Add proper functions to make clifford_bar() and clifford_star().

[ginac.git] / ginac / clifford.cpp

diff --git a/ginac/clifford.cpp b/ginac/clifford.cpp
index 57d6ce6d1e725c215c654f6e558ea9f24a5b1c17..311ef216d23a5e7bd90261d5c0c80abad77e7809 100644 (file)
--- a/ginac/clifford.cpp
+++ b/ginac/clifford.cpp
@@ -1087,6 +1087,47 @@ next_sym:        ;
        }
 }
 
+ex clifford_star_bar(const ex & e, bool do_bar, unsigned options)
+{
+       pointer_to_map_function_2args<bool, unsigned> fcn(clifford_star_bar, do_bar, options | 1);
+
+       // is a child, no need to expand
+       ex e1= (options & 1 ? e : e.expand());
+
+       if (is_a<ncmul>(e1) ) { // reversing order of clifford units
+               exvector ev, cv;
+               ev.reserve(e1.nops());
+               cv.reserve(e1.nops());
+               // separate clifford and non-clifford entries
+               for (int i= 0; i < e1.nops(); ++i) {
+                       if (is_a<clifford>(e1.op(i)) && is_a<cliffordunit>(e1.op(i).op(0)))
+                               cv.push_back(e1.op(i));
+                       else
+                               ev.push_back(e1.op(i));
+               }
+               for (auto i=cv.rbegin(); i!=cv.rend(); ++i) { // reverse order of Clifford units
+                       ev.push_back(i->conjugate());
+               }
+               // For clifford_bar an odd number of clifford units reverts the sign
+               if (do_bar && (cv.size() % 2 == 1))
+                       return -dynallocate<ncmul>(std::move(ev));
+               else
+                       return dynallocate<ncmul>(std::move(ev));
+       } else if (is_a<clifford>(e1) && is_a<cliffordunit>(e1.op(0))) {
+               if (do_bar)
+                       return -e;
+               else
+                       return e;
+       } else if (is_a<power>(e1)) {
+               // apply the procedure to the base of a power
+               return pow(clifford_star_bar(e1.op(0), do_bar, 0), e1.op(1));
+       } else if (is_a<add>(e1) || is_a<mul>(e1) || e.info(info_flags::list)) {
+               // recurse into subexpressions
+               return e1.map(fcn);
+       } else  // nothing meaningful can be done
+               return e;
+}
+
 ex clifford_prime(const ex & e)
 {
        pointer_to_map_function fcn(clifford_prime);