18 lines
892 B
Matlab
18 lines
892 B
Matlab
% cursed
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% lmao
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% basically - I take pairs of adjacent values on the vector `x` and add them
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% together. These sums are then checked against both members of the pair,
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% and if either member is *larger* than the sum, that indicates a sign change
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% since one of the values acted as a subtractor.
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% "Glue" is added in the comparison stage, to skew ONLY on cases where
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% we are comparing zero to zero (origin case). Its really a rounding error otherwise. lol
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% The front is padded w/ a zero.
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function ret = switchsign(x)
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sum_check = x(1:end-1) + x(2:end);
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ret = [0, ( abs(sum_check) < abs(x(1:end-1)+1e-7) ) | ( abs(sum_check) < abs(x(2:end)+1e-7) ) ];
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end
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% <-.01> works here (this is insane), but technically has an
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% error: calling `switchsign([-1 2 1 0 1 -3])` (the example i
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% gave) returns `[0 1 0 1 1 1]` rather than `[0 1 0 0 0 1]`.
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% not that that really matters. sorry...
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