gcd_pf_pow: get rid of duplicate code.

This function (which helps gcd() handle partially factored expressions)
contained two copies of the same code. Remove one redundant copy.

diff --git a/ginac/normal.cpp b/ginac/normal.cpp
index d5319b9b771895087a01973e9186100e195a9972..6392e3f144648814b384f71ea4d612e3b683c84f 100644 (file)
--- a/ginac/normal.cpp
+++ b/ginac/normal.cpp
@@ -1691,65 +1691,39 @@ static ex gcd_pf_pow_pow(const ex& a, const ex& b, ex* ca, ex* cb)
 
 static ex gcd_pf_pow(const ex& a, const ex& b, ex* ca, ex* cb)
 {
 
 static ex gcd_pf_pow(const ex& a, const ex& b, ex* ca, ex* cb)
 {

-       if (is_exactly_a<power>(a)) {
-               ex p = a.op(0);
-               const ex& exp_a = a.op(1);
-               if (is_exactly_a<power>(b))
-                       return gcd_pf_pow_pow(a, b, ca, cb);
-               else {
-                       if (p.is_equal(b)) {
-                               // a = p^n, b = p, gcd = p
-                               if (ca)
-                                       *ca = power(p, a.op(1) - 1);
-                               if (cb)
-                                       *cb = _ex1;
-                               return p;
-                       } 
+       if (is_exactly_a<power>(a) && is_exactly_a<power>(b))
+               return gcd_pf_pow_pow(a, b, ca, cb);

 
 

-                       ex p_co, bpart_co;
-                       ex p_gcd = gcd(p, b, &p_co, &bpart_co, false);
+       if (is_exactly_a<power>(b) && (! is_exactly_a<power>(a)))
+               return gcd_pf_pow(b, a, cb, ca);

 
 

-                       if (p_gcd.is_equal(_ex1)) {
-                               // a(x) = p(x)^n, gcd(p, b) = 1 ==> gcd(a, b) = 1
-                               if (ca)
-                                       *ca = a;
-                               if (cb)
-                                       *cb = b;
-                               return _ex1;
-                       } else {
-                               // a(x) = g(x)^n A(x)^n, b(x) = g(x) B(x) ==> gcd(a, b) = g(x) gcd(g(x)^(n-1) A(x)^n, B(x))
-                               return p_gcd*gcd(power(p_gcd, exp_a-1)*power(p_co, exp_a), bpart_co, ca, cb, false);
-                       }
-               } // is_exactly_a<power>(b)
+       GINAC_ASSERT(is_exactly_a<power>(a));

 
 

-       } else if (is_exactly_a<power>(b)) {
-               ex p = b.op(0);
-               if (p.is_equal(a)) {
-                       // a = p, b = p^n, gcd = p
-                       if (ca)
-                               *ca = _ex1;
-                       if (cb)
-                               *cb = power(p, b.op(1) - 1);
-                       return p;
-               }
+       ex p = a.op(0);
+       const ex& exp_a = a.op(1);
+       if (p.is_equal(b)) {
+               // a = p^n, b = p, gcd = p
+               if (ca)
+                       *ca = power(p, a.op(1) - 1);
+               if (cb)
+                       *cb = _ex1;
+               return p;
+       } 

 
 

-               ex p_co, apart_co;
-               const ex& exp_b(b.op(1));
-               ex p_gcd = gcd(a, p, &apart_co, &p_co, false);
-               if (p_gcd.is_equal(_ex1)) {
-                       // b=p(x)^n, gcd(a, p) = 1 ==> gcd(a, b) == 1
-                       if (ca)
-                               *ca = a;
-                       if (cb)
-                               *cb = b;
-                       return _ex1;
-               } else {
-                       // there are common factors:
-                       // a(x) = g(x) A(x), b(x) = g(x)^n B(x)^n ==> gcd = g(x) gcd(g(x)^(n-1) A(x)^n, B(x))
+       ex p_co, bpart_co;
+       ex p_gcd = gcd(p, b, &p_co, &bpart_co, false);

 
 

-                       return p_gcd*gcd(apart_co, power(p_gcd, exp_b-1)*power(p_co, exp_b), ca, cb, false);
-               } // p_gcd.is_equal(_ex1)
+       // a(x) = p(x)^n, gcd(p, b) = 1 ==> gcd(a, b) = 1
+       if (p_gcd.is_equal(_ex1)) {
+               if (ca)
+                       *ca = a;
+               if (cb)
+                       *cb = b;
+               return _ex1;

        }
        }

+       // a(x) = g(x)^n A(x)^n, b(x) = g(x) B(x) ==> gcd(a, b) = g(x) gcd(g(x)^(n-1) A(x)^n, B(x))
+       ex rg = gcd(power(p_gcd, exp_a-1)*power(p_co, exp_a), bpart_co, ca, cb, false);
+       return p_gcd*rg;

 }
 
 static ex gcd_pf_mul(const ex& a, const ex& b, ex* ca, ex* cb)
 }
 
 static ex gcd_pf_mul(const ex& a, const ex& b, ex* ca, ex* cb)