Wavelet filters at scale j have both a lower and upper limits for their harmonic support. We already supported the upper limit but this PR adds support for the lower limit. For multi-resolution (which should be used in almost any case) the compute is dominated by the highest scale, where the minimum band limit is half of this.
Given the way S2FFT handles the transform this saves us both a factor of 2 compute and memory. However, this PR only capitalises on the factor 2 compute (as S2FFT only exploits this for acceleration rather than memory efficiency).
Wavelet filters at scale
jhave both a lower and upper limits for their harmonic support. We already supported the upper limit but this PR adds support for the lower limit. For multi-resolution (which should be used in almost any case) the compute is dominated by the highest scale, where the minimum band limit is half of this.Given the way
S2FFThandles the transform this saves us both a factor of 2 compute and memory. However, this PR only capitalises on the factor 2 compute (asS2FFTonly exploits this for acceleration rather than memory efficiency).