or-tools | Google 's Operations Research tools
kandi X-RAY | or-tools Summary
kandi X-RAY | or-tools Summary
Google Optimization Tools (a.k.a., OR-Tools) is an open-source, fast and portable software suite for solving combinatorial optimization problems. We wrote OR-Tools in C++, but also provide wrappers in Python, C# and Java.
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Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of or-tools
or-tools Key Features
or-tools Examples and Code Snippets
Lines of Code : 7License : Strong Copyleft (CC BY-SA 4.0)
Copyfor f in L_Filas:
for c in L_Columnas:
if tablaOrigD[f+1][c+1]:
s.Add(x[f][c][tablaOrigD[f+1][c+1] - 1] == 1)
[s.Add(x[f][c][tablaOrigD[f+1][c+1] - 1] == 1) for f in L_Filas for c in L_Colum solver = routing.solver()
x2 = solver.IsEqualCstVar(x, 2) # You can use x2 == (x == 2).Var()
y3 = solver.IsEqualCstVar(y, 3)
solver.Add(x2 + y3 >= 1)
Let:
c[i] = some indexed set of coefficients
x[i] = some indexed variable
Desire:
minimax (c[i]*x[i])
Introduce:
my_max = real valued variable, non-indexed
Make constraint
for i in I:
my_max >= c[i]*x[i]
from ortools.sat.python import cp_model
# DATA
capacity = 6
money = 20
beers = [
{"name":"Beer1", "type":"Lager", "price":3.50, "score":4.1},
{"name":"Beer2", "type":"Porter", "price":4.90, "score":4.5},
{"name":"Beer3", "typ def __mul__(self, arg):
if isinstance(arg, numbers.Integral):
if arg == 1:
return self
elif arg == 0:
return 0
cp_model_helper.AssertIsInt64(arg)
r# Team Assignment
import pyomo.environ as pyo
### DATA
sectors = {
"1A": 80,
"1B": 20,
"2A": 10,
"3A": 50,
"3B": 20,
"3C": 110
}
teams = {
"TeamA":20,
"TeamB":15,
"TeamC":100,import collections
from ortools.linear_solver import pywraplp
def set_cover(ss):
solver = pywraplp.Solver.CreateSolver("SCIP")
solver.Objective().SetMinimization()
constraints = collections.defaultdict(
lambda: solver# Vehicles list
trucks = [1, 3, 6, 7, 9, 10]
vans = [4, 5]
pickups = [2, 8]
# location list with a tuple (location, truck, van pickup)
locations = [
(1, True, True, True), # C-01
(2, True, True, False), # C-02
(3, True, False, Falsefrom ortools.sat.python import cp_model
model = cp_model.CpModel()
a = model.NewIntVar(0, 10, "")
model.Add(11 <= a <= 30)
solver = cp_model.CpSolver()
solver.Solve(model)
print(solver.StatusName())
hours num_shifts = len(shifts)
num_drivers = ceil(float(num_shifts) / working_time)
working_time = 22
break_time = 2
break_interval = [8, 16]
Community Discussions
Trending Discussions on or-tools
QUESTION
I have a problem I am trying to optimize with about 1 million variables and 10 million constraints. CP-SAT takes a long time to find a feasible solution. I was reading the output and I see a few things I don't understand.
- It tells me that I need to increase symmetry to at least 3. Looking at this link (and assuming it is relevant to the latest version of CP-SAT and using Python) it says
// Whether we try to automatically detect the symmetries in a model and // exploit them. Currently, at level 1 we detect them in presolve and try // to fix Booleans. At level 2, we also do some form of dynamic symmetry // breaking during search.
But it doesn't say anything about symmetry at 3 or above. What does it do if you set it to 3?
- I tried setting symmetry to 3 and now that message has gone but I am left with
[Symmetry] GraphSymmetryFinder error: During the initial refinement.
Is this something I should try to resolve, and if so how?
- There is also a line like:
[Probing] deterministic_time: 1.00001 (limit: 1) wall_time: 1.21766 (Aborted 10197/201810)
Is that something to worry about and can I increase limit to make the probing complete rather than abort? limit isn't one of the parameters in solver.parameters it seems. Is limit setting a cap on the number of seconds Probing can run for? What is happening in this probing step?
ANSWER
Answered 2022-Apr-09 at 09:42Symmetry detection and probing are optional, potentially costly, phases during presolve.
Symmetry detection is nice, but does not yet support all constraints. So it can fails. The solver will silently ignore this failure.
For probing, the best way to improve perf is to use multiple workers (8 or more). Continuous probing is enabled if you have more that 12 workers. Of course, it is best if your computer has that many cores.
QUESTION
as part of my code, I'm trying to get the total number of non-zero contracts that my solver is trying to solve so I can add a constraint and put a limit on it. since or-tools doesn't support if statements directly, I decided to use the .OnlyEnforceIf() solution that I found on numerous websites. this is the code I came up with:
ANSWER
Answered 2022-Mar-23 at 16:48The API you use is only for CP-SAT.
QUESTION
ANSWER
Answered 2022-Mar-20 at 16:37This is how find_element method works.
It returns the first matching element on the DOM it finds.
So in case you are passing it locator matching several elements on the page the first matching element on the DOM will be returned.
In case you want to get all the elements matching that locator find_elements method should be used instead.
So, in case you want to get all the texts in elements matching div[class='isMainTerm'] a[class='dictLink'] CSS Selector instead of
QUESTION
I'm trying to solve a VRP problem allowing dropping nodes through penalties and multiple depots.
Code works fine with penalties and vehicles starting and ending at the same depots:
...ANSWER
Answered 2022-Feb-07 at 10:59With custom start and ends, you should use Routing.Start(vehicle_index) and Routing.End(vehicle_index) to get the index of these nodes.
QUESTION
I am trying to use custom routing in anylogic. For routing optimization, I am using Google OR-Tools and I have imported all the necessary packages and dependencies in the model properties section.
I am a rookie after doing some research I made several changes in the protocol buffer .jar file as mentioned in GitHub but still I am facing the same error.
.
If I try to remove the protocol buffer dependency from the model properties again I end up getting the same error.
Thanks in advance.
...ANSWER
Answered 2022-Jan-31 at 11:13For the protobuf version I STRONGLY recommend you to look at the version specified in the maven pom.xml template since the version should match the version use in the C++ side of the library.
You can find it here https://github.com/google/or-tools/tree/stable/ortools/java
note: use the tag related to your or-tools version usually we try to be in sync with the last protobuf release available when we release a new or-tools version.
note: this is a mandatory requirement in python to avoid any strange behaviour and I expect the same weird undefined behaviour if you also don't follow this..
QUESTION
I am wondering the syntax for logical constraints in Google OR-Tools. I have a nurse scheduling project I have done in CPLEX that I am translating over to Google OR-Tools. I have come across the documentation for channeling constraints in Google OR-Tools, but I am confused. Can you help me understand how I would implement this CPLEX logical constraint in Google OR-Tools? I have an attempt, but it is not working as intended :(
Context:
working_assignment_vars_long[r,h,i] is a binary decision variable that denotes whether nurse i in role r is working at the 15-minute interval h (i.e. 1:15PM).
lunch_break_assignment_vars_long[r,h,i] is a binary decision variable that denotes whether nurse i in role r is on break at the 15-minute interval h (i.e. 1:15PM).
simple_break_assignment_vars_long[r,h,i] is a binary decision variable that denotes whether nurse i in role r is on break at 15-minute interval h.
Thus, this constraint in CPLEX is saying that if a given nurse is working 31 or less 15-minute intervals, then they should have 0 lunch breaks and 1 simple break.
CPLEX logical constraint:
...ANSWER
Answered 2022-Jan-22 at 00:11In the official documentation it is documented how to do an If-Then-Else expression.
You aren't constraining b.Not():
QUESTION
I have an optimization problem where I have a list of lists of "BoolVar" objects. So something like this:
...ANSWER
Answered 2022-Jan-02 at 09:50OnlyEnforceIfis just an implication. You need to add the reverse direction.You should stay in the Boolean world:
QUESTION
I am using Google OR-Tools to solve a maintenance scheduling problem. I have five machines which are all initially broken. I need to schedule tasks for two technicians to fix the machines to minimize the total lost output. Each technicial can fix any of the machines. However, the time taken to fix each machine is different (but known for each machine beforehand). The output from each machine is the same. Thus, the optimal solution is to do the quickest tasks (machine fixes) first and so as many machines are up and running as soon as possible. (This is a toy problem to get me started on something more complex.)
I've hacked around the job shop problem to solve this for one technician (see working python script below) but I am stuck trying to apply it to two technicians as I can't work out how to handle the no overlap condition between two sets of technicians' tasks.
...ANSWER
Answered 2021-Dec-27 at 10:42You could model it by creating an array of variables technicianForTask[task] which indicate which technician is doing each task. Then add no-overlap constraints for each pair of intervals, but only enforced if the technician is the same for both the tasks.
I don't have a working Python installation, but the equivalent c# code would look like this:
QUESTION
I created a sample test.lp file as follows:
ANSWER
Answered 2021-Dec-02 at 12:20If you change
QUESTION
I am trying to create a vehicle routing problem for multi-drivers with pickup and drop-off locations. The starting point for each driver is their current location and the ending point would be anywhere they end.
The input to my algorithm is a series of lot/long locations. The final output would be the best(shortest) route decided for the driver starting from his location and ending at any location. My actual final output is a route that starts at the driver location and ends at the driver location.
My problem is how can I create the distance matrix while nullifying the end location (the distance from the end node to any other node would be zero).
These are the functions that convert the lat/long locations to distance matrix >>
...ANSWER
Answered 2021-Nov-28 at 11:00Apparently, it is as simple as it is answered in the other question. I added a row of zeros and an additional zero at the start of every row after creating the distance matrix > this will tell the algorithm that the distance between the point at index zero and any other point is 0. And I set my end point data["ends"] = 0.
So in my case the distance matrix would look like this >>
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install or-tools
Ubuntu 18.04 LTS and up (64-bit);
Apple macOS Mojave with Xcode 9.x (64-bit);
Microsoft Windows with Visual Studio 2019 (64-bit).
We provide a Make based build.Please check the Make build instructions.
We provide a CMake based build.Please check the CMake build instructions.
We provide a Bazel based build.Please check the Bazel build instructions.
The best way to learn how to use OR-Tools is to follow the tutorials in our developer guide:. If you want to learn from code examples, take a look at the examples in the examples directory.
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