[mlpack-git] [mlpack/mlpack] Wrong number of mapping while Loading (#658)

[stereomatchingkiss]

@keonkim I think the behavior is correct, let us use non-tranpose case to discuss the behavior

codes : 

```
try{
        arma::mat data;
        data::DatasetInfo info;
        bool const fatal = true;
        bool const transpose = false;
        data::Load("simple00.csv", data, info, fatal, transpose);
        std::cout << data << endl;
        std::cout<<"dimensions == "<<info.Dimensionality()<<std::endl;

        Log::Info << "dataset info: " << endl;
        for (size_t i = 0; i < data.n_rows; ++i)
        {
            std::cout << info.NumMappings(i) << " mappings in dimension "
                      << i << "." << endl;
        }
    }catch(std::exception const &ex){
        std::cerr<<ex.what()<<std::endl;
    }
```

Before we transpose, mlpack treat every columns as an example, every row as a dimension
every dimension represent one type of feature(height, weight, color, etc).

After we know how mlpack treat the data, everything are simple

input data

a,    b,        c
b, 102, 1002
c, 103, 1003
d, 104, 1004

What would you expect?Since every row represent to a feature, we know that a,b,c at row 0 should map to different numeric value.Because Every row represent to different features, we know that a,b,c,d at column 0 should map to one numeric value. What are the output?

output : 

 0.000000e+00   1.0000e+00   2.0000e+00
 0.000000e+00   1.0200e+02   1.0020e+03
 0.000000e+00   1.0300e+02   1.0030e+03
 0.000000e+00   1.0400e+02   1.0040e+03

As expected, right?
3 mappings in dimension 0.
1 mappings in dimension 1.
1 mappings in dimension 2.
1 mappings in dimension 3.

So, why it looks like that?



a,    b,        c
b, 102, 1002
c, 103, 1003
d, 104, 1004



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