nb_series_per_chunk = toInteger(nb_series_per_chunk, function(x) x>=K1)
min_series_per_chunk = toInteger(K1, function(x) x>=K1 && x<=nb_series_per_chunk)
ncores_tasks = toInteger(ncores_tasks, function(x) x>=1)
nb_series_per_chunk = toInteger(nb_series_per_chunk, function(x) x>=K1)
min_series_per_chunk = toInteger(K1, function(x) x>=K1 && x<=nb_series_per_chunk)
ncores_tasks = toInteger(ncores_tasks, function(x) x>=1)