Question

Possible Duplicate:
C programming division

I am trying to convert values into the Mel Filter but, every time I output the result, it is always “0” even though it is a double. Should it be a float? Here is an article on the equation: http://en.wikipedia.org/wiki/Mel_scale

Here is the functions:

double MFCC::mel_filter(int val)
{
     double tmp;
     tmp = 2595 * log10(1 + val / 700);
     cout << tmp << endl;
     return tmp;
    }

    vector<double> MFCC::mel_frame(int size)
    {
    vector<double> mel_Frame;
    for(int i=1; (i < size); i++)
    {
          this->mel_filter(i);
    }

    return mel_Frame;
    }

In main, I will pass values such as.. (1, 2, 3, 4, 5, 6, 7 ……)

And if “1” was entered then the equation would be:

m = 2595 * log10(1 + 1 / 700) = 1.6

Any help or suggestions?

Answer 1

Your problem is at

log10(1 + val / 700)

That’s using an integer division instead of a real division. Try with

log10(1 + val / 700.0)