Re: Sines and Cosines
On Fri, 21 Mar 2008 22:04:17 -0400, Eric Sosman wrote:
... suggesting Java may be just a hair faster than C, but
that it's "in the noise." (Note, too, that the notions of
"time" used in the two programs are not exactly alike.) I'll
report on results from an AMD laptop later this weekend.
Using your tests on my computer with gcc, I get different results.
kt@lovelace:/tmp$ java TrigTime
nums = 1000000, runs = 10, theta = 0.0, delta = 3.8785094135818516
386 ms, final theta = -0.739085133899082
388 ms, final theta = -0.739085133899082
392 ms, final theta = -0.739085133899082
400 ms, final theta = -0.739085133899082
377 ms, final theta = -0.739085133899082
387 ms, final theta = -0.739085133899082
394 ms, final theta = -0.739085133899082
398 ms, final theta = -0.739085133899082
379 ms, final theta = -0.739085133899082
385 ms, final theta = -0.739085133899082
kt@lovelace:/tmp$ gcc -o test test.c -lm
kt@lovelace:/tmp$ ./test
nums = 1000000, runs = 10, theta = 0, delta = 3.87851
160 ms, final theta = -0.739085
160 ms, final theta = -0.739085
160 ms, final theta = -0.739085
160 ms, final theta = -0.739085
160 ms, final theta = -0.739085
150 ms, final theta = -0.739085
160 ms, final theta = -0.739085
160 ms, final theta = -0.739085
160 ms, final theta = -0.739085
150 ms, final theta = -0.739085
So Java here runs at less than half the speed of C. Oh, and BTW, the
optimization level doesn't matter for this code under gcc.
If I run these with more numbers to get more comparable numbers, I get:
kt@lovelace:/tmp$ ./test 40000000
nums = 40000000, runs = 10, theta = 0, delta = 3.87851
5940 ms, final theta = -0.739085
5920 ms, final theta = -0.739085
5940 ms, final theta = -0.739085
5950 ms, final theta = -0.739085
5910 ms, final theta = -0.739085
5950 ms, final theta = -0.739085
5940 ms, final theta = -0.739085
5920 ms, final theta = -0.739085
5910 ms, final theta = -0.739085
5920 ms, final theta = -0.739085
kt@lovelace:/tmp$ java TrigTime 40000000
nums = 40000000, runs = 10, theta = 0.0, delta = 3.8785094135818516
14650 ms, final theta = -0.739085133899082
14612 ms, final theta = -0.739085133899082
14756 ms, final theta = -0.739085133899082
14628 ms, final theta = -0.739085133899082
14648 ms, final theta = -0.739085133899082
14612 ms, final theta = -0.739085133899082
14623 ms, final theta = -0.739085133899082
14596 ms, final theta = -0.739085133899082
14625 ms, final theta = -0.739085133899082
14592 ms, final theta = -0.739085133899082
The fact that these test end up being so much higher than my tests with
the same number of sine and cosine calculations shows that your test is
probably timing a lot more stuff that we don't care about than mine was.
So, I think I like my test a bit better. ;-)
Now, what is different between our two systems? Operating system wouldn't
really matter that much, would it? Is your's a 64 bit or 32 bit system?
My system is a 1.5 GHz laptop with a T5250 processor and two cores. I'm
running a 32 bit version of Ubuntu Linux. The JVM used above identifies
itself as:
java version "1.6.0_05"
Java(TM) SE Runtime Environment (build 1.6.0_05-b13)
Java HotSpot(TM) Server VM (build 10.0-b19, mixed mode)
--
Kenneth P. Turvey <kt-usenet@squeakydolphin.com>