Fix for untrace of traces with single-factor argument.

Author: kpeeters

core/Algorithm.cc

@@ -29,6 +29,7 @@
   #include <boost/core/demangle.hpp>
 #endif
 
+#include "properties/Accent.hh"
 #include "properties/Derivative.hh"
 #include "properties/Indices.hh"
 #include "properties/Coordinate.hh"
@@ -807,9 +808,12 @@ bool Algorithm::is_single_term(iterator it)
 	   && *it->name!="\\comma" && *it->name!="\\equals" && *it->name!="\\arrow") {
 
 		if(tr.is_head(it) || *tr.parent(it)->name=="\\equals" || *tr.parent(it)->name=="\\int") return true;
-		else {
-			if(*tr.parent(it)->name=="\\sum")
-				return true;
+		else if(*tr.parent(it)->name=="\\sum")
+			return true;
+		else if(*tr.parent(it)->name!="\\prod" && it->fl.parent_rel==str_node::parent_rel_t::p_none
+				  && kernel.properties.get<Accent>(tr.parent(it))==0 ) {
+			std::cerr << "Found single term in " << tr.parent(it) << std::endl;
+			return true;
 			}
 		}
 	return false;

core/algorithms/untrace.cc

@@ -19,7 +19,7 @@ bool untrace::can_apply(iterator st)
 		auto sib=tr.begin(st);
 		if(sib==tr.end(st))      return false;
 		if(*sib->name=="\\prod") return true;
-		if(is_single_term(sib))   return true;
+		if(is_single_term(sib))  return true;
 		}
 	return false;
 	}

tests/implicit.cdb

@@ -14,21 +14,31 @@ def test01():
 
 test01()
 
-{a,b,c,d}::Indices(spinor);
-Tr{#}::Trace(indices=spinor);
-#A::ImplicitIndex(A_{a b});
-#B::ImplicitIndex(B_{a b});    
-ex:= Tr( A B A C B );
-untrace(_);
-
+def test02():
+    __cdbkernel__=create_scope()
+    {a,b,c,d}::Indices(spinor);
+    Tr{#}::Trace(indices=spinor);
+    A::ImplicitIndex(A_{a b});
+    B::ImplicitIndex(B_{a b});    
+    ex:= Tr( A B A C B ) - Tr( C );
+    untrace(_);
+    tst:= C Tr( A B A B ) - C Tr(1) - @(ex);
+    assert(tst==0)
+    print("Test 02 passed")
 
-{a,b,c,d}::Indices(spinor);
-\sigma^{\mu}::ImplicitIndex(\sigma^{\mu a}_{b});    
-Tr{#}::Trace(indices=spinor);
-ex:= Tr( \sigma^{\mu} q \sigma^{\nu} );
-untrace(_);
-    
+test02()
+        
+def test03():
+    __cdbkernel__=create_scope()
+    {a,b,c,d}::Indices(spinor);
+    \sigma^{\mu}::ImplicitIndex(\sigma^{\mu a}_{b});    
+    Tr{#}::Trace(indices=spinor);
+    ex:= Tr( \sigma^{\mu} q \sigma^{\nu} );
+    untrace(_);
+    tst:= q Tr( \sigma^{\mu} \sigma^{\nu} ) - @(ex);
+    assert(tst==0)
+    print("Test 03 passed")
 
-
-
+test03()
+