[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Help-gsl] siman: fixed vs variable configurations

From: John Gehman
Subject: Re: [Help-gsl] siman: fixed vs variable configurations
Date: Fri, 28 Apr 2006 17:15:32 +1000

I think I worked out the problem -- the memcpy functions in siman.c will only copy real data, like my `double rmsd`. For my gsl_vector * values that I'm searching for/optimizing, it copies only the pointer, and therefore the same value being pointed to are adjusted over and over, and a real copy is never set aside as a "best".

Consequently, it would seem that I should use the "variable size" mode of the solver so that I can provide my own copy method. Maybe this is what is meant by "variable size mode" -- variable size meaning dynamically allocated struct components which necessarily used pointers rather than explicit and fixed-size components. I presumed "variable size" meant e.g. varying the number of values searched for (dropping insignificant eigenvalues, for example). I thought my problem was fixed because once set, the structure did not change size at all.

I'm learning, slowly.

Cheers, hope I didn't waste too many people's time

On 27/04/2006, at 5:47 PM, John Gehman wrote:

My gsl_siman_Efunc_t receives the void * argument which refers to my data struct, a component of which is the gsl_vector which holds the (17) values that I want to search for/optimize. The optimum values provide for the best fit to data, and it is the rmsd between the data and fit which I return as "Energy". I also set the "double rmsd" component of the data struct to this same value.


When the minimum temperature is reached, mysystem contains the configuration of sought-values only for the minimal energy of the last temperature run, not the configuration corresponding to the globally minimum value, but the ((struct mysystem *) xp )->rmsd *does* reflect the globally minimum value, as above.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]