+
+ // Although the filters change, we use this look up table
+ // to set the index of the FFT input buffer, which equivalently
+ // performs the FFT shift operation on every other turn.
+ d_rate_ratio = (int)rintf(d_numchans / d_oversample_rate);
+ d_idxlut = new int[d_numchans];
+ for(unsigned int i = 0; i < d_numchans; i++) {
+ d_idxlut[i] = d_numchans - ((i + d_rate_ratio) % d_numchans) - 1;
+ }
+
+ // Calculate the number of filtering rounds to do to evenly
+ // align the input vectors with the output channels
+ d_output_multiple = 1;
+ while((d_output_multiple * d_rate_ratio) % d_numchans != 0)
+ d_output_multiple++;
+ set_output_multiple(d_output_multiple);