def ordering_cost(ordering_cost, demand_quantity, order_quantity):
"""
Calculate the ordering cost - the total cost of placing, receiving,
and processing orders needed to fulfill a given amount of demand.
Parameters
----------
ordering_cost : int or float
Cost per order, in dollars
demand_quantity : int
The amount of demand, in units
order_quantity : int
The number of units purchased per order, in units
Returns
-------
ordering_cost: float
"""
Validate.required(ordering_cost, "ordering_cost")
Validate.non_negative(ordering_cost, "ordering_cost")
Validate.required(demand_quantity, "demand_quantity")
Validate.non_negative(demand_quantity, "demand_quantity")
Validate.required(order_quantity, "order_quantity")
Validate.positive(order_quantity, "order_quantity")
return ordering_cost * (demand_quantity / order_quantity)
def optimal_cycle_time(raw_costs, demand):
"""
Calculate optimal cycle time (T*) given raw costs and demand.
Parameters
----------
raw_costs : RawCosts
A `RawCosts` object, containing a set of raw cost values
demand : Demand
A `Demand` object, containing demand quantity and time frame
Returns
-------
optimal_cycle_time: float
"""
Validate.required(raw_costs, "raw_costs")
Validate.required(demand, "demand")
Validate.positive(demand.quantity, "demand.quantity")
Validate.positive(raw_costs.holding_cost, "raw_costs.holding_cost")
numerator = 2 * raw_costs.ordering_cost
denominator = demand.quantity * raw_costs.holding_cost
return math.sqrt(numerator / denominator)
