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Protect agains infinite loop when plotting tiny ranges #130

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Protect agains infinite loop when plotting tiny ranges #130

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2 changes: 1 addition & 1 deletion chart/Graphics/Rendering/Chart/Axis/Floating.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -108,7 +108,7 @@ scaledAxis lap rs@(minV,maxV) ps0 = makeAxis' realToFrac realToFrac
ps = filter isValidNumber ps0
range [] = (0,1)
range _ | minV == maxV = if minV==0 then (-1,1) else
let d = abs (minV * 0.01) in (minV-d,maxV+d)
let d = max 1e-300 (abs (minV * 0.01)) in (minV-d,maxV+d)
| otherwise = rs
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@ghorn ghorn Jun 19, 2016

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I'm not actually sure if this is the correct behavior. It seems to give me a range of (-1e-300, 1e-300) when rs = (0, 0) and the freeze came back. Could you check it for me?

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@Shimuuar Shimuuar Jun 27, 2016

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I think 1e-300 is bad choice. Smallest normalized number 2.2250738585072014e-308 is 8 orders of magnitude away and underflow doesn't happen even for 1e-321. It's probably better to check whether maxV+d and minV-d are equal to maxV/minV.

range _   | minV == maxV = case minV of
             0                            -> (-1,1)
             _ | lo /= minV && hi /= maxV -> (lo,hi)
               | otherwise                -> (minV/2,maxV*2)
          | otherwise    = rs
d  = abs (minV * 0.01)
lo = minV - d
hi = maxV + d

labelvs = map fromRational $ steps (fromIntegral (_la_nLabels lap)) r
tickvs = map fromRational $ steps (fromIntegral (_la_nTicks lap))
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