Support pickling of Basic objects

Author: isuruf

symengine/lib/symengine.pxd

@@ -183,6 +183,8 @@ cdef extern from "<symengine/basic.h>" namespace "SymEngine":
         unsigned int hash() nogil except +
         vec_basic get_args() nogil
         int __cmp__(const Basic &o) nogil
+        string dumps() nogil except +
+
     ctypedef RCP[const Number] rcp_const_number "SymEngine::RCP<const SymEngine::Number>"
     ctypedef unordered_map[int, rcp_const_basic] umap_int_basic "SymEngine::umap_int_basic"
     ctypedef unordered_map[int, rcp_const_basic].iterator umap_int_basic_iterator "SymEngine::umap_int_basic::iterator"
@@ -193,6 +195,7 @@ cdef extern from "<symengine/basic.h>" namespace "SymEngine":
     bool eq(const Basic &a, const Basic &b) nogil except +
     bool neq(const Basic &a, const Basic &b) nogil except +
 
+    RCP[const Basic] loads "SymEngine::Basic::loads"(const string &) nogil except +
 
     RCP[const Symbol] rcp_static_cast_Symbol "SymEngine::rcp_static_cast<const SymEngine::Symbol>"(rcp_const_basic &b) nogil
     RCP[const PySymbol] rcp_static_cast_PySymbol "SymEngine::rcp_static_cast<const SymEngine::PySymbol>"(rcp_const_basic &b) nogil

symengine/lib/symengine_wrapper.pyx

@@ -826,6 +826,10 @@ cdef list vec_pair_to_list(symengine.vec_pair& vec):
     return result
 
 
+def load_basic(bytes s):
+    return c2py(symengine.loads(s))
+
+
 repr_latex=[False]
 
 cdef class Basic(object):
@@ -836,6 +840,10 @@ cdef class Basic(object):
     def __repr__(self):
         return self.__str__()
 
+    def __reduce__(self):
+        cdef bytes s = deref(self.thisptr).dumps()
+        return (load_basic, (s,))
+
     def _repr_latex_(self):
         if repr_latex[0]:
             return "${}$".format(latex(self))

symengine/tests/test_pickling.py

@@ -1,7 +1,16 @@
-from symengine import symbols, sin, sinh, have_numpy, have_llvm
+from symengine import symbols, sin, sinh, have_numpy, have_llvm, cos
 import pickle
 import unittest
 
+
+def test_basic():
+    x, y, z = symbols('x y z')
+    expr = sin(cos(x + y)/z)**2
+    s = pickle.dumps(expr)
+    expr2 = pickle.loads(s)
+    assert expr == expr2
+
+
 @unittest.skipUnless(have_llvm, "No LLVM support")
 @unittest.skipUnless(have_numpy, "Numpy not installed")
 def test_llvm_double():

symengine_version.txt

@@ -1 +1 @@
-23abf31763620463500d5fad114d855afd66d011
+4b841d144bbc1ecd4367e4bd7dd4e7c6be8fac05