] = entropy(ss, uu, lnrho, aa);
#else
const Vector uu_res = momentum(uu, lnrho);
rate_of_change[VTXBUF_UUX] = uu_res[0];
rate_of_change[VTXBUF_UUY] = uu_res[1];
rate_of_change[VTXBUF_UUZ] = uu_res[2];
#endif
// Williamson (1980) NOTE: older version of astaroth used inhomogenous
const Scalar alpha[] = {(Scalar)(.0), (Scalar)(-5. / 9.), (Scalar)(-153. / 128.)};
for (int w = 0; w < NUM_VTXBUF_HANDLES; ++w) {
if (step_number == 0) {
out->vertex_buffer[w][idx] = rate_of_change[w] * dt;
}
else {
out->vertex_buffer[w][idx] = alpha[step_number] * out->vertex_buffer[w][idx] +
rate_of_change[w] * dt;
}
}
}
static void
solve_beta_step(const AcMesh in, const int step_number, const Scalar dt, const int i, const int j,
const int k, AcMesh* out)
{
const int idx = acVertexBufferIdx(i, j, k, in.info);
// Williamson (1980) NOTE: older version of astaroth used inhomogenous
const Scalar beta[] = {(Scalar)(1. / 3.), (Scalar)(15. / 16.), (Scalar)(8. / 15.)};
for (int w = 0; w < NUM_VTXBUF_HANDLES; ++w)
out->vertex_buffer[w][idx] += beta[step_number] * in.vertex_buffer[w][idx];
(void)dt; // Suppress unused variable warning if forcing not used
#if LFORCING
if (step_number == 2) {
Vector force = forcing((int3){i, j, k}, dt);
out->vertex_buffer[VTXBUF_UUX][idx] += force[0];
out->vertex_buffer[VTXBUF_UUY][idx] += force[1];
out->vertex_buffer[VTXBUF_UUZ][idx] += force[2];
}
#endif
}
// Checks whether the parameters passed in an AcMeshInfo are valid
static void
checkConfiguration(const AcMeshInfo info)
{
for (int i = 0; i < NUM_REAL_PARAMS; ++i) {
if (!is_valid(info.real_params[i])) {
fprintf(stderr, "WARNING: Passed an invalid value %g to model solver (%s). Skipping.\n",
(double)info.real_params[i], realparam_names[i]);
}
}
for (int i = 0; i < NUM_REAL3_PARAMS; ++i) {
if (!is_valid(info.real3_params[i].x)) {
fprintf(stderr,
"WARNING: Passed an invalid value %g to model solver (%s.x). Skipping.\n",
(double)info.real3_params[i].x, realparam_names[i]);
}
if (!is_valid(info.real3_params[i].y)) {
fprintf(stderr,
"WARNING: Passed an invalid value %g to model solver (%s.y). Skipping.\n",
(double)info.real3_params[i].y, realparam_names[i]);
}
if (!is_valid(info.real3_params[i].z)) {
fprintf(stderr,
"WARNING: Passed an invalid value %g to model solver (%s.z). Skipping.\n",
(double)info.real3_params[i].z, realparam_names[i]);
}
}
ERRCHK_ALWAYS(is_valid(info.real_params[AC_inv_dsx]));
ERRCHK_ALWAYS(is_valid(info.real_params[AC_inv_dsy]));
ERRCHK_ALWAYS(is_valid(info.real_params[AC_inv_dsz]));
ERRCHK_ALWAYS(is_valid(info.real_params[AC_cs2_sound]));
}
AcResult
acModelIntegrateStep(AcMesh mesh, const AcReal dt)
{
mesh_info = &(mesh.info);
// Setup built-in parameters
mesh_info->real_params[AC_inv_dsx] = (AcReal)(1.0) / mesh_info->real_params[AC_dsx];
mesh_info->real_params[AC_inv_dsy] = (AcReal)(1.0) / mesh_info->real_params[AC_dsy];
mesh_info->real_params[AC_inv_dsz] = (AcReal)(1.0) / mesh_info->real_params[AC_dsz];
mesh_info->real_params[AC_cs2_sound] = mesh_info->real_params[AC_cs_sound] *
mesh_info->real_params[AC_cs_sound];
checkConfiguration(*mesh_info);
AcMesh intermediate_mesh;
acMeshCreate(mesh.info, &intermediate_mesh);
const int nx_min = getInt(AC_nx_min);
const int nx_max = getInt(AC_nx_max);
const int ny_min = getInt(AC_ny_min);
const int ny_max = getInt(AC_ny_max);
const int nz_min = getInt(AC_nz_min);
const int nz_max = getInt(AC_nz_max);
for (int step_number = 0; step_number < 3; ++step_number) {
// Boundconds
acMeshApplyPeriodicBounds(&mesh);
// Alpha step
// #pragma omp parallel for
for (int k = nz_min; k < nz_max; ++k) {
for (int j = ny_min; j < ny_max; ++j) {
for (int i = nx_min; i < nx_max; ++i) {
solve_alpha_step(mesh, step_number, dt, i, j, k, &intermediate_mesh);
}
}
}
// Beta step
// #pragma omp parallel for
for (int k = nz_min; k < nz_max; ++k) {
for (int j = ny_min; j < ny_max; ++j) {
for (int i = nx_min; i < nx_max; ++i) {
solve_beta_step(intermediate_mesh, step_number, dt, i, j, k, &mesh);
}
}
}
}
acMeshDestroy(&intermediate_mesh);
mesh_info = NULL;
return AC_SUCCESS;
}