Re: MPI and private methods in octave::load_save_system

[kingcrimson]

> On 16 Feb 2019, at 09:13, address@hidden wrote:
> 
>> 
>> The save_binary_data and read_binary_data functions are public and declared 
>> in ls-oct-binary.h.  If you know that the data on the stream is Octave 
>> binary data using a particular float format, do you really need to read and 
>> write the header, or can you omit that?  If you can omit it, then I don't 
>> think we need to change anything before the release.  If you do need it, 
>> what is it used for?  If it really is necessary, then I would consider 
>> making those functions public for this release.
> 
> I'm not sure whether they are actually needed, I'll look into this this 
> evening.

Indeed, if I specify manually the float format to be native_foat_format, the 
header can be omitted,
with this change the MPI pacakge seems to work :

  
https://github.com/carlodefalco/octave-mpi/commit/81ea87a9a820ddeacceb219203974c95717baadc

I think the reason for not specifying manually the float_format was that MPI is 
expected, in priciple,
to work also on heterogeneous clusters.

I don't think it is a severe limitation if this won't work though (I had never 
tested communication 
between different architectures and I am not sure it ever worked anyway).

So for MPI to work there is no need to do any urgent modification on the stable 
branch before the 5.1 release,
I'll make a relese of the package as soon as Octave 5.1.0 is out.

Still I think it would be useful to have  methods

  read_*_file_header
  write_header

and possibly

  get_file_format 

made public, would it be OK to do that in 5.2?

As a last question  why cannot load_save_system::load_vars (..) be static?

c.