Save any unsaved work before trying as it may crash Mathematica and other programs by filling up the memory!
In v18.104.22.168 on OSX 10.8.5, if I start a new session and define two functions
f1P = Sin[#^Sin[Sqrt[Gamma[#]]]] &;
f2P = Sin[#^Sin[Gamma[(# + 1)]]] &;
they both work fine. Now, if I quit the kernel and define the exact same functions but removing the
;s when I evaluate the cell with
f1P = Sin[#^Sin[Sqrt[Gamma[#]]]] &
I get some output (
Sin[#^Sin[Sqrt[Gamma[#]]]] &). Then if I try to evaluate the cell with the second function definition the kernel hangs indefinitely. In fact the kernel can't handle the definition of
; at all (if I try to give it values nothing happens). Strangely, this isn't the case with
f2P: I remove the semicolon, evaluate and it runs fine. But with
f1P the kernel consumes more and more
CPU memory. I have not idea why CPU usage spiked yesterday - I tried this today and it increased to ~35% but not more. The memory demand keeps growing though until the Kernel gets terminated or until Mathematica crashes.
This seems to be a bug with Mathematica on OSX as other people confirmed and I have now reported it to WR so I will edit again once I have confirmation from them. Still, if anyone has any idea what might be happening I'd like to know.