Adapted exp() for complex numbers so that it correctly treats the corner cases +/-inf and NaN.

Author: JorisDeRidder

src/lib.rs

@@ -193,9 +193,28 @@ impl<T: Float> Complex<T> {
     /// Computes `e^(self)`, where `e` is the base of the natural logarithm.
     #[inline]
     pub fn exp(self) -> Self {
-        // formula: e^(a + bi) = e^a (cos(b) + i*sin(b))
-        // = from_polar(e^a, b)
-        Self::from_polar(self.re.exp(), self.im)
+        // formula: e^(a + bi) = e^a (cos(b) + i*sin(b)) = from_polar(e^a, b)
+        
+        // Treat the corner cases +∞, -∞, and NaN
+        let mut im = self.im;
+        if self.re.is_infinite() {
+            if self.re < T::zero() {
+                if !self.im.is_finite() {
+                    im = T::one();
+                }
+            } else {
+                if self.im == T::zero() || !self.im.is_finite() {
+                    if self.im.is_infinite() {
+                        im = T::nan();
+                    }
+                    return Self::new(self.re, im);
+                }
+            }
+        } else if self.re.is_nan() && self.im == T::zero() {
+                return self;
+        } 
+
+        Self::from_polar(self.re.exp(), im)
     }
 
     /// Computes the principal value of natural logarithm of `self`.