Opps. Link doesn't work. Do you mean the OCTAVE/MATLAB "filter" command? If you limit that to FIR coefficients then that's equivalent literally to a convolution operation which we already have. (that FIR filtering is the convolution function I have to de-bunk every year in my DSP class because in teaching nothing is filtered in realtime so an FIR filter is sold literally as a convolution operation, however the FIR filter does a convolution as any other filter but it performs it with the help of a delay line which is implemented usually as a ring buffer).
Perhaps before we talk about different things. Can we all agree on the definition of an FIR filter: https://en.wikipedia.org/wiki/Finite_impulse_response it takes one sample in and spits one out by using a delay line. Usually implemented as a ring buffer. In C that can be done very elegantly with pointer gymnastics: https://github.com/berndporr/fir1 Arne, do you have an efficient way of doing that in JAVA? That would be nice. Best, /Bernd On 24/10/16 09:28, Arne Ploese wrote: > Am Samstag, den 22.10.2016, 23:25 +0100 schrieb Bernd Porr: > > (...) > >> I'm not too crazy about proper FIR filters in JAVA because even in >> C++ >> they are just too slow and one would need to write them as JNI calls >> to >> C to make them run fast enough (for example a 50Hz notch for ECG at >> 1kHz >> requires 500taps at a bandwidth of 4Hz -- in theory!). Not sure how >> excited people here are about C/JNI calls. However the FIR filter >> _design_ = creating an impulse response is useful for a-causal >> offline >> computation using the convolution operation (but the 1D convolution >> is >> already implemented isn't it?). > If the Just In Time compiler of the runtime kicks in, it will go > fast... > You can avoid wrapper code (get|set) and access the fields directly - > ist will improve speed even more. Here is an example of a java > filtering (converted form the signalprocessing package of octave) I did > a couple of years ago: > https://sourceforge.net/projects/dsp4 > > (...) > > Arne > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > -- www: http://www.berndporr.me.uk/ http://www.linux-usb-daq.co.uk/ http://www.imdb.com/name/nm3293421/ Mobile: +44 (0)7840 340069 Work: +44 (0)141 330 5237 University of Glasgow School of Engineering Rankine Building, Oakfield Avenue, Glasgow, G12 8LT --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
