Estimates the tau-th quantile from the unsorted data array. The tau-th quantile is the data value where the cumulative distribution function crosses tau. The quantile definition can be specified to be compatible with an existing system. WARNING: Works inplace and can thus causes the data array to be reordered.

Estimates the tau-th quantile from the unsorted data array. The tau-th quantile is the data value where the cumulative distribution function crosses tau. The quantile defintion can be specified by 4 parameters a, b, c and d, consistent with Mathematica. WARNING: Works inplace and can thus causes the data array to be reordered.