convac.py 文件源码

def initLanczos(self, filtOrder):
        self.filtOrder = filtOrder

        if self.filtOrder % 2 != 0:
             raise Exception('Invalid filtOrder: ' + str(self.filtOrder) +
                 ' Must be an even integer.')

        radius = self.filtOrder // 2
        win = np.sinc(np.linspace(-radius, radius, self.filtOrder+1) / float(radius)) # lanczos
        #win = spsig.hamming(self.filtOrder+1) # sinc-hamming

        # this should be automated somehow XXX - idfah
        if self.filtOrder <= 6:
            cutoff = 2*0.570

        elif self.filtOrder <= 8:
            cutoff = 2*0.676

        elif self.filtOrder <= 12:
            cutoff = 2*0.781

        elif self.filtOrder <= 16:
            cutoff = 2*0.836

        elif self.filtOrder <= 32:
            cutoff = 2*0.918

        elif self.filtOrder <= 64:
            cutoff = 2*0.959

        # need to fix for multiple pool sizes XXX - idfah
        cutoff /= float(self.poolSize)

        taps = cutoff * np.linspace(-radius, radius, self.filtOrder+1, dtype=self.dtype)
        impulseResponse = cutoff * np.sinc(taps) * win

        self.filters = []
        nReadoutLayers = 1 if self.nHidden is None else 2
        for ni, no in self.layerDims[:-nReadoutLayers]:
            noEmb = no*(self.filtOrder+1) # no outs after filter embedding

            filtMat = np.zeros(noEmb*2, dtype=self.dtype)
            filtMat[noEmb-1::-no] = impulseResponse

            # filters strided for embedding
            sz = filtMat.itemsize
            filtMat = npst.as_strided(filtMat, (no,noEmb), strides=(sz,sz))[::-1].T
            self.filters.append(filtMat.copy())