| **DONOTDELETE** |
| (Unregistered) |
| 09/10/05 03:42 AM |
Beware JNI! Wrong way. :-)
|
I spend a lot of time checking how to improwe math in Java.
JNI appeared to be the worst choice!!!
1. All the results I got were at first exactly same as authors. However, once I used -server option for jvm all the results were diferent -> Normal Java Math.sin/cos become faster than JNI calls!!! (and jni speed was not so much improved) (jvm 1.4.1 and 1.4.2)
2. Results were even better when I used (in java) simple precalculated array of sinuses (already mentioned in discussion).
Lessons learned (by me):
a) always check yourself !
b) do not forget -server option !!!!!!!!!! (there are others important also (check -XX options)
c) if You really need You can always speed up performance doing changes in Your java code !!! -> all nasty tricks
from game developers, hackers in C/C++ still work in JAVA :-O !!!!
(would You believe that once in a book for C++ I found a trick with bits that allows for faster float to int conversion (faster than normal (float)int_variable statement) -> it works great also with java!).