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Re: Octave from C++: Saving objects in binary
From: |
Chidambaram Annamalai |
Subject: |
Re: Octave from C++: Saving objects in binary |
Date: |
Mon, 7 Jun 2010 13:46:25 +0530 |
Oops. I didn't even bother to check the Octave C++ API reference for
save_binary_data! I found that the last argument controls the storage
precision.
OCTINTERP_API bool save_binary_data ( std::ostream & os,
const octave_value & tc,
const std::string & name,
const std::string & doc,
bool mark_as_global,
bool save_as_floats
)
Chillu
On 6/7/10, Chidambaram Annamalai <address@hidden> wrote:
> Thanks a lot! This is what I wanted to achieve.
>
> Could you also tell me how I could modify the save_binary_data
> function arguments so that the Matrix A is stored in single precision
> in the binary file? I believe real matrices in octave are by default
> in double precision. I tried float_value (A) but it didn't work.
>
> Thanks,
> Chillu
>
> On 6/7/10, Carlo de Falco <address@hidden> wrote:
>>
>> On 7 Jun 2010, at 07:27, Chidambaram Annamalai wrote:
>>
>>> I need to create large random matrices and perform computations with
>>> them, finally saving the results to a file.
>>>
>>> I had no trouble in creating the matrices in C++ after including the
>>> necessary octave headers like so:
>>>
>>> octave_rand gauss;
>>> gauss.normal_distribution();
>>> std::cout << "Creating gaussian random matrix... ";
>>> Matrix A = gauss.matrix(M, N);
>>>
>>> However, supposing I want to save this matrix A to a file how do I go
>>> about doing that?
>>>
>>> I tried the "feval" method provided here:
>>> http://wiki.octave.org/wiki.pl?CategoryExternal but there's a problem.
>>> The "save" function that I'm interested in, will only take string
>>> arguments and when I supply it with the argument "A" to save to a
>>> binary file it shows the error:
>>>
>>> warning: save: no such variable `A'
>>>
>>> Now how do I tell the "save" function to take the matrix A then? The
>>> problem seems to be that the variable A is not being created in the
>>> memory that is being seen by "save". How do I do that?
>>>
>>> Thanks,
>>> Chillu
>>
>> I'm not sure using feval is the simplest approach,
>> you could use
>>
>> #include <octave/load-save.h>
>> #include <octave/ls-oct-binary.h>
>> std::ofstream os ("A.mat");
>> bool boolvar(false);
>> write_header (os, LS_BINARY);
>> save_binary_data (os, octave_value (A),
>> std::string("A"), std::string(""),
>> boolvar, boolvar);
>> os.close();
>>
>> instead.
>> HTH,
>> c.
>>
>