In general, I've found that the combination of 'par' and 'sum' with 'take'
triggers long translation times, because take is O(n) in the number of
graph nodes generated, so the overall behavior is O(n^2).
I was trying to implement a hilbert transformer (512 length FIR) with the
definition of 'fir' in filter.lib and getting compilations that timed out
at 500s (I didn't have the patience to wait 60 min). I made a new
definition of fir that avoids sum and take (and has some other special case
rules) and now get translation times around 0.5 sec. Looking at the
'light' case, both generate the same C++ code.
I put a copy of the full file at http://www.ai.sri.com/ajh/hilbert.dsp
// light length = 33
//process = firx(hilbert_light_coeffs); //real 0m0.033s user 0m0.016s sys
0m0.013s
//process = fir(hilbert_light_coeffs); //real 0m0.068s user 0m0.048s sys
0m0.016s
// medium length = 257
//process = firx(hilbert_medium_coeffs); //real 0m0.116s user 0m0.096s sys
0m0.017s
//process = fir(hilbert_medium_coeffs); // abort at 500s
// heavy length = 513
process = firx(hilbert_heavy_coeffs); //real 0m0.516s user 0m0.492s sys
0m0.022s
//process = fir(hilbert_heavy_coeffs); // abort at 500s
firx(coeffs) = fir_cell(coeffs):>_ with
{
fir_cell(0) = !;
fir_cell(float(0)) = fir_cell(0);
fir_cell(1) = _;
fir_cell(float(1)) = fir_cell(1);
fir_cell((0,(coeffs))) = (mem:fir_cell(coeffs));
fir_cell((float(0),(coeffs))) = fir_cell((0,coeffs));
fir_cell((c,0)) = fir_cell(c);
fir_cell((c,float(0))) = fir_cell((c,0));
fir_cell((c,(coeffs))) = _<:fir_cell(c),(mem:fir_cell(coeffs));
fir_cell(c) = *(c);
};
Best...
Aaron Heller ([email protected])
Menlo Park, CA US
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