Calculate accuracy measure based on snaive method

Calculate accuracy measure based on snaive method

accuracy_snaive(ts_info, function_name, length_out)

Arguments

ts_info	list containing training and test part of a time series
function_name	function to calculate the accuracy function, the arguments of this function should be forecast, training and test set of the time series
length_out	number of measures calculated by the function

Value

accuracy measure calculated based on snaive method