[PATCH 04/10] refactor gcd() a little bit (no functional changes).

[Alexei Sheplyakov-2]

GiNaC tries to avoid expanding expressions while computing GCDs and applies
a number of heuristics. Usually this improves performance, but in some cases
it doesn't. Allow user to switch off heuristics.

Part 4:

refactor gcd() a little bit, so subsequent patch(es) won't be so big and ugly.
---
 ginac/normal.cpp |   41 ++++++++++++++++++++++-------------------
 1 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/ginac/normal.cpp b/ginac/normal.cpp
index 0cb9100..0227f4e 100644
--- a/ginac/normal.cpp
+++ b/ginac/normal.cpp
@@ -1602,33 +1602,36 @@ ex gcd(const ex &a, const ex &b, ex *ca, ex *cb, bool check_args, unsigned optio
  // Try heuristic algorithm first, fall back to PRS if that failed
  ex g;
  bool found = heur_gcd(g, aex, bex, ca, cb, var);
- if (!found) {
-#if STATISTICS
- heur_gcd_failed++;
-#endif
- g = sr_gcd(aex, bex, var);
- if (g.is_equal(_ex1)) {
- // Keep cofactors factored if possible
- if (ca)
- *ca = a;
- if (cb)
- *cb = b;
- } else {
- if (ca)
- divide(aex, g, *ca, false);
- if (cb)
- divide(bex, g, *cb, false);
- }
- } else {
+ if (found) {
+ // heur_gcd have already computed cofactors...
  if (g.is_equal(_ex1)) {
- // Keep cofactors factored if possible
+ // ... but we want to keep them factored if possible.
  if (ca)
  *ca = a;
  if (cb)
  *cb = b;
  }
+ return g;
  }
+#if STATISTICS
+ else {
+ heur_gcd_failed++;
+ }
+#endif
 
+ g = sr_gcd(aex, bex, var);
+ if (g.is_equal(_ex1)) {
+ // Keep cofactors factored if possible
+ if (ca)
+ *ca = a;
+ if (cb)
+ *cb = b;
+ } else {
+ if (ca)
+ divide(aex, g, *ca, false);
+ if (cb)
+ divide(bex, g, *cb, false);
+ }
  return g;
 }
 
--
1.5.6

Best regards,
        Alexei

--
All science is either physics or stamp collecting.



_______________________________________________
GiNaC-devel mailing list
GiNaC-devel@...
https://www.cebix.net/mailman/listinfo/ginac-devel