Commit 87e72ed1 authored by itischler's avatar itischler
Browse files

Merge branch 'pressure_tensor' of https://i10git.cs.fau.de/itischler/lbmpy...

Merge branch 'pressure_tensor' of https://i10git.cs.fau.de/itischler/lbmpy into pressure_tensor_test
parents 69c89003 34272d9e
......@@ -84,13 +84,15 @@ class AbstractConservedQuantityComputation(abc.ABC):
class DensityVelocityComputation(AbstractConservedQuantityComputation):
def __init__(self, stencil, compressible, force_model=None,
zeroth_order_moment_symbol=sp.Symbol("rho"),
first_order_moment_symbols=sp.symbols("u_:3")):
first_order_moment_symbols=sp.symbols("u_:3"),
second_order_moment_symbols=sp.symbols("p_:9")):
dim = len(stencil[0])
self._stencil = stencil
self._compressible = compressible
self._forceModel = force_model
self._symbolOrder0 = zeroth_order_moment_symbol
self._symbolsOrder1 = first_order_moment_symbols[:dim]
self._symbolsOrder2 = second_order_moment_symbols[:(dim * dim)]
@property
def conserved_quantities(self):
......@@ -166,7 +168,8 @@ class DensityVelocityComputation(AbstractConservedQuantityComputation):
dim = len(self._stencil[0])
ac = get_equations_for_zeroth_and_first_order_moment(self._stencil, pdfs,
self._symbolOrder0, self._symbolsOrder1)
self._symbolOrder0, self._symbolsOrder1,
self._symbolsOrder2)
if self._compressible:
ac = divide_first_order_moments_by_rho(ac, dim)
......@@ -209,6 +212,7 @@ class DensityVelocityComputation(AbstractConservedQuantityComputation):
self._symbolsOrder1)
mom_density_eq_coll = apply_force_model_shift('macroscopic_momentum_density_shift', dim,
mom_density_eq_coll, self._forceModel, self._compressible)
for sym, val in zip(momentum_density_output_symbols, mom_density_eq_coll.main_assignments[1:]):
main_assignments.append(Assignment(sym, val.rhs))
if 'moment0' in output_quantity_names_to_symbols:
......@@ -222,6 +226,10 @@ class DensityVelocityComputation(AbstractConservedQuantityComputation):
moment1_output_symbol = moment1_output_symbol.center_vector
main_assignments.extend([Assignment(lhs, sum(d[i] * pdf for d, pdf in zip(self._stencil, pdfs)))
for i, lhs in enumerate(moment1_output_symbol)])
if 'moment2' in output_quantity_names_to_symbols:
for p_i in self._symbolsOrder2:
main_assignments.append(Assignment(p_i, eqs[p_i]))
del eqs[p_i]
ac = ac.copy(main_assignments, [Assignment(a, b) for a, b in eqs.items()])
return ac.new_without_unused_subexpressions()
......@@ -233,8 +241,8 @@ class DensityVelocityComputation(AbstractConservedQuantityComputation):
# ----------------------------------------- Helper functions ----------------------------------------------------------
def get_equations_for_zeroth_and_first_order_moment(stencil, symbolic_pdfs,
symbolic_zeroth_moment, symbolic_first_moments):
def get_equations_for_zeroth_and_first_order_moment(stencil, symbolic_pdfs, symbolic_zeroth_moment,
symbolic_first_moments, symbolic_second_moments=None):
r"""
Returns an equation system that computes the zeroth and first order moments with the least amount of operations
......@@ -244,12 +252,14 @@ def get_equations_for_zeroth_and_first_order_moment(stencil, symbolic_pdfs,
\rho = \sum_{d \in S} f_d
u_j = \sum_{d \in S} f_d u_jd
p_j = \sum_{d \in S} {d \in S} f_d u_jd
Args:
stencil: called :math:`S` above
symbolic_pdfs: called :math:`f` above
symbolic_zeroth_moment: called :math:`\rho` above
symbolic_first_moments: called :math:`u` above
symbolic_second_moments: called :math:`p` above
"""
def filter_out_plus_terms(expr):
result = 0
......@@ -267,6 +277,12 @@ def get_equations_for_zeroth_and_first_order_moment(stencil, symbolic_pdfs,
for i in range(dim):
u[i] += f * int(offset[i])
p = [0] * dim * dim
for f, offset in zip(symbolic_pdfs, stencil):
for i in range(dim):
for j in range(dim):
p[dim * i + j] += f * int(offset[i]) * int(offset[j])
plus_terms = [set(filter_out_plus_terms(u_i).args) for u_i in u]
for i in range(dim):
rhs = plus_terms[i]
......@@ -284,6 +300,8 @@ def get_equations_for_zeroth_and_first_order_moment(stencil, symbolic_pdfs,
equations = []
equations += [Assignment(symbolic_zeroth_moment, pdf_sum)]
equations += [Assignment(u_i_sym, u_i) for u_i_sym, u_i in zip(symbolic_first_moments, u)]
if symbolic_second_moments:
equations += [Assignment(symbolic_second_moments[i], p[i]) for i in range(dim**2)]
return AssignmentCollection(equations, subexpressions)
......
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