lasp/beamforming/fft.pyx

include "config.pxi"

# setTracerLevel(0)

cdef extern from "fft.h":
    ctypedef struct c_Fft "Fft"
    c_Fft* Fft_alloc(us nfft,us nchannels)
    void Fft_free(c_Fft*)
    void Fft_fft(c_Fft*,dmat * timedate,cmat * res) nogil
    us Fft_nchannels(c_Fft*)
    us Fft_nfft(c_Fft*)

cdef class Fft:
    cdef:
        c_Fft* _fft

    def __cinit__(self, us nfft,us nchannels):
        self._fft = Fft_alloc(nfft,nchannels)
        if self._fft == NULL:
            raise RuntimeError('Fft allocation failed')

    def __dealloc__(self):
        if self._fft!=NULL:
            Fft_free(self._fft)

    def fft(self,d[::1,:] timedata):

        cdef us nfft = Fft_nfft(self._fft)
        cdef us nchannels = Fft_nchannels(self._fft)
        assert timedata.shape[0] ==nfft
        assert timedata.shape[1] == nchannels
        
        result = np.empty((nfft//2+1,
                           nchannels),
                           dtype=NUMPY_COMPLEX_TYPE,order='F')
        # result[:,:] = np.nan+1j*np.nan
        cdef c[::1,:] result_view = result
        cdef cmat r = cmat_foreign(result.shape[0],
                                   result.shape[1],
                                   &result_view[0,0])
        cdef dmat t = dmat_foreign(timedata.shape[0],
                                   timedata.shape[1],
                                   &timedata[0,0])

        Fft_fft(self._fft,&t,&r)

        dmat_free(&t)
        cmat_free(&r)

        return result


cdef extern from "window.h":
    ctypedef enum WindowType:
        Hann = 0
        Hamming = 1
        Blackman = 2
        Rectangular = 3

cdef extern from "ps.h":
    ctypedef struct c_PowerSpectra "PowerSpectra"
    c_PowerSpectra* PowerSpectra_alloc(const us nfft,
                                       const us nchannels,
                                       const WindowType wt)
    void PowerSpectra_compute(const c_PowerSpectra* ps,
                             const dmat * timedata,
                             cmat * result)
    

    void PowerSpectra_free(c_PowerSpectra*)

cdef class PowerSpectra:
    cdef:
        c_PowerSpectra* _ps

    def __cinit__(self, us nfft,us nchannels):
        self._ps = PowerSpectra_alloc(nfft,nchannels,Rectangular)
        if self._ps == NULL:
            raise RuntimeError('PowerSpectra allocation failed')

    def compute(self,d[::1,:] timedata):
        cdef:
            us nchannels = timedata.shape[1]
            us nfft = timedata.shape[0]
            int rv
            dmat td
            cmat result_mat
        td = dmat_foreign(nfft,
                          nchannels,
                          &timedata[0,0])

        # The array here is created in such a way that the strides
        # increase with increasing dimension. This is required for
        # interoperability with the C-code, that stores all
        # cross-spectra in a 2D matrix, where the first axis is the
        # frequency axis, and the second axis corresponds to a certain
        # cross-spectrum, as C_ij(f) = result[freq,i+j*nchannels]

        result = np.empty((nfft//2+1,nchannels,nchannels),
                          dtype = NUMPY_COMPLEX_TYPE,
                          order='F')
        cdef c[::1,:,:] result_view = result

        result_mat = cmat_foreign(nfft//2+1,
                                  nchannels*nchannels,
                                  &result_view[0,0,0])

        PowerSpectra_compute(self._ps,&td,&result_mat)

        dmat_free(&td)
        cmat_free(&result_mat)

        return result


    def __dealloc__(self):
        if self._ps != NULL:
            PowerSpectra_free(self._ps)


cdef extern from "aps.h":
    ctypedef struct c_AvPowerSpectra "AvPowerSpectra"
    c_AvPowerSpectra* AvPowerSpectra_alloc(const us nfft,
                                           const us nchannels,
                                           d overlap_percentage,
                                           const WindowType wt)

    cmat* AvPowerSpectra_addTimeData(const c_AvPowerSpectra* ps,
                                     const dmat * timedata)
    

    void AvPowerSpectra_free(c_AvPowerSpectra*)

            
cdef class AvPowerSpectra:
    cdef:
        c_AvPowerSpectra* aps
        us nfft, nchannels

    def __cinit__(self,us nfft,us nchannels,d overlap_percentage):
        self.aps = AvPowerSpectra_alloc(nfft,
                                        nchannels,
                                        overlap_percentage,
                                        Rectangular)
        self.nchannels = nchannels
        self.nfft = nfft

        if self.aps == NULL:
            raise RuntimeError('AvPowerSpectra allocation failed')

    def __dealloc__(self):
        if self.aps:
            AvPowerSpectra_free(self.aps)
        
    def addTimeData(self,d[::1,:] timedata):
        """!
        Adds time data, returns current result
        """
        cdef:
            us nsamples = timedata.shape[0]
            us nchannels = timedata.shape[1]
            dmat td
            cmat* result_ptr

        if nsamples < self.nfft:
            raise RuntimeError('Number of samples should be > nfft')
        if nchannels != self.nchannels:
            raise RuntimeError('Invalid number of channels')            

        td = dmat_foreign(nsamples,
                          nchannels,
                          &timedata[0,0])

        result_ptr = AvPowerSpectra_addTimeData(self.aps,
                                                &td)

        # The array here is created in such a way that the strides
        # increase with increasing dimension. This is required for
        # interoperability with the C-code, that stores all
        # cross-spectra in a 2D matrix, where the first axis is the
        # frequency axis, and the second axis corresponds to a certain
        # cross-spectrum, as C_ij(f) = result[freq,i+j*nchannels]

        result = np.empty((self.nfft//2+1,nchannels,nchannels),
                          dtype = NUMPY_COMPLEX_TYPE,
                          order='F')
        cdef c[::1,:,:] result_view = result
        cdef cmat res = cmat_foreign(self.nfft//2+1,
                                     nchannels*nchannels,
                                     &result_view[0,0,0])
        # Copy result
        cmat_copy(&res,result_ptr)

        cmat_free(&res)
        dmat_free(&td)


        return result