Changeset 615 for branches

Timestamp:

12/19/12 08:58:47 (3 years ago)

Author:

mmckerns

Message:

added more docstrings to _symbolic; convert == to = for sympy;
make sympy solve for 0.7.1 return all permutations like solve in 0.6.7;
_classify_variables returns variable names not indices

File:

• branches/decorate/_symbolic.py (modified) (13 diffs)

branches/decorate/_symbolic.py

@@ -19 +19 @@
         ...     x1 = x5**2
         ...     x3 = x4 + x5'''
-        >>> print _classify_variables(constraints, nvars=5)
-        {'dependent':[1, 3], 'independent':[4, 5], 'unconstrained':[2]}
+        >>> _classify_variables(constraints, nvars=5)
+        {'dependent':['x1','x3'], 'independent':['x4','x5'], 'unconstrained':['x2']}
         >>> constraints = '''
         ...     x1 = x5**2
@@ -26 +26 @@
         ...     x5 - x1 = x3'''
         >>> _classify_variables(constraints, nvars=5)
-        {'dependent': [1, 3, 5], 'independent': [4], 'unconstrained': [2]}
+        {'dependent': ['x1','x3','x5'], 'independent': ['x4'], 'unconstrained': ['x2']}
 
 Additional Inputs:
@@ -36 +36 @@
         found in the constraints equation string.
 """
-    #XXX: use simplify_symbolic first if not in form xi = ... ?
+    #XXX: use simplify_symbolic? or first if not in form xi = ... ?
     if list_or_tuple_or_ndarray(variables):
         if nvars: variables = variables[:nvars]
@@ -50 +50 @@
 
     eqns = constraints.splitlines()
-    variables = range(1, ndim+1)
+    indices = range(1, ndim+1)
     dep = []
     indep = []
@@ -56 +56 @@
         if eqn:
             for var in range(1, ndim+1):
-                if variables.count(var) != 0:
+                if indices.count(var) != 0:
                     if eqn.find(varname + str(var)) != -1:
                         indep.append(var)
-                        variables.remove(var)
+                        indices.remove(var)
     indep.sort()
     _dep = []
@@ -89 +89 @@
     ...     x3 - x5 - x4 = 0.'''
     >>> _classify_variables(constraints, nvars=5)
-    {'dependent': [1, 3], 'independent': [4, 5], 'unconstrained': [2]}
+    {'dependent': ['x1','x3'], 'independent': ['x4','x5'], 'unconstrained': ['x2']}
     >>> constraints = '''
     ...     x1 + x3 = 0.
     ...     x1 + 2*x3 = 0.'''
     >>> _classify_variables(constraints, nvars=5)
-    {'dependent': [1, 3], 'independent': [], 'unconstrained': [2, 4, 5]}
+    {'dependent': ['x1','x3'], 'independent': [], 'unconstrained': ['x2','x4','x5']}
 
     This is a bug:
@@ -101 +101 @@
     ...     2*x1 + 2*x3 = 0.'''
     >>> _classify_variables(constraints, nvars=5)
-    {'dependent': [1, 3], 'independent': [], 'unconstrained': [2, 4, 5]}
+    {'dependent': ['x1','x3'], 'independent': [], 'unconstrained': ['x2','x4','x5']}
     """ #XXX: should simplify first?
     dep.sort()
     indep.sort()
-    d = {'dependent':dep, 'independent':indep, 'unconstrained':variables}
+    # return the actual variable names (not the indicies)
+    if varname == variables: # then was single variable
+        variables = [varname+str(i) for i in range(1,ndim+1)]
+    dep = [variables[i-1] for i in dep]
+    indep = [variables[i-1] for i in indep]
+    indices = [variables[i-1] for i in indices]
+    d = {'dependent':dep, 'independent':indep, 'unconstrained':indices}
     return d
 
@@ -120 +126 @@
         Standard python syntax should be followed (with the math and numpy
         modules already imported).
+
+    For example:
+        >>> constraints = '''
+        ...     x1 = x5**2
+        ...     x5 - x4 = 0.
+        ...     x5 - x1 = x3'''
+        >>> code, lhs, rhs, vars, neqn = _prepare_sympy(constraints, nvars=5)
+        >>> print code
+        x1=Symbol('x1')
+        x2=Symbol('x2')
+        x3=Symbol('x3')
+        x4=Symbol('x4')
+        x5=Symbol('x5')
+        rand = Symbol('rand')
+        >>> print lhs, rhs
+        ['x1 ', 'x5 - x4 ', 'x5 - x1 '] [' x5**2', ' 0.', ' x3']
+        print "%s in %s eqns" % (vars, neqn)        
+        x1,x2,x3,x4,x5, in 3 eqns
 
 Additional Inputs:
@@ -148 +172 @@
     right = []
     for eq in eacheqn: #XXX: Le/Ge instead of Eq; Max/Min... (NotImplemented ?)
-        splitlist = eq.split('=') #FIXME: seems not to handle inequalities
+        splitlist = eq.replace('==','=').split('=') #FIXME: no inequalities
         if len(splitlist) == 2:   #FIXME: first convert >/< to min/max ?
 
@@ -186 +210 @@
 Inputs:
     constraint -- a string of symbolic constraints. Only a single constraint
-        equation should be providedi, and must be an equality constraint. 
+        equation should be provided, and must be an equality constraint. 
         Standard python syntax should be followed (with the math and numpy
         modules already imported).
@@ -209 +233 @@
         x2 = 3.0 + x1*x3
 """
+    # for now, we abort on multi-line equations or inequalities
+    if len(constraint.replace('==','=').split('=')) != 2:
+        raise NotImplementedError, "requires a single valid equation" 
+    if ">" in constraint or "<" in constraint:
+        raise NotImplementedError, "cannot simplify inequalities" 
+
     if list_or_tuple_or_ndarray(variables):
         if nvars: variables = variables[:nvars]
@@ -222 +252 @@
         if myvar: ndim = max([int(v.strip(varname)) for v in myvar])
         else: ndim = 0
-    '''Bug (?) demonstrated here:  [fails on inequality]
-    >>> constr = """
-      x1**2 = 2.5*x2 - 5.0
-      exp(x3/x1) >= 7.0"""
-    >>> simplify_symbolic(constr, target='x1')
-    'x1 = (-5.0 + 2.5*x2)**(1/2)'
-    >>> simplify_symbolic(constr, target='x2')
-    'x2 = 2.0 + 0.4*x1**2'
-    >>> simplify_symbolic(constr, target='x3')
-    Warning: target variable is not valid
-    >>> print simplify_symbolic(constr)
-    x2 = 2.0 + 0.4*x1**2
-    x1 = (-5.0 + 2.5*x2)**(1/2)
-    x1 = -(-5.0 + 2.5*x2)**(1/2)
-    '''
+
     warn = True  # if True, don't supress warning about old versions of sympy
     if kwds.has_key('warn'): warn = kwds['warn']
@@ -265 +281 @@
 
     if not target: #XXX: the goal is solving *only one* equation
-        code += 'soln = symsol(eq, [' + xlist + '])\n'
+       #code += 'soln = symsol(eq, [' + xlist + '])\n'
+        code += '_xlist = %s\n' % xlist
+        code += 'soln = {}\n'
+        code += '[soln.update({i:symsol(eq, i)}) for i in _xlist]\n'
     else:
         code += 'soln = symsol(eq, [' + target + '])\n'