Re: Performance improvement possible?

Rob,


Rob Biedenharn wrote:
> On Jun 25, 2008, at 8:44 PM, Philip Rhoades wrote:
>> Chuck,
>> 
>> Chuck Remes wrote:
>>> On Jun 25, 2008, at 5:13 PM, Philip Rhoades wrote:
>>>> 
>>>> The change to a single Ruby script simplified the previous
>>>> setup quite markedly but I'm not sure that much more can be
>>>> done with the relatively small script now.  I logged into "ruby
>>>> Talk" on http://codeforpeople.com/ but I couldn't see anywhere
>>>> to post the code.  I can mail the files to anyone who is
>>>> interested in having a look.
>>> Phil, use one of the pastie sites to paste up your code for us to
>>> see. http://pastie.org http://rafb.net
>> 
>> Done - http://pastie.org/222306
>> 
>> I am also rerunning with v1.9 and now that the code is all in one 
>> program it seems to be faster (but still about 3x slower than the 
>> equivalent shell scripts and C/C++ program).
>> 
>> Thanks,
>> 
>> Phil. -- Philip Rhoades
>> 
>> Pricom Pty Limited  (ACN 003 252 275  ABN 91 003 252 275) GPO Box
>> 3411 Sydney NSW    2001 Australia E-mail:  [e-mail]
> 
> OK, even knowing that it started as shell+C, it needs help ;-)


That's why I'm here!


> http://pastie.org/222375
> 
> Except for noticing that the Dir.chdir is still commented out, I
> think that this is equivalent to your original.  Of course, all that
> really means it that I think it produces the same output.  I don't
> have your input files to check (and I'm not really sure I have a clue
> what it is really doing either).


The output seems good.


> If you can directly try this new set, I'd be curious as to the
> relative speed.  A few important notes: * the $darr was never
> referenced so why bother to initialize it


That is for future reference (other stats).


> * the multiple loops in stats06 have been collapsed


Thanks - nice!


> * the various seed* loops now use strings directly


Much nicer!


> * the parameters to statz32000 are strings rather that do somewhat 
> pointless conversions (and sample_sz of 999 would 'overflow' the %02d
>  into "999" anyway).


In the originals I needed the leading zeros as strings for input and
output file name consistency.


> Some potential values won't work as literals (try 08 as an example,
> or 012) since the leading 0 on a literal means octal.


That could be a problem . .


> * the more
> common boolean values are true (rather than TRUE) and false


OK.


> and
> parentheses are not generally needed around the conditional 
> expression of an 'if'


I guess I use them so that they are there for future, more complex 
expressions.

The performance improvement has been fairly dramatic! - the previous 
version using Ruby v1.9 took 3.44 times as long as the original sh/C 
stuff - this version is only takes 1.85 times as long! - an improvement 
of 46%! However I am not sure what the reason is for this improvement - 
though the changes certainly improve the readability and "Rubyness" of 
the code - most of the changes seem cosmetic to me . .

Here is the profile (using v1.8) for pre and post your changes:

Ruby v1.8							
v1.5.1							
%	cumulative	self	self	total			
time	seconds	seconds	calls	ms/call	ms/call		name
59.94	8.44	8.44	1	8440	14080		Object#statz
10.44	9.91	1.47	58318	0.03	0.03		Array#[]
8.1	11.05	1.14	26630	0.04	0.04		String#split
4.05	11.62	0.57	70	8.14	616.14		Range#each
4.05	12.19	0.57	17737	0.03	0.03		String#==
3.05	12.62	0.43	8872	0.05	0.05		IO#gets
2.98	13.04	0.42	8866	0.05	0.05		Fixnum#-
2.34	13.37	0.33	9737	0.03	0.03		Fixnum#+
2.06	13.66	0.29	8916	0.03	0.03		String#to_i
1.92	13.93	0.27	9955	0.03	0.03		Array#[]=
0.36	13.98	0.05	880	0.06	0.06		Fixnum#>
0.21	14.01	0.03	22	1.36	42.27		Object#stats06
0.21	14.04	0.03	274	0.11	0.26		Array#initialize
0.14	14.06	0.02	440	0.05	0.05		Fixnum#==
0.07	14.07	0.01	274	0.04	0.29		Class#new
0.07	14.08	0.01	22	0.45	0.45		IO#puts

Ruby v1.8							
v1.5.2							
%	cumulative	self	self	total			
time	seconds	seconds	calls	ms/call	ms/call		
60.36	7.02	7.02	2	3510	11625		IO#open
9.46	8.12	1.1	29128	0.04	0.04		Array#[]
5.25	8.73	0.61	17737	0.03	0.03		String#==
3.96	9.19	0.46	8871	0.05	0.05		String#split
3.87	9.64	0.45	8872	0.05	0.05		IO#gets
3.87	10.09	0.45	22	20.45	27.73		Integer#times
3.35	10.48	0.39	8800	0.04	0.04		Fixnum#-
3.18	10.85	0.37	9737	0.04	0.04		Fixnum#+
3.1	11.21	0.36	9071	0.04	0.04		Array#[]=
2.75	11.53	0.32	8915	0.04	0.04		String#to_i
0.34	11.57	0.04	880	0.05	0.05		Fixnum#>
0.17	11.59	0.02	115	0.17	0.35		Array#initialize
0.09	11.6	0.01	22	0.45	0.45		Kernel.===
0.09	11.61	0.01	44	0.23	0.23		Array#initialize_copy
0.09	11.62	0.01	440	0.02	0.02		Fixnum#==
0.09	11.63	0.01	44	0.23	0.45		Kernel.dup

Any comments on reasons for the improvement?

Many thanks,

Regards,

Phil.
-- 
Philip Rhoades

Pricom Pty Limited  (ACN 003 252 275  ABN 91 003 252 275)
GPO Box 3411
Sydney NSW	2001
Australia
E-mail:  [e-mail]