Init Variables

initi_variables.py

# Count Machines
machines_count = 1 + max(task[0] for job in jobs_data for task in job)
print("{:,} machines".format(machines_count))
all_machines = range(machines_count)

# Computes horizon dynamically as the sum of all durations.
horizon = sum(task[1] for job in jobs_data for task in job)
print("Total Time using Naive Solution: {} min".format(horizon))

# Named tuple to store information about created variables
task_type = collections.namedtuple('task_type', 'start end interval')
# Named tuple to manipulate solution information.
assigned_task_type = collections.namedtuple('assigned_task_type',
                                            'start job index duration')

# Creates job intervals and add to the corresponding machine lists.
all_tasks = {}
machine_to_intervals = collections.defaultdict(list)

# Create Machine Sequences
for job_id, job in enumerate(jobs_data):
    for task_id, task in enumerate(job):
        machine = task[0]
        duration = task[1]
        suffix = '_%i_%i' % (job_id, task_id)
        start_var = model.NewIntVar(0, horizon, 'start' + suffix)
        end_var = model.NewIntVar(0, horizon, 'end' + suffix)
        interval_var = model.NewIntervalVar(start_var, duration, end_var,
                                            'interval' + suffix)
        all_tasks[job_id, task_id] = task_type(start=start_var,
                                               end=end_var,
                                               interval=interval_var)
        machine_to_intervals[machine].append(interval_var)