Function assesses whether the inputs correspond to the requirements for scoring sample-based forecasts.
check_input_sample(observed, predicted)
Returns TRUE if the check was successful and a string with an error message otherwise.
Input to be checked. Should be a numeric vector with the observed values of size n.
Input to be checked. Should be a numeric nxN matrix of
predictive samples, n (number of rows) being the number of data points and
N (number of columns) the number of samples per forecast.
If observed
is just a single number, then predicted values can just be a
vector of size N.