Merge pull request #126 from ShikharJ/MinMax

Wrapped Min and Max Functions

Author: isuruf

symengine/lib/symengine.pxd

@@ -143,6 +143,8 @@ cdef extern from "<symengine/symengine_rcp.h>" namespace "SymEngine":
     RCP[const FunctionSymbol] rcp_static_cast_FunctionSymbol "SymEngine::rcp_static_cast<const SymEngine::FunctionSymbol>"(RCP[const Basic] &b) nogil
     RCP[const FunctionWrapper] rcp_static_cast_FunctionWrapper "SymEngine::rcp_static_cast<const SymEngine::FunctionWrapper>"(RCP[const Basic] &b) nogil
     RCP[const Abs] rcp_static_cast_Abs "SymEngine::rcp_static_cast<const SymEngine::Abs>"(RCP[const Basic] &b) nogil
+    RCP[const Max] rcp_static_cast_Max "SymEngine::rcp_static_cast<const SymEngine::Max>"(RCP[const Basic] &b) nogil
+    RCP[const Min] rcp_static_cast_Min "SymEngine::rcp_static_cast<const SymEngine::Min>"(RCP[const Basic] &b) nogil
     RCP[const Gamma] rcp_static_cast_Gamma "SymEngine::rcp_static_cast<const SymEngine::Gamma>"(RCP[const Basic] &b) nogil
     RCP[const Derivative] rcp_static_cast_Derivative "SymEngine::rcp_static_cast<const SymEngine::Derivative>"(RCP[const Basic] &b) nogil
     RCP[const Subs] rcp_static_cast_Subs "SymEngine::rcp_static_cast<const SymEngine::Subs>"(RCP[const Basic] &b) nogil
@@ -251,6 +253,8 @@ cdef extern from "<symengine/basic.h>" namespace "SymEngine":
     bool is_a_ASech "SymEngine::is_a<SymEngine::ASech>"(const Basic &b) nogil
     bool is_a_FunctionSymbol "SymEngine::is_a<SymEngine::FunctionSymbol>"(const Basic &b) nogil
     bool is_a_Abs "SymEngine::is_a<SymEngine::Abs>"(const Basic &b) nogil
+    bool is_a_Max "SymEngine::is_a<SymEngine::Max>"(const Basic &b) nogil
+    bool is_a_Min "SymEngine::is_a<SymEngine::Min>"(const Basic &b) nogil
     bool is_a_Gamma "SymEngine::is_a<SymEngine::Gamma>"(const Basic &b) nogil
     bool is_a_Derivative "SymEngine::is_a<SymEngine::Derivative>"(const Basic &b) nogil
     bool is_a_Subs "SymEngine::is_a<SymEngine::Subs>"(const Basic &b) nogil
@@ -433,6 +437,8 @@ cdef extern from "<symengine/functions.h>" namespace "SymEngine":
     cdef RCP[const Basic] asech(RCP[const Basic] &arg) nogil except+
     cdef RCP[const Basic] function_symbol(string name, const vec_basic &arg) nogil except+
     cdef RCP[const Basic] abs(RCP[const Basic] &arg) nogil except+
+    cdef RCP[const Basic] max(const vec_basic &arg) nogil except+
+    cdef RCP[const Basic] min(const vec_basic &arg) nogil except+
     cdef RCP[const Basic] gamma(RCP[const Basic] &arg) nogil except+
     cdef RCP[const Basic] atan2(RCP[const Basic] &num, RCP[const Basic] &den) nogil except+
 
@@ -539,6 +545,12 @@ cdef extern from "<symengine/functions.h>" namespace "SymEngine":
     cdef cppclass Abs(Function):
         RCP[const Basic] get_arg() nogil
 
+    cdef cppclass Max(Function):
+        pass
+
+    cdef cppclass Min(Function):
+        pass
+
     cdef cppclass Gamma(Function):
         pass
 

symengine/lib/symengine_wrapper.pyx

@@ -45,6 +45,10 @@ cdef c2py(RCP[const symengine.Basic] o):
         r = FunctionSymbol.__new__(FunctionSymbol)
     elif (symengine.is_a_Abs(deref(o))):
         r = Abs.__new__(Abs)
+    elif (symengine.is_a_Max(deref(o))):
+        r = Max.__new__(Max)
+    elif (symengine.is_a_Min(deref(o))):
+        r = Min.__new__(Min)
     elif (symengine.is_a_Gamma(deref(o))):
         r = Gamma.__new__(Gamma)
     elif (symengine.is_a_Derivative(deref(o))):
@@ -208,6 +212,10 @@ def sympy2symengine(a, raise_error=False):
         return log(a.args[0])
     elif isinstance(a, sympy.Abs):
         return abs(sympy2symengine(a.args[0], raise_error))
+    elif isinstance(a, sympy.Max):
+        return _max(*a.args)
+    elif isinstance(a, sympy.Min):
+        return _min(*a.args)
     elif isinstance(a, sympy.gamma):
         return gamma(a.args[0])
     elif isinstance(a, sympy.Derivative):
@@ -659,6 +667,20 @@ cdef class Basic(object):
     def has(self, *symbols):
         return any([has_symbol(self, symbol) for symbol in symbols])
 
+    def args_as_sage(Basic self):
+        cdef symengine.vec_basic Y = deref(self.thisptr).get_args()
+        s = []
+        for i in range(Y.size()):
+            s.append(c2py(<RCP[const symengine.Basic]>(Y[i]))._sage_())
+        return s
+
+    def args_as_sympy(Basic self):
+        cdef symengine.vec_basic Y = deref(self.thisptr).get_args()
+        s = []
+        for i in range(Y.size()):
+            s.append(c2py(<RCP[const symengine.Basic]>(Y[i]))._sympy_())
+        return s
+
 def series(ex, x=None, x0=0, n=6, as_deg_coef_pair=False):
     # TODO: check for x0 an infinity, see sympy/core/expr.py
     # TODO: nonzero x0
@@ -1398,6 +1420,42 @@ cdef class Abs(Function):
         return abs(arg)
 
 
+class Max(Function):
+
+    def __new__(cls, *args):
+        if not args:
+            return super(Max, cls).__new__(cls)
+        return _max(*args)
+
+    def _sympy_(self):
+        import sympy
+        s = self.args_as_sympy()
+        return sympy.Max(*s)
+
+    def _sage_(self):
+        import sage.all as sage
+        s = self.args_as_sage()
+        return sage.max(*s)
+
+
+class Min(Function):
+
+    def __new__(cls, *args):
+        if not args:
+            return super(Min, cls).__new__(cls)
+        return _min(*args)
+
+    def _sympy_(self):
+        import sympy
+        s = self.args_as_sympy()
+        return sympy.Min(*s)
+
+    def _sage_(self):
+        import sage.all as sage
+        s = self.args_as_sage()
+        return sage.min(*s)
+
+
 cdef class Derivative(Basic):
 
     @property
@@ -2342,6 +2400,22 @@ def log(x, y = None):
     cdef Basic Y = _sympify(y)
     return c2py(symengine.log(X.thisptr, Y.thisptr))
 
+def _max(*args):
+    cdef symengine.vec_basic v
+    cdef Basic e_
+    for e in args:
+        e_ = sympify(e)
+        v.push_back(e_.thisptr)
+    return c2py(symengine.max(v))
+
+def _min(*args):
+    cdef symengine.vec_basic v
+    cdef Basic e_
+    for e in args:
+        e_ = sympify(e)
+        v.push_back(e_.thisptr)
+    return c2py(symengine.min(v))
+
 def gamma(x):
     cdef Basic X = _sympify(x)
     return c2py(symengine.gamma(X.thisptr))

symengine/sympy_compat.py

@@ -6,7 +6,7 @@
         ImmutableDenseMatrix, DenseMatrix, Matrix, Derivative, exp,
         nextprime, mod_inverse, primitive_root, Lambdify as lambdify, 
         symarray, diff, eye, diag, ones, zeros, expand, Subs, 
-        FunctionSymbol as AppliedUndef)
+        FunctionSymbol as AppliedUndef, Max, Min)
 from types import ModuleType
 import sys
 

symengine/tests/test_sympy_compat.py

@@ -1,6 +1,6 @@
 from symengine.sympy_compat import (Integer, Rational, S, Basic, Add, Mul,
-    Pow, symbols, Symbol, log, sin, sech, csch, zeros, atan2, Number, Float,
-    symengine)
+    Pow, symbols, Symbol, log, sin, cos, sech, csch, zeros, atan2, Number, Float,
+    symengine, Min, Max)
 from symengine.utilities import raises
 
 
@@ -86,6 +86,38 @@ def test_Pow():
     assert isinstance(i, Basic)
 
 
+def test_Max():
+    x = Symbol("x")
+    y = Symbol("y")
+    z = Symbol("z")
+    assert Max(Integer(6)/3, 1) == 2
+    assert Max(-2, 2) == 2
+    assert Max(2, 2) == 2
+    assert Max(0.2, 0.3) == 0.3
+    assert Max(x, x) == x
+    assert Max(x, y) == Max(y, x)
+    assert Max(x, y, z) == Max(z, y, x)
+    assert Max(x, Max(y, z)) == Max(z, y, x)
+    assert Max(1000, 100, -100, x, y, z) == Max(x, y, z, 1000)
+    assert Max(cos(x), sin(x)) == Max(sin(x), cos(x))
+
+
+def test_Min():
+    x = Symbol("x")
+    y = Symbol("y")
+    z = Symbol("z")
+    assert Min(Integer(6)/3, 1) == 1
+    assert Min(-2, 2) == -2
+    assert Min(2, 2) == 2
+    assert Min(0.2, 0.3) == 0.2
+    assert Min(x, x) == x
+    assert Min(x, y) == Min(y, x)
+    assert Min(x, y, z) == Min(z, y, x)
+    assert Min(x, Min(y, z)) == Min(z, y, x)
+    assert Min(1000, 100, -100, x, y, z) == Min(x, y, z, -100)
+    assert Min(cos(x), sin(x)) == Min(cos(x), sin(x))
+
+
 def test_sin():
     x = symbols("x")
     i = sin(0)