- color and clifford classes are quite functional now

[ginac.git] / ginac / color.cpp

diff --git a/ginac/color.cpp b/ginac/color.cpp
index 77cf89c44dee8dc4d98e0dd1f6eeb948727fb45f..9e719ec051cecbb914e3e1b59138f8e4cd8286c4 100644 (file)
--- a/ginac/color.cpp
+++ b/ginac/color.cpp
@@ -154,10 +154,11 @@ DEFAULT_PRINT(su3d, "d")
  *  objects. This removes superfluous ONEs. */
 ex color::simplify_ncmul(const exvector & v) const
 {
-       //!! TODO: sort by representation label
        exvector s;
        s.reserve(v.size());
+       unsigned rl = ex_to_color(v[0]).get_representation_label();
 
+       // Remove superfluous ONEs
        exvector::const_iterator it = v.begin(), itend = v.end();
        while (it != itend) {
                if (!is_ex_of_type(it->op(0), su3one))
@@ -166,9 +167,7 @@ ex color::simplify_ncmul(const exvector & v) const
        }
 
        if (s.size() == 0)
-               return color(su3one());
-       else if (s.size() == v.size())
-               return simplified_ncmul(v);
+               return color(su3one(), rl);
        else
                return simplified_ncmul(s);
 }
@@ -297,6 +296,56 @@ ex su3f::eval_indexed(const basic & i) const
 }
 
 
+/** Contraction of generator with something else. */
+bool su3t::contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const
+{
+       GINAC_ASSERT(is_ex_of_type(*self, indexed));
+       GINAC_ASSERT(is_ex_of_type(*other, indexed));
+       GINAC_ASSERT(self->nops() == 2);
+       GINAC_ASSERT(is_ex_of_type(self->op(0), su3t));
+       unsigned char rl = ex_to_color(*self).get_representation_label();
+
+       if (is_ex_exactly_of_type(other->op(0), su3t)) {
+
+               // T.a T.a = 4/3 ONE
+               if (other - self == 1) {
+                       *self = numeric(4, 3);
+                       *other = color_ONE(rl);
+                       return true;
+
+               // T.a T.b T.a = -1/6 T.b
+               } else if (other - self == 2
+                       && is_ex_of_type(self[1], color)) {
+                       *self = numeric(-1, 6);
+                       *other = _ex1();
+                       return true;
+
+               // T.a S T.a = 1/2 Tr(S) - 1/6 S
+               } else {
+                       exvector::iterator it = self + 1;
+                       while (it != other) {
+                               if (!is_ex_of_type(*it, color)) {
+                                       return false;
+                               }
+                               it++;
+                       }
+
+                       it = self + 1;
+                       ex S = _ex1();
+                       while (it != other) {
+                               S *= *it;
+                               *it++ = _ex1();
+                       }
+
+                       *self = color_trace(S, rl) * color_ONE(rl) / 2 - S / 6;
+                       *other = _ex1();
+                       return true;
+               }
+       }
+
+       return false;
+}
+
 /** Contraction of an indexed symmetric structure constant with something else. */
 bool su3d::contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const
 {