From 135885db5354dddaa5d88accb8d203fe7072ac7a Mon Sep 17 00:00:00 2001
From: Kasper Peeters <kasper.peeters@cadabra.science>
Date: Fri, 1 Dec 2023 20:10:52 +0000
Subject: [PATCH] Fix a bug in accessing the Weight value in Python. Fix an
 error with setting the multiplier of a node from Python.

---
 core/ExNode.cc                  |  4 ++--
 core/Storage.cc                 |  6 ++++++
 core/Storage.hh                 |  3 ++-
 core/algorithms/substitute.cc   |  6 +++++-
 core/pythoncdb/py_properties.cc |  9 ++++++++-
 tests/programming.cdb           | 15 +++++++++++++++
 6 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/core/ExNode.cc b/core/ExNode.cc
index 8ca46838a9..cbec45be64 100644
--- a/core/ExNode.cc
+++ b/core/ExNode.cc
@@ -325,8 +325,8 @@ void ExNode::set_multiplier(pybind11::object mult)
 	if(!ex->is_valid(it))
 		throw ConsistencyException("Cannot set the multiplier of an iterator before the first 'next'.");
 
-	pybind11::object mpq = pybind11::module::import("gmpy2").attr("mpq");
-	multiply(it->multiplier, pybind11::cast<int>(mult));
+	set(it->multiplier, multiplier_t(mult.attr("numerator").cast<long>(),
+												mult.attr("denominator").cast<long>()) );
 	}
 
 
diff --git a/core/Storage.cc b/core/Storage.cc
index f746a07cda..cc28f0c279 100644
--- a/core/Storage.cc
+++ b/core/Storage.cc
@@ -1014,6 +1014,12 @@ namespace cadabra {
 		num=rat_set.insert(fac).first;
 		}
 
+	void set(rset_t::iterator& num, multiplier_t fac)
+		{
+		fac.canonicalize();
+		num=rat_set.insert(fac).first;
+		}
+
 	void add(rset_t::iterator& num, multiplier_t fac)
 		{
 		fac+=*num;
diff --git a/core/Storage.hh b/core/Storage.hh
index 40757b238a..923e99f0f7 100644
--- a/core/Storage.hh
+++ b/core/Storage.hh
@@ -129,7 +129,8 @@ namespace cadabra {
 	void     one(rset_t::iterator&);
 	void     flip_sign(rset_t::iterator&);
 	void     half(rset_t::iterator&);
-
+	void     set(rset_t::iterator&, multiplier_t);
+	
 	/// \ingroup core
 	///
 	/// Basic storage class for symbolic mathemematical expressions. The
diff --git a/core/algorithms/substitute.cc b/core/algorithms/substitute.cc
index 0c668d9287..6a4f35c676 100644
--- a/core/algorithms/substitute.cc
+++ b/core/algorithms/substitute.cc
@@ -18,7 +18,9 @@ substitute::substitute(const Kernel& k, Ex& tr, Ex& args_, bool partial)
 	{
 	if(args.is_empty()) 
 		throw ArgumentException("substitute: Replacement rule is an empty expression.");
-	
+
+	Stopwatch sw;
+	sw.start();
 	cadabra::do_list(args, args.begin(), [&](Ex::iterator arrow) {
 		//args.print_recursive_treeform(std::cerr, arrow);
 		if(*arrow->name!="\\arrow" && *arrow->name!="\\equals")
@@ -81,6 +83,8 @@ substitute::substitute(const Kernel& k, Ex& tr, Ex& args_, bool partial)
 			}
 		return true;
 		});
+	sw.stop();
+	std::cerr << "preparation took " << sw << std::endl;
 	}
 
 bool substitute::can_apply(iterator st)
diff --git a/core/pythoncdb/py_properties.cc b/core/pythoncdb/py_properties.cc
index 16e5305caa..2d64aaf24a 100644
--- a/core/pythoncdb/py_properties.cc
+++ b/core/pythoncdb/py_properties.cc
@@ -360,7 +360,14 @@ namespace cadabra {
 		def_abstract_prop<Py_DependsBase>(m, "DependsBase")
 			.def("dependencies", [](const Py_DependsBase & p) { return p.get_prop()->dependencies(p.get_kernel(), p.get_it()); });
 		def_abstract_prop<Py_WeightBase>(m, "WeightBase")
-			.def("value", [](const Py_WeightBase & p, const std::string& forcedLabel) { return p.get_prop()->value(p.get_kernel(), p.get_it(), forcedLabel); });
+			.def("value", [](const Py_WeightBase & p, const std::string& forcedLabel) {
+				// This is mpq_class, convert to the Python equivalent.
+				pybind11::object mpq = pybind11::module::import("gmpy2").attr("mpq");
+				auto m = p.get_prop()->value(p.get_kernel(), p.get_it(), forcedLabel);
+				pybind11::object mult = mpq(m.get_num().get_si(), m.get_den().get_si());
+				return mult;
+				});
+
 		def_abstract_prop<Py_DifferentialFormBase>(m, "DifferentialFormBase")
 			.def("degree", [](const Py_DifferentialFormBase & p) { return p.get_prop()->degree(p.get_props(), p.get_it()); });
 
diff --git a/tests/programming.cdb b/tests/programming.cdb
index 2c814bbb20..ea5a3226bf 100644
--- a/tests/programming.cdb
+++ b/tests/programming.cdb
@@ -341,5 +341,20 @@ def test16():
     {i,j,k}::Indices(isospin, position=independent).
     assert($\Lambda_{a}$.matches($\Lambda_{i}$)==False)
     assert($\Lambda_{a}$.matches($\Lambda^{i}$)==False)
+    print("Test 16 passed")
     
 test16()
+
+def test17():
+    x::Weight(value=42, label=field);
+    tst1 = Weight.get($x$, label="field").value("field")
+    assert(tst1==42)
+    print("Test 17a passed")
+    ex:= 3 a;
+    ex.top().multiplier = tst1
+    tst2:= 42 a - @(ex);
+    assert(tst2==0)
+    print("Test 17b passed")
+
+test17()
+