A few "consts" have been added. The dates are now considered to be positive which allows comparison operators to be optimized: converting 1 year of hourly data with data_converter got almost 30% faster. Moreover, when looking for resampling window, two extra checks have been added to quickly see if the start and end point are even in the input vector. This reduces data read miss (because we start by reading vecM[0]) and skips browsing through the whole vector if we are in a large data gap. On the same 1 year data set with one large gap for one parameter, the gain is of almost 20%. Overall, these two optimizations lead to almost a doubling of the speed with data_converter... Soon we'll be so fast that we will get the data before it is even measured!