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

[John Gehman]

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
john

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.