From 7ee1ca337f25ab6ead86ead28c10df520cff1b63 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Tue, 2 Jul 2019 14:58:36 +0200
Subject: Determine weights using Gauss-Hermite quadrature

---
 symbolic/generator.py | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

(limited to 'symbolic/generator.py')

diff --git a/symbolic/generator.py b/symbolic/generator.py
index f94031f..73f3940 100644
--- a/symbolic/generator.py
+++ b/symbolic/generator.py
@@ -2,6 +2,7 @@ from sympy import *
 from sympy.codegen.ast import Assignment
 
 import symbolic.optimizations as optimizations
+from symbolic.characteristics import weights
 
 
 def assign(names, definitions):
@@ -13,6 +14,11 @@ class LBM:
         self.f_next = symarray('f_next', descriptor.q)
         self.f_curr = symarray('f_curr', descriptor.q)
 
+        if hasattr(descriptor, 'w'):
+            self.w = descriptor.w
+        else:
+            self.w = weights(descriptor.d, descriptor.c)
+
     def moments(self, optimize = True):
         rho = symbols('rho')
         u   = Matrix(symarray('u', self.descriptor.d))
@@ -35,10 +41,10 @@ class LBM:
         f_eq = []
 
         for i, c_i in enumerate(self.descriptor.c):
-            f_eq_i = self.descriptor.w[i] * rho * ( 1
-                                                  + c_i.dot(u)    /    self.descriptor.c_s**2
-                                                  + c_i.dot(u)**2 / (2*self.descriptor.c_s**4)
-                                                  - u.dot(u)      / (2*self.descriptor.c_s**2) )
+            f_eq_i = self.w[i] * rho * ( 1
+                                       + c_i.dot(u)    /    self.descriptor.c_s**2
+                                       + c_i.dot(u)**2 / (2*self.descriptor.c_s**4)
+                                       - u.dot(u)      / (2*self.descriptor.c_s**2) )
             f_eq.append(f_eq_i)
 
         return f_eq
-- 
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