From eb52e10dc48c3066cf0e3e8931917f72e7b0b5f4 Mon Sep 17 00:00:00 2001
From: Martin Bauer <martin.bauer@fau.de>
Date: Tue, 10 Apr 2018 17:41:35 +0200
Subject: [PATCH] Tests for derivative & Chapman Enskog
---
derivative.py | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/derivative.py b/derivative.py
index 2dbcae451..3135761f7 100644
--- a/derivative.py
+++ b/derivative.py
@@ -195,10 +195,10 @@ def collect_derivatives(expr):
return expr.collect(derivative_terms(expr))
-def create_nested_diff(*args, arg=None):
+def create_nested_diff(arg, *args):
"""Shortcut to create nested derivatives"""
assert arg is not None
- args = sorted(args, reverse=True)
+ args = sorted(args, reverse=True, key=lambda e: e.name if isinstance(e, sp.Symbol) else e)
res = arg
for i in args:
res = Diff(res, i)
@@ -455,7 +455,7 @@ def functional_derivative(functional, v):
\frac{\delta F}{\delta v} =
\frac{\partial F}{\partial v} - \nabla \cdot \frac{\partial F}{\partial \nabla v}
- - assumes that gradients are represented by Diff() node (from Chapman Enskog module)
+ - assumes that gradients are represented by Diff() node
- Diff(Diff(r)) represents the divergence of r
- the constants parameter is a list with symbols not affected by the derivative. This is used for simplification
of the derivative terms.
--
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