From bed12f7527a1813beccc06a897107f693ed06325 Mon Sep 17 00:00:00 2001
From: Martin Bauer <martin.bauer@fau.de>
Date: Fri, 20 Jan 2017 13:52:56 +0100
Subject: [PATCH] pystencils: generalized equationcollection
---
equationcollection/equationcollection.py | 127 +++++++++++++----------
equationcollection/simplifications.py | 19 ++--
sympyextensions.py | 6 +-
3 files changed, 83 insertions(+), 69 deletions(-)
diff --git a/equationcollection/equationcollection.py b/equationcollection/equationcollection.py
index 8c6c6f32f..2ea0c2b6f 100644
--- a/equationcollection/equationcollection.py
+++ b/equationcollection/equationcollection.py
@@ -1,4 +1,5 @@
import sympy as sp
+from copy import copy, deepcopy
from pystencils.sympyextensions import fastSubs, countNumberOfOperations
@@ -20,52 +21,50 @@ class EquationCollection:
# ----------------------------------------- Creation ---------------------------------------------------------------
- def __init__(self, equations, subExpressions, simplificationHints={}, subexpressionSymbolNameGenerator=None):
+ def __init__(self, equations, subExpressions, simplificationHints=None, subexpressionSymbolNameGenerator=None):
self.mainEquations = equations
self.subexpressions = subExpressions
+
+ if simplificationHints is None:
+ simplificationHints = {}
+
self.simplificationHints = simplificationHints
- def symbolGen():
- """Use this generator to create new unused symbols for subexpressions"""
- counter = 0
- while True:
- counter += 1
- newSymbol = sp.Symbol("xi_" + str(counter))
- if newSymbol in self.boundSymbols:
- continue
- yield newSymbol
+ class SymbolGen:
+ def __init__(self):
+ self._ctr = 0
+
+ def __iter__(self):
+ return self
+
+ def __next__(self):
+ self._ctr += 1
+ return sp.Symbol("xi_" + str(self._ctr))
if subexpressionSymbolNameGenerator is None:
- self.subexpressionSymbolNameGenerator = symbolGen()
+ self.subexpressionSymbolNameGenerator = SymbolGen()
else:
self.subexpressionSymbolNameGenerator = subexpressionSymbolNameGenerator
- def newWithAdditionalSubexpressions(self, newEquations, additionalSubExpressions):
- """
- Returns a new equation collection, that has `newEquations` as mainEquations.
- The `additionalSubExpressions` are appended to the existing subexpressions.
- Simplifications hints are copied over.
- """
- assert len(self.mainEquations) == len(newEquations), "Number of update equations cannot be changed"
- res = EquationCollection(newEquations,
- self.subexpressions + additionalSubExpressions,
- self.simplificationHints)
- res.subexpressionSymbolNameGenerator = self.subexpressionSymbolNameGenerator
+ def copy(self, mainEquations=None, subexpressions=None):
+ res = deepcopy(self)
+ if mainEquations is not None:
+ res.mainEquations = mainEquations
+ if subexpressions is not None:
+ res.subexpressions = subexpressions
return res
- def newWithSubstitutionsApplied(self, substitutionDict, addSubstitutionsAsSubexpresions=False):
+ def copyWithSubstitutionsApplied(self, substitutionDict, addSubstitutionsAsSubexpressions=False):
"""
Returns a new equation collection, where terms are substituted according to the passed `substitutionDict`.
Substitutions are made in the subexpression terms and the main equations
"""
newSubexpressions = [fastSubs(eq, substitutionDict) for eq in self.subexpressions]
newEquations = [fastSubs(eq, substitutionDict) for eq in self.mainEquations]
- if addSubstitutionsAsSubexpresions:
+ if addSubstitutionsAsSubexpressions:
newSubexpressions = [sp.Eq(b, a) for a, b in substitutionDict.items()] + newSubexpressions
- res = EquationCollection(newEquations, newSubexpressions, self.simplificationHints)
- res.subexpressionSymbolNameGenerator = self.subexpressionSymbolNameGenerator
- return res
+ return self.copy(newEquations, newSubexpressions)
def addSimplificationHint(self, key, value):
"""
@@ -178,41 +177,45 @@ class EquationCollection:
substitutionDict[otherSubexpressionEq.lhs] = newLhs
else:
processedOtherSubexpressionEquations.append(fastSubs(otherSubexpressionEq, substitutionDict))
- return EquationCollection(self.mainEquations + other.mainEquations,
- self.subexpressions + processedOtherSubexpressionEquations)
+ return self.copy(self.mainEquations + other.mainEquations,
+ self.subexpressions + processedOtherSubexpressionEquations)
- def extract(self, symbolsToExtract):
- """
- Creates a new equation collection with equations that have symbolsToExtract as left-hand-sides and
- only the necessary subexpressions that are used in these equations
- """
- symbolsToExtract = set(symbolsToExtract)
- newEquations = []
+ def getDependentSymbols(self, symbolSequence):
+ """Returns a list of symbols that depend on the passed symbols."""
- subexprMap = {e.lhs: e.rhs for e in self.subexpressions}
- handledSymbols = set()
- queue = []
+ queue = list(symbolSequence)
def addSymbolsFromExpr(expr):
dependentSymbols = expr.atoms(sp.Symbol)
for ds in dependentSymbols:
- if ds not in handledSymbols:
- queue.append(ds)
- handledSymbols.add(ds)
+ queue.append(ds)
- for eq in self.allEquations:
- if eq.lhs in symbolsToExtract:
- newEquations.append(eq)
- addSymbolsFromExpr(eq.rhs)
+ handledSymbols = set()
+ eqMap = {e.lhs: e.rhs for e in self.allEquations}
while len(queue) > 0:
e = queue.pop(0)
- if e not in subexprMap:
+ if e in handledSymbols:
continue
- else:
- addSymbolsFromExpr(subexprMap[e])
+ if e in eqMap:
+ addSymbolsFromExpr(eqMap[e])
+ handledSymbols.add(e)
+
+ return handledSymbols
+
+ def extract(self, symbolsToExtract):
+ """
+ Creates a new equation collection with equations that have symbolsToExtract as left-hand-sides and
+ only the necessary subexpressions that are used in these equations
+ """
+ symbolsToExtract = set(symbolsToExtract)
+ dependentSymbols = self.getDependentSymbols(symbolsToExtract)
+ newEquations = []
+ for eq in self.allEquations:
+ if eq.lhs in symbolsToExtract:
+ newEquations.append(eq)
- newSubExpr = [eq for eq in self.subexpressions if eq.lhs in handledSymbols and eq.lhs not in symbolsToExtract]
+ newSubExpr = [eq for eq in self.subexpressions if eq.lhs in dependentSymbols and eq.lhs not in symbolsToExtract]
return EquationCollection(newEquations, newSubExpr)
def newWithoutUnusedSubexpressions(self):
@@ -221,18 +224,30 @@ class EquationCollection:
allLhs = [eq.lhs for eq in self.mainEquations]
return self.extract(allLhs)
- def insertSubexpressions(self):
+ def insertSubexpressions(self, subexpressionSymbolsToKeep=set()):
"""Returns a new equation collection by inserting all subexpressions into the main equations"""
if len(self.subexpressions) == 0:
- return EquationCollection(self.mainEquations, self.subexpressions, self.simplificationHints)
- subsDict = {self.subexpressions[0].lhs: self.subexpressions[0].rhs}
+ return self.copy()
+
+ subexpressionSymbolsToKeep = set(subexpressionSymbolsToKeep)
+
+ keptSubexpressions = []
+ if self.subexpressions[0].lhs in subexpressionSymbolsToKeep:
+ subsDict = {}
+ keptSubexpressions = self.subexpressions[0]
+ else:
+ subsDict = {self.subexpressions[0].lhs: self.subexpressions[0].rhs}
+
subExpr = [e for e in self.subexpressions]
for i in range(1, len(subExpr)):
subExpr[i] = fastSubs(subExpr[i], subsDict)
- subsDict[subExpr[i].lhs] = subExpr[i].rhs
+ if subExpr[i].lhs in subexpressionSymbolsToKeep:
+ keptSubexpressions.append(subExpr[i])
+ else:
+ subsDict[subExpr[i].lhs] = subExpr[i].rhs
newEq = [fastSubs(eq, subsDict) for eq in self.mainEquations]
- return EquationCollection(newEq, [], self.simplificationHints)
+ return self.copy(newEq, keptSubexpressions)
def lambdify(self, symbols, module=None, fixedSymbols={}):
"""
@@ -241,7 +256,7 @@ class EquationCollection:
:param module: same as sympy.lambdify paramter of same same, i.e. which module to use e.g. 'numpy'
:param fixedSymbols: dictionary with substitutions, that are applied before lambdification
"""
- eqs = self.newWithSubstitutionsApplied(fixedSymbols).insertSubexpressions().mainEquations
+ eqs = self.copyWithSubstitutionsApplied(fixedSymbols).insertSubexpressions().mainEquations
lambdas = {eq.lhs: sp.lambdify(symbols, eq.rhs, module) for eq in eqs}
def f(*args, **kwargs):
diff --git a/equationcollection/simplifications.py b/equationcollection/simplifications.py
index 412a889cc..328373599 100644
--- a/equationcollection/simplifications.py
+++ b/equationcollection/simplifications.py
@@ -1,5 +1,4 @@
import sympy as sp
-from pystencils.equationcollection import EquationCollection
from pystencils.sympyextensions import replaceAdditive
@@ -21,21 +20,18 @@ def sympyCSE(equationCollection):
topologicallySortedPairs = sp.cse_main.reps_toposort([[e.lhs, e.rhs] for e in newSubexpressions])
newSubexpressions = [sp.Eq(a[0], a[1]) for a in topologicallySortedPairs]
- return EquationCollection(modifiedUpdateEquations, newSubexpressions, equationCollection.simplificationHints,
- equationCollection.subexpressionSymbolNameGenerator)
+ return equationCollection.copy(modifiedUpdateEquations, newSubexpressions)
def applyOnAllEquations(equationCollection, operation):
"""Applies sympy expand operation to all equations in collection"""
result = [operation(s) for s in equationCollection.mainEquations]
- return equationCollection.newWithAdditionalSubexpressions(result, [])
+ return equationCollection.copy(result)
def applyOnAllSubexpressions(equationCollection, operation):
- return EquationCollection(equationCollection.mainEquations,
- [operation(s) for s in equationCollection.subexpressions],
- equationCollection.simplificationHints,
- equationCollection.subexpressionSymbolNameGenerator)
+ return equationCollection.copy(equationCollection.mainEquations,
+ [operation(s) for s in equationCollection.subexpressions])
def subexpressionSubstitutionInExistingSubexpressions(equationCollection):
@@ -49,8 +45,7 @@ def subexpressionSubstitutionInExistingSubexpressions(equationCollection):
newRhs = newRhs.subs(subExpr.rhs, subExpr.lhs)
result.append(sp.Eq(s.lhs, newRhs))
- return EquationCollection(equationCollection.mainEquations, result, equationCollection.simplificationHints,
- equationCollection.subexpressionSymbolNameGenerator)
+ return equationCollection.copy(equationCollection.mainEquations, result)
def subexpressionSubstitutionInMainEquations(equationCollection):
@@ -61,7 +56,7 @@ def subexpressionSubstitutionInMainEquations(equationCollection):
for subExpr in equationCollection.subexpressions:
newRhs = replaceAdditive(newRhs, subExpr.lhs, subExpr.rhs, requiredMatchReplacement=1.0)
result.append(sp.Eq(s.lhs, newRhs))
- return equationCollection.newWithAdditionalSubexpressions(result, [])
+ return equationCollection.copy(result)
def addSubexpressionsForDivisions(equationCollection):
@@ -80,4 +75,4 @@ def addSubexpressionsForDivisions(equationCollection):
newSymbolGen = equationCollection.subexpressionSymbolNameGenerator
substitutions = {divisor: newSymbol for newSymbol, divisor in zip(newSymbolGen, divisors)}
- return equationCollection.newWithSubstitutionsApplied(substitutions, True)
+ return equationCollection.copyWithSubstitutionsApplied(substitutions, True)
diff --git a/sympyextensions.py b/sympyextensions.py
index e02b58be9..8daa67136 100644
--- a/sympyextensions.py
+++ b/sympyextensions.py
@@ -14,7 +14,11 @@ def fastSubs(term, subsDict):
return expr
paramList = [visit(a) for a in expr.args]
return expr if not paramList else expr.func(*paramList)
- return visit(term)
+
+ if len(subsDict) == 0:
+ return term
+ else:
+ return visit(term)
def replaceAdditive(expr, replacement, subExpression, requiredMatchReplacement=0.5, requiredMatchOriginal=None):
--
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