Re: [Gretl-devel] function calling and value copies
Am 22.01.2011 20:59, schrieb Allin Cottrell:
On 01/22/2011 01:27 PM, Riccardo (Jack) Lucchetti wrote:
> On Sat, 22 Jan 2011, Riccardo (Jack) Lucchetti wrote:
>
>> On Sat, 22 Jan 2011, Sven Schreiber wrote:
>>
>>> The funny thing is that the first version of the code that copies
>>> the
>>> generated number to the variable 'temp' is about 50% slower than the
>>> version without such copying!
>>
>> Confirmed here. I'll look into this.
>
> From some preliminary analysis, the difference seems to come from
> the fact that assigning the result to a variable avoids calling
> is_gretl_function_call() at line 2369 of lib/src/interact.c; this,
> in turn, saves calls to sscanf(), which is quite expensive. Mumble
> mumble.
If you replace
muniform(1,1)
with
eval muniform(1,1)
then it runs faster than the version with copying. The sooner
gretl can figure out what you want, the faster.
Hm, thanks but this actually makes things worse:
gretl-Version 1.9.3cvs
Aktuelle Sitzung: 2011-01-22 22:50
? set echo off
with variable copying.
this iteration run time: 10.710000
---------------------
no variable copying.
this iteration run time: 83.500000
---------------------
Apart from that I found only implicit hints to 'eval' in the manual or
in the command reference:
"eval cmult(z1,z2)"
"eval abs((parm - oxparm) ./ oxparm)"
And as a minor thing, 'eval' is also not syntax-colored.
thanks,
sven