Merge pull request #2077 from anutosh491/GSoC_PR5

Added support for symbolic Expand & Differentiation

Author: certik

integration_tests/CMakeLists.txt

@@ -602,6 +602,7 @@ RUN(NAME symbolics_01        LABELS cpython_sym c_sym)
 RUN(NAME symbolics_02        LABELS cpython_sym c_sym)
 RUN(NAME symbolics_03        LABELS cpython_sym c_sym)
 RUN(NAME symbolics_04        LABELS cpython_sym c_sym)
+RUN(NAME symbolics_05        LABELS cpython_sym c_sym)
 
 RUN(NAME sizeof_01           LABELS llvm c
         EXTRAFILES sizeof_01b.c)

integration_tests/symbolics_05.py

@@ -0,0 +1,24 @@
+from sympy import Symbol, expand, diff
+from lpython import S
+
+def test_operations():
+    x: S = Symbol('x')
+    y: S = Symbol('y')
+    z: S = Symbol('z')
+    a: S = (x + y)**S(2)
+    b: S = (x + y + z)**S(3)
+
+    # test expand
+    assert(a.expand() == S(2)*x*y + x**S(2) + y**S(2))
+    assert(expand(b) == S(3)*x*y**S(2) + S(3)*x*z**S(2) + S(3)*x**S(2)*y + S(3)*x**S(2)*z +\
+    S(3)*y*z**S(2) + S(3)*y**S(2)*z + S(6)*x*y*z + x**S(3) + y**S(3) + z**S(3))
+    print(a.expand())
+    print(expand(b))
+
+    # test diff
+    assert(a.diff(x) == S(2)*(x + y))
+    assert(diff(b, x) == S(3)*(x + y + z)**S(2))
+    print(a.diff(x))
+    print(diff(b, x))
+
+test_operations()

src/libasr/codegen/asr_to_c_cpp.h

@@ -2755,6 +2755,10 @@ PyMODINIT_FUNC PyInit_lpython_module_)" + fn_name + R"((void) {
                 src = performSymbolicOperation("basic_pow", x);
                 return;
             }
+            case (static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicDiff)): {
+                src = performSymbolicOperation("basic_diff", x);
+                return;
+            }
             case (static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicPi)): {
                 headers.insert("symengine/cwrapper.h");
                 LCOMPILERS_ASSERT(x.n_args == 0);
@@ -2781,6 +2785,22 @@ PyMODINIT_FUNC PyInit_lpython_module_)" + fn_name + R"((void) {
                 src = target;
                 return;
             }
+            case (static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicExpand)): {
+                headers.insert("symengine/cwrapper.h");
+                LCOMPILERS_ASSERT(x.n_args == 1);
+                std::string target = symengine_queue.push();
+                std::string target_src = symengine_src;
+                this->visit_expr(*x.m_args[0]);
+                std::string arg1 = src;
+                std::string arg1_src = symengine_src;
+                if (ASR::is_a<ASR::Var_t>(*x.m_args[0])) {
+                    symengine_queue.pop();
+                }
+                symengine_src = target_src + arg1_src;
+                symengine_src += indent + "basic_expand(" + target + ", " + arg1 + ");\n";
+                src = target;
+                return;
+            }
             default : {
                 throw LCompilersException("IntrinsicFunction: `"
                     + ASRUtils::get_intrinsic_name(x.m_intrinsic_id)

src/libasr/pass/intrinsic_function_registry.h

@@ -72,6 +72,8 @@ enum class IntrinsicFunctions : int64_t {
     SymbolicPow,
     SymbolicPi,
     SymbolicInteger,
+    SymbolicDiff,
+    SymbolicExpand,
     Sum,
     // ...
 };
@@ -2056,7 +2058,7 @@ namespace SymbolicSymbol {
 
 } // namespace SymbolicSymbol
 
-#define create_symbolic_binop_macro(X)                                                     \
+#define create_symbolic_binary_macro(X)                                                     \
 namespace X{                                                                               \
                                                                                            \
     static inline void verify_args(const ASR::IntrinsicFunction_t& x,                      \
@@ -2107,11 +2109,12 @@ namespace X{
     }                                                                                      \
 } // namespace X
 
-create_symbolic_binop_macro(SymbolicAdd)
-create_symbolic_binop_macro(SymbolicSub)
-create_symbolic_binop_macro(SymbolicMul)
-create_symbolic_binop_macro(SymbolicDiv)
-create_symbolic_binop_macro(SymbolicPow)
+create_symbolic_binary_macro(SymbolicAdd)
+create_symbolic_binary_macro(SymbolicSub)
+create_symbolic_binary_macro(SymbolicMul)
+create_symbolic_binary_macro(SymbolicDiv)
+create_symbolic_binary_macro(SymbolicPow)
+create_symbolic_binary_macro(SymbolicDiff)
 
 namespace SymbolicPi {
 
@@ -2166,6 +2169,46 @@ namespace SymbolicInteger {
     }
 } // namespace SymbolicInteger
 
+namespace SymbolicExpand {
+
+    static inline void verify_args(const ASR::IntrinsicFunction_t& x, diag::Diagnostics& diagnostics) {
+        const Location& loc = x.base.base.loc;
+        ASRUtils::require_impl(x.n_args == 1,
+            "SymbolicExpand must have exactly 1 input argument",
+            loc, diagnostics);
+
+        ASR::ttype_t* input_type = ASRUtils::expr_type(x.m_args[0]);
+        ASRUtils::require_impl(ASR::is_a<ASR::SymbolicExpression_t>(*input_type),
+            "SymbolicExpand expects an argument of type SymbolicExpression",
+            x.base.base.loc, diagnostics);
+    }
+
+    static inline ASR::expr_t *eval_SymbolicExpand(Allocator &/*al*/,
+    const Location &/*loc*/, Vec<ASR::expr_t*>& /*args*/) {
+        // TODO
+        return nullptr;
+    }
+
+    static inline ASR::asr_t* create_SymbolicExpand(Allocator& al, const Location& loc,
+            Vec<ASR::expr_t*>& args,
+            const std::function<void (const std::string &, const Location &)> err) {
+        if (args.size() != 1) {
+            err("Intrinsic expand function accepts exactly 1 argument", loc);
+        }
+
+        ASR::ttype_t* argtype = ASRUtils::expr_type(args[0]);
+        if(!ASR::is_a<ASR::SymbolicExpression_t>(*argtype)) {
+            err("Argument of SymbolicExpand function must be of type SymbolicExpression",
+            args[0]->base.loc);
+        }
+
+        ASR::ttype_t *to_type = ASRUtils::TYPE(ASR::make_SymbolicExpression_t(al, loc));
+        return UnaryIntrinsicFunction::create_UnaryFunction(al, loc, args, eval_SymbolicExpand,
+            static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicExpand), 0, to_type);
+    }
+
+} // namespace SymbolicExpand
+
 namespace IntrinsicFunctionRegistry {
 
     static const std::map<int64_t,
@@ -2228,6 +2271,10 @@ namespace IntrinsicFunctionRegistry {
             {nullptr, &SymbolicPi::verify_args}},
         {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicInteger),
             {nullptr, &SymbolicInteger::verify_args}},
+        {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicDiff),
+            {nullptr, &SymbolicDiff::verify_args}},
+        {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicExpand),
+            {nullptr, &SymbolicExpand::verify_args}},
     };
 
     static const std::map<int64_t, std::string>& intrinsic_function_id_to_name = {
@@ -2282,6 +2329,10 @@ namespace IntrinsicFunctionRegistry {
             "pi"},
         {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicInteger),
             "SymbolicInteger"},
+        {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicDiff),
+            "SymbolicDiff"},
+        {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::SymbolicExpand),
+            "SymbolicExpand"},
         {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::Any),
             "any"},
         {static_cast<int64_t>(ASRUtils::IntrinsicFunctions::Sum),
@@ -2319,6 +2370,8 @@ namespace IntrinsicFunctionRegistry {
                 {"SymbolicPow", {&SymbolicPow::create_SymbolicPow, &SymbolicPow::eval_SymbolicPow}},
                 {"pi", {&SymbolicPi::create_SymbolicPi, &SymbolicPi::eval_SymbolicPi}},
                 {"SymbolicInteger", {&SymbolicInteger::create_SymbolicInteger, &SymbolicInteger::eval_SymbolicInteger}},
+                {"diff", {&SymbolicDiff::create_SymbolicDiff, &SymbolicDiff::eval_SymbolicDiff}},
+                {"expand", {&SymbolicExpand::create_SymbolicExpand, &SymbolicExpand::eval_SymbolicExpand}},
     };
 
     static inline bool is_intrinsic_function(const std::string& name) {
@@ -2433,6 +2486,8 @@ inline std::string get_intrinsic_name(int x) {
         INTRINSIC_NAME_CASE(SymbolicPow)
         INTRINSIC_NAME_CASE(SymbolicPi)
         INTRINSIC_NAME_CASE(SymbolicInteger)
+        INTRINSIC_NAME_CASE(SymbolicDiff)
+        INTRINSIC_NAME_CASE(SymbolicExpand)
         INTRINSIC_NAME_CASE(Sum)
         default : {
             throw LCompilersException("pickle: intrinsic_id not implemented");

src/lpython/semantics/python_ast_to_asr.cpp

@@ -694,6 +694,11 @@ class CommonVisitor : public AST::BaseVisitor<Struct> {
         return;
     }
 
+    void handle_symbolic_attribute(ASR::expr_t *s, std::string attr_name,
+                const Location &loc, Vec<ASR::expr_t*> &args) {
+        tmp = attr_handler.get_symbolic_attribute(s, attr_name, al, loc, args, diag);
+        return;
+    }
 
     void fill_expr_in_ttype_t(std::vector<ASR::expr_t*>& exprs, ASR::dimension_t* dims, size_t n_dims) {
         for( size_t i = 0; i < n_dims; i++ ) {
@@ -7113,6 +7118,11 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
                             handle_string_attributes(se, args, at->m_attr, loc);
                             return;
                         }
+                        ASR::ttype_t *type = ASRUtils::expr_type(se);
+                        if (ASR::is_a<ASR::SymbolicExpression_t>(*type)) {
+                            handle_symbolic_attribute(se, at->m_attr, loc, eles);
+                            return;
+                        }
                         handle_builtin_attribute(se, at->m_attr, loc, eles);
                         return;
                     }
@@ -7231,7 +7241,7 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
 
         if (!s) {
             std::set<std::string> not_cpython_builtin = {
-                "sin", "cos", "gamma", "tan", "asin", "acos", "atan", "sinh", "cosh", "tanh", "exp", "exp2", "expm1", "Symbol",
+                "sin", "cos", "gamma", "tan", "asin", "acos", "atan", "sinh", "cosh", "tanh", "exp", "exp2", "expm1", "Symbol", "diff", "expand",
                 "sum" // For sum called over lists
             };
             if (ASRUtils::IntrinsicFunctionRegistry::is_intrinsic_function(call_name) &&

src/lpython/semantics/python_attribute_eval.h

@@ -15,7 +15,7 @@ struct AttributeHandler {
     typedef ASR::asr_t* (*attribute_eval_callback)(ASR::expr_t*, Allocator &,
                                 const Location &, Vec<ASR::expr_t*> &, diag::Diagnostics &);
 
-    std::map<std::string, attribute_eval_callback> attribute_map;
+    std::map<std::string, attribute_eval_callback> attribute_map, symbolic_attribute_map;
     std::set<std::string> modify_attr_set;
 
     AttributeHandler() {
@@ -40,6 +40,11 @@ struct AttributeHandler {
         modify_attr_set = {"list@append", "list@remove",
             "list@reverse", "list@clear", "list@insert", "list@pop",
             "set@pop", "set@add", "set@remove", "dict@pop"};
+
+        symbolic_attribute_map = {
+            {"diff", &eval_symbolic_diff},
+            {"expand", &eval_symbolic_expand}
+        };
     }
 
     std::string get_type_name(ASR::ttype_t *t) {
@@ -82,6 +87,19 @@ struct AttributeHandler {
         }
     }
 
+    ASR::asr_t* get_symbolic_attribute(ASR::expr_t *e, std::string attr_name,
+            Allocator &al, const Location &loc, Vec<ASR::expr_t*> &args, diag::Diagnostics &diag) {
+        std::string key = attr_name;
+        auto search = symbolic_attribute_map.find(key);
+        if (search != symbolic_attribute_map.end()) {
+            attribute_eval_callback cb = search->second;
+            return cb(e, al, loc, args, diag);
+        } else {
+            throw SemanticError("S." + attr_name + " is not implemented yet",
+                loc);
+        }
+    }
+
     static ASR::asr_t* eval_int_bit_length(ASR::expr_t *s, Allocator &al, const Location &loc,
             Vec<ASR::expr_t*> &args, diag::Diagnostics &/*diag*/) {
         if (args.size() != 0) {
@@ -388,6 +406,34 @@ struct AttributeHandler {
         return make_DictPop_t(al, loc, s, args[0], value_type, nullptr);
     }
 
+    static ASR::asr_t* eval_symbolic_diff(ASR::expr_t *s, Allocator &al, const Location &loc,
+            Vec<ASR::expr_t*> &args, diag::Diagnostics &/*diag*/) {
+        Vec<ASR::expr_t*> args_with_list;
+        args_with_list.reserve(al, args.size() + 1);
+        args_with_list.push_back(al, s);
+        for(size_t i = 0; i < args.size(); i++) {
+            args_with_list.push_back(al, args[i]);
+        }
+        ASRUtils::create_intrinsic_function create_function =
+            ASRUtils::IntrinsicFunctionRegistry::get_create_function("diff");
+        return create_function(al, loc, args_with_list, [&](const std::string &msg, const Location &loc)
+                                { throw SemanticError(msg, loc); });
+    }
+
+    static ASR::asr_t* eval_symbolic_expand(ASR::expr_t *s, Allocator &al, const Location &loc,
+            Vec<ASR::expr_t*> &args, diag::Diagnostics &/*diag*/) {
+        Vec<ASR::expr_t*> args_with_list;
+        args_with_list.reserve(al, args.size() + 1);
+        args_with_list.push_back(al, s);
+        for(size_t i = 0; i < args.size(); i++) {
+            args_with_list.push_back(al, args[i]);
+        }
+        ASRUtils::create_intrinsic_function create_function =
+            ASRUtils::IntrinsicFunctionRegistry::get_create_function("expand");
+        return create_function(al, loc, args_with_list, [&](const std::string &msg, const Location &loc)
+                                { throw SemanticError(msg, loc); });
+    }
+
 }; // AttributeHandler
 
 } // namespace LCompilers::LPython