Code review request for 6908131 Pure Java implementations of StrictMath.floor(double) &StrictMath.ceil(double)

[Jeff Hain]

Dmitry,

From your bench, I see FloorCeil methods get in trouble
with 64 bits architecture, but I never ran anything on 64 bits yet.

I ran your bench on my laptop:
- DELL inspiron 9400, with (two) Genuine Intel T2300 @ 1.666GHz.
- java.runtime.version=1.6.0_11-b03
- java.class.version=50.0
- os.name=Windows XP
- os.arch=x86
- os.version=5.1

I added two patterns:
- pattern3 ("common" case (for doubles) of non-integer values) {
            0.1, -0.1,
        1e4+0.1, -1e4-0.1,
        1e8+0.1, -1e8-0.1,
       1e12+0.1, -1e12-0.1,
   (1L<<52)/1.1, -(1L<<52)/1.1}
- pattern4 (case of integer values) {
            0.0, -0.0,
            1e4, -1e4,
            1e8, -1e8,
       (1L<<52), -(1L<<52),
       (1L<<60), -(1L<<60)}

I also added test of the pure Java StrictMath class (which is the one you ran
as "StrictMath" in your bench?) posted on this subject: "StrictMath_JD".

Here is what I got:
 
-----------------------------------------
- CLIENT
-----------------------------------------
 
pattern 1:
empty                took       4,42 nsec  
Math.ceil            took      63,77 nsec  
Math.floor           took      67,55 nsec  
StrictMath.ceil      took      64,20 nsec  
StrictMath.floor     took      68,76 nsec  
StrictMath_JD.ceil   took      52,58 nsec  
StrictMath_JD.floor  took      53,57 nsec  
FloorCeil.ceil       took      24,31 nsec  
FloorCeil.floor      took      18,37 nsec  
 
pattern 2:
empty                took       4,50 nsec 
Math.ceil            took     110,95 nsec 
Math.floor           took     110,42 nsec 
StrictMath.ceil      took     111,38 nsec 
StrictMath.floor     took     110,97 nsec 
StrictMath_JD.ceil   took      48,95 nsec 
StrictMath_JD.floor  took      49,38 nsec 
FloorCeil.ceil       took      23,29 nsec 
FloorCeil.floor      took      20,81 nsec 
 
pattern 3:
empty                took       4,39 nsec 
Math.ceil            took     111,72 nsec 
Math.floor           took     114,48 nsec 
StrictMath.ceil      took     113,68 nsec 
StrictMath.floor     took     114,32 nsec 
StrictMath_JD.ceil   took      60,23 nsec 
StrictMath_JD..floor  took      60,13 nsec 
FloorCeil.ceil       took      27,11 nsec 
FloorCeil.floor      took      23,77 nsec 
 
pattern 4:
empty                took       4,38 nsec 
Math.ceil            took     113,49 nsec 
Math.floor           took     113,34 nsec 
StrictMath.ceil      took     110,35 nsec 
StrictMath.floor     took     112,95 nsec 
StrictMath_JD.ceil   took      43,69 nsec 
StrictMath_JD.floor  took      44,28 nsec 
FloorCeil.ceil       took      22,09 nsec 
FloorCeil.floor      took      18,71 nsec 
 
-----------------------------------------
- SERVER
-----------------------------------------
 
pattern 1:
empty                took       2,40 nsec  
Math.ceil            took      64,61 nsec  
Math.floor           took      65,14 nsec  
StrictMath.ceil      took      63,93 nsec  
StrictMath.floor     took      65,99 nsec  
StrictMath_JD.ceil   took      37,52 nsec  
StrictMath_JD.floor  took      39,77 nsec  
FloorCeil.ceil       took      21,36 nsec  
FloorCeil.floor      took      13,96 nsec  
 
pattern 2:
empty                took       2,23 nsec 
Math.ceil            took     112,42 nsec 
Math.floor           took     110,88 nsec 
StrictMath.ceil      took     112,05 nsec 
StrictMath.floor     took     113,54 nsec 
StrictMath_JD.ceil   took      33,98 nsec 
StrictMath_JD.floor  took      33,97 nsec 
FloorCeil.ceil       took      22,09 nsec 
FloorCeil.floor      took      16,75 nsec 
 
pattern 3:
empty                took       2,19 nsec 
Math.ceil            took     113,67 nsec 
Math.floor           took     113,53 nsec 
StrictMath.ceil      took     114,46 nsec 
StrictMath.floor     took     115,02 nsec 
StrictMath_JD.ceil   took      44,19 nsec 
StrictMath_JD.floor  took      43,57 nsec 
FloorCeil.ceil       took      25,57 nsec 
FloorCeil.floor      took      20,95 nsec 
 
pattern 4:
empty                took       2,45 nsec 
Math.ceil            took     108,56 nsec 
Math.floor           took     112,96 nsec 
StrictMath.ceil      took     109,43 nsec 
StrictMath.floor     took     113,14 nsec 
StrictMath_JD.ceil   took      30,18 nsec 
StrictMath_JD..floor  took      31,07 nsec 
FloorCeil.ceil       took      18,11 nsec 
FloorCeil.floor      took      15,91 nsec 
 
-----------------------------------------

Jeff

PS : The ceil and floor I posted here are an extract of a FastMath class (I already
     see some people in this mailing list invoking the gods against me while having
     a heart attack at the hearing of this class name) I did, and put on source
     forge (I already told about it in this list few months ago): maybe some of
     you might want to take a look at it (it's called "FastMath", but not ALL of
     its treatments are wrong...). 



      
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