Re: [Vxl-users] Reading matrix from mat file

[Amitha P. <am...@th...>]

Hao,

You still didn't provide the error. You also didn't say how you saved 
the .mat file: does it have only one matix? Does it have other data? 
Which version of Matlab? Exact code is useful.

But yes, you would typically use a ifstream to open a file. The follow 
(uncompiled, untested) code should give you the idea:

   vcl_ifstream fin("data.mat");
   if(!fin) { vcl_cerr << "Error opening file\n"; }
   if(!vnl_matlab_read_or_die(fin, A)) { vcl_cerr << "Error parsing 
Matlab file\n"; }

Amitha.



On 7/27/2013 10:16 PM, Hao Wu wrote:
> I'm sorry that I didn't say it clearly. I just save a matrix created 
> by Matlab as a .mat file. Here is my code:
>
> #include <vcl_iostream.h>
> #include <vnl/vnl_matrix.h>
> #include <vcl_fstream.h>
> #include <vcl_istream.h>
> #include <iostream>
> //#include <cstring>
> #include <vnl/vnl_matlab_read.h>
>
> int main()
> {
>   vnl_matrix<double> A;
>   vcl_istream fin;
>   fin.open("data.mat",std::ios::in);
>   vnl_matlab_read_or_die(fin, A);
>   std::cout << "A: " << std::endl << A << std::endl;
>   return 0;
> }
>
> I think I may use the vcl_istream in a wrong way so I cannot read the 
> mat file.
>
> Thanks and regards,
> Hao
>
>
>
>
>
> On Sat, Jul 27, 2013 at 8:19 PM, Amitha Perera <am...@th... 
> <mailto:am...@th...>> wrote:
>
>     Why not cut-n-paste the code, instead of a screenshot?
>
>     What is the error you are seeing when you run the code? How was
>     data.mat created?  You need to provide more detail about your
>     context in order for people to help.
>
>     Amitha.
>
>
>
>     On 7/26/2013 11:38 PM, Hao Wu wrote:
>>     Here is a screenshot of my code, but it seems wrong:
>>     Inline image 1
>>
>>     Can you help me to fix this problem?
>>
>>     Many thanks,
>>     Hao
>>
>>
>>
>>     On Fri, Jul 26, 2013 at 9:13 PM, Hao Wu <hao...@gm...
>>     <mailto:hao...@gm...>> wrote:
>>
>>         Thanks for responding. I found this function but still a
>>         little confused about the usage of it. I am sorry that I am
>>         not very familiar with C++ and VXL. Can you give more details
>>         of how to use it to read matrix from mat file?
>>
>>         Many thanks,
>>         Hao
>>
>>
>>
>>         On Fri, Jul 26, 2013 at 6:45 PM, Amitha Perera
>>         <am...@th... <mailto:am...@th...>> wrote:
>>
>>             There is vnl_matlab_read_or_die() in vnl/vnl_matlab_read.
>>
>>             Amitha.
>>
>>
>>             On 7/26/2013 6:05 PM, Hao Wu wrote:
>>>             Hi all,
>>>
>>>             I want to read a matrix from Matlab '.mat' file. Is
>>>             there anyway in VXL(VNL) which can do this and hopefully
>>>             can return a vnl_matrix type variable?
>>>
>>>             Thanks and best regards,
>>>             Hao
>>>
>>>
>>>
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>>
>>
>>
>
>