make atan2 handle positive arguments better. We have pos. symbols nowadays.
authorChris Dams <Chris.Dams@mi.infn.it>
Wed, 22 Nov 2006 21:50:11 +0000 (21:50 +0000)
committerChris Dams <Chris.Dams@mi.infn.it>
Wed, 22 Nov 2006 21:50:11 +0000 (21:50 +0000)
ginac/inifcns_trans.cpp

index 657cdfabb51275372934cd49ff96a813f606757d..40402bb6cd87df33f0eea48dc1469bf13ad3143d 100644 (file)
@@ -820,69 +820,67 @@ static ex atan2_evalf(const ex &y, const ex &x)
 
 static ex atan2_eval(const ex & y, const ex & x)
 {
-       if (y.info(info_flags::numeric) && x.info(info_flags::numeric)) {
+       if (y.is_zero()) {
 
-               if (y.is_zero()) {
+               // atan(0, 0) -> 0
+               if (x.is_zero())
+                       return _ex0;
 
-                       // atan(0, 0) -> 0
-                       if (x.is_zero())
-                               return _ex0;
+               // atan(0, x), x real and positive -> 0
+               if (x.info(info_flags::positive))
+                       return _ex0;
 
-                       // atan(0, x), x real and positive -> 0
-                       if (x.info(info_flags::positive))
-                               return _ex0;
+               // atan(0, x), x real and negative -> -Pi
+               if (x.info(info_flags::negative))
+                       return _ex_1*Pi;
+       }
 
-                       // atan(0, x), x real and negative -> -Pi
-                       if (x.info(info_flags::negative))
-                               return _ex_1*Pi;
-               }
+       if (x.is_zero()) {
 
-               if (x.is_zero()) {
+               // atan(y, 0), y real and positive -> Pi/2
+               if (y.info(info_flags::positive))
+                       return _ex1_2*Pi;
 
-                       // atan(y, 0), y real and positive -> Pi/2
-                       if (y.info(info_flags::positive))
-                               return _ex1_2*Pi;
+               // atan(y, 0), y real and negative -> -Pi/2
+               if (y.info(info_flags::negative))
+                       return _ex_1_2*Pi;
+       }
 
-                       // atan(y, 0), y real and negative -> -Pi/2
-                       if (y.info(info_flags::negative))
-                               return _ex_1_2*Pi;
-               }
+       if (y.is_equal(x)) {
 
-               if (y.is_equal(x)) {
+               // atan(y, y), y real and positive -> Pi/4
+               if (y.info(info_flags::positive))
+                       return _ex1_4*Pi;
 
-                       // atan(y, y), y real and positive -> Pi/4
-                       if (y.info(info_flags::positive))
-                               return _ex1_4*Pi;
+               // atan(y, y), y real and negative -> -3/4*Pi
+               if (y.info(info_flags::negative))
+                       return numeric(-3, 4)*Pi;
+       }
 
-                       // atan(y, y), y real and negative -> -3/4*Pi
-                       if (y.info(info_flags::negative))
-                               return numeric(-3, 4)*Pi;
-               }
+       if (y.is_equal(-x)) {
 
-               if (y.is_equal(-x)) {
+               // atan(y, -y), y real and positive -> 3*Pi/4
+               if (y.info(info_flags::positive))
+                       return numeric(3, 4)*Pi;
 
-                       // atan(y, -y), y real and positive -> 3*Pi/4
-                       if (y.info(info_flags::positive))
-                               return numeric(3, 4)*Pi;
+               // atan(y, -y), y real and negative -> -Pi/4
+               if (y.info(info_flags::negative))
+                       return _ex_1_4*Pi;
+       }
 
-                       // atan(y, -y), y real and negative -> -Pi/4
-                       if (y.info(info_flags::negative))
-                               return _ex_1_4*Pi;
-               }
+       // atan(float, float) -> float
+       if (is_a<numeric>(y) && is_a<numeric>(x) && !y.info(info_flags::crational)
+                       && !x.info(info_flags::crational))
+               return atan(ex_to<numeric>(y), ex_to<numeric>(x));
 
-               // atan(float, float) -> float
-               if (!y.info(info_flags::crational) && !x.info(info_flags::crational))
-                       return atan(ex_to<numeric>(y), ex_to<numeric>(x));
-
-               // atan(real, real) -> atan(y/x) +/- Pi
-               if (y.info(info_flags::real) && x.info(info_flags::real)) {
-                       if (x.info(info_flags::positive))
-                               return atan(y/x);
-                       else if(y.info(info_flags::positive))
-                               return atan(y/x)+Pi;
-                       else
-                               return atan(y/x)-Pi;
-               }
+       // atan(real, real) -> atan(y/x) +/- Pi
+       if (y.info(info_flags::real) && x.info(info_flags::real)) {
+               if (x.info(info_flags::positive))
+                       return atan(y/x);
+               else if(y.info(info_flags::positive))
+                       return atan(y/x)+Pi;
+               else
+                       return atan(y/x)-Pi;
        }
 
        return atan2(y, x).hold();