Related tasks on different resources

[sv136]

Hello,

Is it possible to make the tasks related by precedence, to work on different resources? Something like that from your example, but vice versa

S += green_paint < green_post
# green_post will use the same resources as green_paint if there is an overlap in resource requirement
green_post += green_paint*[Alice,Bob]

Thnx!

[timnon]

There is a change in the add_capacities branch which allows the follows:

S += green_paint < green_post*Alice

This would imply that green_paint is scheduled before green_post if green_post is schedule on Alice (also works with the list). The * can be interpreted in general as an if.

Is this your requirement? The branch isnt merged yet, but it is basically complete, just didnt merge yet.

[sv136]

Looking at the axample, I think no. I want implement the following rules

if green_paint is scheduled on Alice then green_post should be scheduled on Bob
if green_paint is scheduled on Bob then green_post should be scheduled on Alice
green_paint < green_post

I think your code doesn't provide it.

[timnon]

here is some snippet that does that:

#! /usr/bin/env python
import sys
sys.path.append('../src')
from pyschedule import Scenario, Task, Resource, solvers, plotters, alt

horizon = 10

S = Scenario('Scenario',horizon=horizon)
green_paint = S.Task('green_paint',completion_time_cost=1)
green_post = S.Task('green_post',completion_time_cost=2)

person = S.Resources('person_',num=2)

green_paint += alt(person)
green_post += alt(person)

green_post += green_paint*person

solvers.mip.solve(S, msg=1)
plotters.matplotlib.plot(S, fig_size=(10, 5))

So if green_paint is scheduled on any of the person, then green_post as well.

[sv136]

It looks like initial task where both tasks are scheduled on the same resource, and moreover green_post is shceduling before green_paint. In terms of your last example I want the following

if green_paint is scheduled on person_0 then green_post should be scheduled on person_1
if green_paint is scheduled on person_1 then green_post should be scheduled on person_0
green_paint < green_post

Your code sends both tasks to the same resource.

[timnon]

Ok, got it wrong, use a capacity constraint:

from pyschedule import Scenario, Task, Resource, solvers, plotters, alt

horizon = 10

S = Scenario('Scenario',horizon=horizon)
green_paint = S.Task('green_paint',completion_time_cost=1,green=1)
green_post = S.Task('green_post',completion_time_cost=2,green=1)

person = S.Resources('person',num=2)

green_paint += alt(person)
green_post += alt(person)

S += person[0]['green'] <= 1
S += person[1]['green'] <= 1

S += green_paint < green_post

solvers.mip.solve(S, msg=1)
plotters.matplotlib.plot(S, fig_size=(10, 5))

[sv136]

It looks like sports-scheduling example (link), but It generates an error:
TypeError: unorderable types: NoneType() <= int()

My artificial example (isnpired by your answer) generates 'no solution':

N = 2  # NUM of Tasks
K = 2  # NUM of Legs
M = 2  # NUM of Machines
minTimeTask,maxTimeTask=2,5 # Task Execution time
TaskOfTask = []
Machines = [S.Resource('Machine{0}'.format(m)) for m in range(M)]

for n in range(N):
    subTasks = []
    for k in range(K):
        TaksName = "Task{0}_{1}".format(n+1,k+1)        
        Task = S.Task(TaksName,randint(minTimeTask,maxTimeTask), completion_time_cost=1, green = 1 )
        Task += alt( R for R in Machines )        
        subTasks.append(Task)    
    TaskOfTask.append(subTasks)
for M in Machines:
    S += M['green']<=1
        
S.use_makespan_objective()
solvers.mip.solve(S,msg=1)

What am I doing wrong?

[timnon]

The following works for me? Please upgrade to the newest version 0.2.29, maybe there is some old bug. I also did some simplification regarding the definiton of the machines. The S += M['green']<=1 is too hard, i dont get a solution, so changed just for testing. Note that i define the Machines as a list and apply the ['green'] <= 1 to all of them at once.

from pyschedule import Scenario, Task, Resource, solvers, plotters, alt
from random import randint

horizon = 50
S = Scenario('Scenario',horizon=horizon)

N = 2  # NUM of Tasks
K = 2  # NUM of Legs
M = 2  # NUM of Machines
minTimeTask,maxTimeTask=2,5 # Task Execution time
TaskOfTask = []
Machines = S.Resources('Machine',num=M)

for n in range(N):
    subTasks = []
    for k in range(K):
        TaskName = "Task{0}_{1}".format(n+1,k+1)
        Task = S.Task(TaskName,randint(minTimeTask,maxTimeTask), completion_time_cost=1, green= 1)
        Task += alt(Machines)
        subTasks.append(Task)
    TaskOfTask.append(subTasks)

S += Machines['green'] <= 3

if solvers.mip.solve(S, msg=1):
	plotters.matplotlib.plot(S, fig_size=(10, 5))
else:
	print('no solution exists')