| Re: Compiling file with many functions: huge performance difference between IDL and IDLDE [message #38665 is a reply to message #38531] |
Wed, 17 March 2004 14:02   |
andrew.cool
Messages: 47
Registered: July 2003
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Member |
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Sidney Cadot <sidney@jigsaw.nl> wrote in message news:<1079516867.600179@euler.servers.luna.net>...
> Hi all,
>
> For a system we're making, a rather big IDL file is generated containing
> well over 12,000 function definitions, accompanied by a selector
> function (see below for a rationale).
>
> What we're seeing is that in command-line IDL, this works like a charm:
> compilation of the file takes about 4--5 seconds on a reasonably fast
> machine, which is acceptable.
>
> However, when this file is compiled from within IDLDE, this takes well
> over three minutes-- rougly a factor 60 increase(!)
>
> Does anybody know what causes this, and perhaps a solution?
>
> We tried pre-compiling the functions using a SAV file; this yields a
> significant increase both in IDL (cmd line version): 3 sec, and IDLDE
> (used time down to 87 seconds), but the relative difference is still
> quite puzzling.
>
> Best regards,
>
> Sidney Cadot
> Science and Technology Corp., The Netherlands
>
>
>
>
> P.S. the reason we're doing this is that we need to implement a
> string-based map with optiomal performance, like this:
>
> FUNCTION f_tom
> RETURN, 123
> END
>
> FUNCTION f_dick
> RETURN, 456
> END
>
> FUNCTION f_harry
> RETURN, 789
> END
>
> FUNCTION f, name
> CATCH, error_status
> IF error_status EQ 0 THEN RETURN, -1
> RETURN, call_function("f_" + name)
> END
OK, me dumb bunny - me no know what a string based map is.
But based on your example above, how about this?
map_array = Strarr(12000,2)
map_array(0,1) = string(indgen(12000),form='(i5.5)')
map_array(5000,0) ='dick'
t = Systime(1)
found_index = Where(map_array(*,0) EQ 'dick')
print,'Time taken = ',Systime(1) - t,' seconds'
print,'Found Index = ',found_index
ret_value = map_array(found_index,1)
print,'Returned Value = ',ret_value
Now on my PC, Time taken = 0.00000000 seconds,
which I'd call pretty close to "optiomal".
Do you really need 12000 function definitions?
Andrew Cool
DSTO, Adelaide, South Australia
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