What this is

This code implements a low-pass filter similar to the MCE's (e-mode.phas.ubc.ca/mcewiki) 4-poll readout filter. This should be a very good imitation aside from the use of 8-bit based datatypes (int32_t and int64_t) instead of the tailored accumulators in MCE firmware.

Running the test

To generate the transfer function plots:

make test

To run the timing test (which passes data through numpy C interface):

make test_np python test_np_filt.py

The output from the numpy test is like this:

Testing 12288 channels x 30000.00 samples per second.
Creating 7500 samples of gaussian white noise...
Broadcasting to 12288 channels.
Filtering.
Iter#    Time  Mean-process-time   Gigabytes/s
   4    0.966      0.9657            1.5270
   8    1.804      0.9019            1.6350
  12    2.634      0.8780            1.6795
  16    3.466      0.8664            1.7019
  20    4.291      0.8582            1.7183

The effectiveness is given by the "Mean process time" -- it tells you how long, in seconds, it takes to process 1 second of data. These results (0.9s) show that my old dual-core (ht) AMD can just barely keep up with this data volume.