updated the histogram lib to 0.1.2 on the playground.
There are three experimental functions: PMF, CDF and VAL.
PMF is quite similar to frequency, but uses a value as parameter. (no knowledge of buckets is needed)
CDF gives the sum of frequencies <= value.
VAL is CDF inverted.
As the Arduino typical uses a small number of buckets (<20) these functions are quite coarse or even inaccurate (read useless).
Linear interpolation within the buckets will improve the accuracy but it is unknown to what extend. If the average value of every bucket is available the interpolation can be better than just linear interpolation. However this additional code and storage will increase the footprint and complexity of the lib..
side effect is that the changes caused the lib to grow 224 bytes compared to 0.1.3
so possibly a smaller unsafer version of the lib (SmallHisto?) is still appreciated ???