A naive downsampling implementation because I simply have too much data.

downsample.js.coffee

# A naive downsample implementation.
#
# arguments:
#
# * `data`: the array of data you want to sample
# * `sampleLength`: the number of samples you want
#
# returns a two element array, where the 1st
# element, k, is the sampling period (ie, sample
# every kth element) and the 2nd element is an
# array of all samples.
#
downsample: (data, sampleLength) ->
  # compute k, where we want every kth value in the data array
  k = Math.floor(data.length / sampleLength)

  # just return the values if we want all of them
  return [1, data] if k <= 1

  # return an array with every nth value
  [k, _.filter(data, (v, i) -> i % k == 0)]