Re: the accuracy of MPB

No no no.
  The data are genarated automatically by run fuction, eg run-zeven.
 I can not use "print" inside the run fuctions.
 how to use (print "the eigenfrequencies:" freqs "\n") to instead of run-zeven? I mean let the MPB print the freqs at each k-points for each band.
  
 Does this "Print" is a kinds of band-func? In which I can use (run-zeven band-func ...) to obtain all the freqs at each k-points for each band.
  
 Thanks for your reply.
  
 Best wishes
 Ran
  
  ------------------ Original ------------------
  From:  "Steven G. Johnson"<[email protected]>;
 Date:  Wed, Nov 11, 2009 09:54 AM
 To:  "mpb-discuss"<[email protected]>; 
 
 Subject:  Re: [MPB-discuss] the accuracy of MPB

  
On Nov 10, 2009, at 5:54 AM, ryanhao wrote:
>     the data generated by MPB or MEEP is mostly in float format,  
> which is only 6 numbers after the point. Eg:0.248182
>     but sometime, I need more accuracy in data, Eg: for Differential.
>     I have seen one of your explaination in the earlier email:
You can print out to double precision by just using a print statement  
in Scheme, e.g.

(print "the eigenfrequencies:" freqs "\n")

If you want to do computations with these numbers, you can also do  
them directly within your control file.  If you want to compute  
derivatives, it might be a good idea to use the (deriv ...) function  
provided by libctl, which uses Ridder's method to compute numerical  
derivatives accurately by Richardson extrapolation.

The HDF5 files are output in double precision by default as well.

Steven

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