Improve performance of complex logarithm (#26)

by using real functions when possible --------- Co-authored-by: Alexander Voigt <[email protected]>
Expander · Feb 21, 2024 · fad19d6 · fad19d6
1 parent ab3a8b0
commit fad19d6
Showing 1 changed file with 12 additions and 2 deletions.
diff --git a/src/Log.jl b/src/Log.jl
@@ -9,7 +9,13 @@ end
 # returns complex logarithm of z;
 # handles case when imag(z) == -0.0
 function clog(z::Complex)
-    log(convert_minus_0(z))
+    if iszero(imag(z)) && real(z) > zero(real(z))
+        Complex(log(real(z)), zero(real(z)))
+    elseif iszero(imag(z))
+        Complex(log(real(-z)), convert(typeof(real(z)),pi))
+    else
+        log(z)
+    end
 end
 
 # returns logarithm of x
@@ -20,7 +26,11 @@ end
 # returns complex logarithm of 1+z;
 # handles case when imag(z) == -0.0
 function clog1p(z::Complex)
-    log1p(convert_minus_0(z))
+    if iszero(imag(z)) && real(z) > -one(real(z))
+        Complex(log1p(real(z)), zero(real(z)))
+    else
+        log1p(convert_minus_0(z))
+    end
 end
 
 # returns |ln(x)|^2 for all x