equivalent of octave filter

[Marco]

Hi, I am trying to create the equivalent of the octave/matlab "filter" function in my project.
Until now I have achieved to translate y = filter(b,1,x), but now I also need the second vector that is returned from the filter function, i.e. [y,z] = filter(b,1,x).
Do you know I can get z?

This is how I have achieved y = filter(b,1,x):

/**
 * @brief equivalent of matlab function filter(b,1,x)
 */
template <class T1, class T2>
static arma::Col<T2> firFilter(const arma::Col<T1>& b, const arma::Col<T2>& x) {
        sp::FIR_filt<T2,T1,T2> fir_filt;
        fir_filt.set_coeffs(b);

        unsigned int inputSize = x.size();
        arma::Col<T2> y(inputSize);  // Output sig

        for(unsigned int n=0;n<x.size();n++)
        {
            y[n] = fir_filt(x[n]);
        }

        return y;
    }

Edit: after I get z I have to use it as the fourth argument of the filter, i.e. [y2,z2] = filter(b,1,x,z). Is this supported?

[Claes Rolen]

Hi, thanks for using SigPack. I guess that the reason for you to add the internal states (z) from the filter is that you will call this function at different times and that it will have a "warm" start with the previous filter state. Actually this is already handled in SigPack since the filter itself is a class and the internal state will be encapsulated within the class between calls of filter() or the filter operator. BR Claes