[GRASS-dev] GRASS inefficiency and FFTW

[stefano de paoli]

Hi Glynn

> The decision to switch from the NR code to FFTW
> was "provoked" by
> the licensing issue, but it could realistically have
> occurred for
> other reasons.
> 
> The licensing issue just happens to
> have been the
> trigger.

You are probably right. But there is something missing
in your argument IMHO.

Think to be a policeman which is trying to discover
who is the murder of a person.
Actually you can think that a person could
realistically die for many reasons (because of oldage,
under a motorcar, illness), but for you as policeman
it does matter who was the murder and had triggered
such a person. 

Your point of view is correct, but it is that of a
programmer.

I'm a sociologist and it does matter who triggered the
NR. Becasue this case shows how the license choice has
affected the ways GRASS has evolved. 
Moreover it shows that the GRASS Dev. Team had to face
a contingent problem related to the GPL choice and had
to find a solution to the problem, which is what I'm
interested into. 

We can draw a comparison with v.in.dwg. Why it doesn't
exist a GPL compatible library like Opendwg?
I don't know why, the reasons could be many. But what
matters is that the GPL has triggered v.in.dwg which
cannot be distributed with GRASS.
So the GPL affects what is GRASS. And developers have
to face contingent problems and to solve them.

Another case should be that of LZW VS DEFLATE.

Many humanistic studies on licensing simply neglect
that developers have to solve problems because of 
licenses. Free Software is usually thought in an
idealistic way,probably due to Eric Raymond idea of
Bazaar. 


> IOW, classifying cases of "inertia-related
> inefficiency" according to
> what triggered the underlying changes isn't a
> meaningful exercise,
> IMHO.

In fact there is something wrong in the way I'm trying
to transmit the NR-FFT example. That's why I've been
invited to write to the GRASS-DEV list.

It is true that the clssification of "inertia-related
inefficiendy" is not very meaningful.
Maybe it is wrong to use the term efficiency in an
absolute way. Really now I Know that the FFTW solution
is much more better than the NR for many reasons
(which I didn't figure it out before this thread)

What is menaningful is to learn from the GRASS NR
case, something for our understanding of Free Software
in general: that the idealistic idea of Bazzar is
simply wrong in many cases.
Open Source advocates usually says that the solution
to a problem in the "Open Source model" would be the
best possible solution.

Observing the GRASS and Numerical Recipes case
(altough it may be a minor example) I concluded that
the claims about the "best possible solution" is
simply wrong.

The solution to a problem could be a "quick and dirty"
solution related for example to the limited amount of
time that a restricted group of developers can
dedicate to the problem.

Probably my mistake is to think that this solution is
necessarily related to the "freedom" of software. 
While many GRASS developers have pointed out that
other issue are far more important, such as the amount
of developer effort required to make the change .

 
> > I still support the conclusion that there is an
> > inefficiency which heavily dependes on the GPL
> choice.
> 
> The decision to switch FFT implementations due to
> licensing was
> certainly a factor. The decision to only expend the
> bare minimum of
> effort to get the FFTW version working had nothing
> to do with
> licensing, though.

Thanks I got this point quite well now.

Stefano


	

	
		
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