Make Trace inherit explicit indices.

Author: kpeeters

core/algorithms/sort_product.cc

@@ -4,6 +4,8 @@
 
 using namespace cadabra;
 
+#define DEBUG 1
+
 sort_product::sort_product(const Kernel&k, Ex& tr)
 	: Algorithm(k, tr), cleanup(true)
 	{
@@ -63,9 +65,13 @@ Algorithm::result_t sort_product::apply(iterator& st)
 			compare.clear();
 			auto es = compare.equal_subtree(one, two);
 			if(compare.should_swap(one, es)) {
-				// std::cerr << "should swap " << *(one->name) << " with " << *(two->name) << std::endl;
+#ifdef DEBUG
+				std::cerr << "should swap " << *(one->name) << " with " << *(two->name) << std::endl;
+#endif
 				int canswap=compare.can_swap(one, two, es);
-				// std::cerr << "can swap? " << *(one->name) << " with " << *(two->name) << std::endl;
+#ifdef DEBUG
+				std::cerr << "can swap? " << *(one->name) << " with " << *(two->name) << std::endl;
+#endif
 				if(canswap!=0) {
 					// std::cerr << "swapping " << Ex(one) << " with " << Ex(two) << std::endl;
 					tr.swap(one);

core/properties/Trace.hh

@@ -4,10 +4,11 @@
 #include "Props.hh"
 #include "properties/Symmetric.hh"
 #include "properties/Distributable.hh"
+#include "properties/IndexInherit.hh"
 
 namespace cadabra {
 
-	class Trace : public Distributable, virtual public property {
+	class Trace : public Distributable, public IndexInherit, virtual public property {
 		public:
 			Trace();
 			virtual std::string name() const override;

tests/explicit_implicit.cdb

@@ -83,3 +83,18 @@ test05()
 #ex:= \chi \psi \sigma^{n} \chi;
 #explicit_indices(_);
 
+# Normally index contraction aims for adjacent indices.
+# With 'eager=True', contractions are generated as much
+# as possible, even if that does not lead to adjacent indices.
+
+
+# 
+# {m,n,p}::Indices(spacetime, position=fixed);
+# {a,b,c,d,e,f,g,h}::Indices(spinor, position=fixed);
+# \sigma^{p}::ImplicitIndex(\sigma^{p}_{a b});
+# \tau^{p}::ImplicitIndex(\tau^{p a b});
+# \theta::ImplicitIndex(\theta^{a});
+# 
+# ex := \sigma^{p} \theta \tau^{m};
+# tst:= \sigma^{p}_{a b} \theta^{b} \tau^{m a c};
+#