simmer | Discrete-Event Simulation for R
kandi X-RAY | simmer Summary
kandi X-RAY | simmer Summary
simmer is a process-oriented and trajectory-based Discrete-Event Simulation (DES) package for R. Designed to be a generic framework like SimPy or SimJulia, it leverages the power of Rcpp to boost the performance and turning DES in R feasible. As a noteworthy characteristic, simmer exploits the concept of trajectory: a common path in the simulation model for entities of the same type. It is pretty flexible and simple to use, and leverages the chaining/piping workflow introduced by the magrittr package.
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simmer Key Features
simmer Examples and Code Snippets
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Trending Discussions on simmer
QUESTION
I'm making an async call to an API and then setting the data I get back to my state variable all inside a useEffect function. Out side of that function I then destructure the values into variables and the render them to the screen.
The issue is that the instructions variable is still undefined at time of render and I'm a bit confused why when the others render fine.
(The instructions variable is also an array of objects)
Top Component
...ANSWER
Answered 2022-Feb-28 at 15:56The useEffect hook is first executed after the first initial render, also the request is asynchronous meaning there will be at least one render before receiving the network response and the data object being populated with the value for instructions.
This is expected behaviour, you can choose to defer rendering part of the component until the data is fetch, or provide some loading state.
QUESTION
I am a React noob. I am using Material UI and Material UI icons and React to create a title with a forward and back button, so the user can scroll through the pictures on display. When I press the forward button, the picture in "index 2" shows nothing. When I press the back button, the picture in "index 0" is blank (weird, right?). This seems like a super weird bug in my mind. Is there something I am missing here? It is making no sense to me.
Here is my code (as you can see I'm still editing things, so I still have the default text from when I grabbed this from Material UI).
...ANSWER
Answered 2022-Jan-24 at 02:29In your handler functions, the array index may go out of bound. So you should modify your handler functions like below:
QUESTION
I am making a simple app where it displays some recipes and you can go into an individual 'recipe screen' which shows an image/ingredients and instructions for making the recipe. However I am now trying to make a button which returns you to the recipe list. The button works however the recipe screen and the recipe list which I am returning to seem to overlap, therefore I need to figure out how to clear the recipe screen before moving to the recipe list screen. However, for some reason the clear_canvas() or clear_screen() functions do not work. What should i do instead in order to clear the kivy screen?
This is an image of the overlapping screens:
Python code:
...ANSWER
Answered 2021-Dec-20 at 14:42Since you add stuff to the RecipeWindow using the on_enter() method, just add an on_leave() method to clear it:
QUESTION
I did a simulation with simmer and I got an event log. The start and end of an activity are represented as time units. they look as follows:
...ANSWER
Answered 2021-Oct-02 at 17:38This is to help you getting started. I am not a DES/simmer expert. But what I understand is that the activity log gives you start and end times (in your simulation) of specific activities.
I am not fully sure how "simulation units" of 2700 account for a week. But you may calculate your "simulation time step" based on this.
For a start, I assume the given activity start and end "units" are minutes.
reproducible data for activity log
QUESTION
I'm learning SQL and trying to join several mock Hotel tables and make a simple query that shows a guest's concatenated name and the number of reservations they've made.
No matter how I try to restructure my query I keep getting one of two errors.
If I try this way:
...ANSWER
Answered 2021-Sep-27 at 16:57This is why I really dislike people using literal strings for aliases; the only place this works is in the SELECT. GROUP BY 'Guest Name' doesn't mean "Group by the column aliased as 'Guest Name'" it means "Group by the literal string 'Guest Name'", which, unsurprisingly doesn't make any sense.
Even if you had used a better delimit identifier for your alias, either T-SQL's Brackets ([]) or ANSI-SQL's double quotes ("),you still wouldn't be able to do what you did as you can't reference a column by it's alias in the GROUP BY (for example GROUP BY [Guest Name] would produce the error "Invalid column name 'Guest Name'"). This is due to the Logical Processing Order of the SELECT statement and that the GROUP BY is processed several steps before the SELECT (steps 5 and 8 respectively), and so the alias has no context within the GROUP BY.
Instead you either need to GROUP BY the expression itself, or by the columns contained in the expression. I would personally use the latter here.
QUESTION
C:\Users\Yeap\Documents\react sitio web\my-app\node_modules\react-scripts\scripts\start.js:19
throw err;
^
[Error: ENOENT: no such file or directory, stat 'C:\Users\All Users'] {
errno: -4058,
code: 'ENOENT',
syscall: 'stat',
path: 'C:\\Users\\All Users'
}
ANSWER
Answered 2021-Sep-23 at 22:22You installed @material-ui packages but import from @mui package. That wont work.
The packages you need to install is:
QUESTION
I am building a simmer simulation for the delivery of vaccines via drone. Pseudocode up to the simulation part is:
- Generate N "demand points" in a geography, representing locations needing vaccines. Make into a dataframe. Add arrival times as a dataframe column. Add prioritization column - first come, first served.
- Use kmeans clustering to find K drone stations locations, across the geography
- Generate a N x K matrix representing travel time from each drone station, to each demand point
In the simulation, vaccine deliveries are arrivals, and drones are resources (server capacity 1, infinite queue capacity). I want the simulation to use this resource selection logic:
- When an arrival occurs, determine which drone(s) are available. Of those, select the drone that has the shortest travel time as determined by the travel time matrix.
- If all drones are currently utilized, new arrivals get put into a common queue. Whenever any drone becomes available, arrivals in the common queue take priority, with the oldest arrival in the queue taking first priority. This may mean that a vaccine is NOT delivered from the closest drone station.
- Once an arrival
seize_selectedthe selected drone,timeoutfor the travel time, thenrelease_selectedthat drone.
I'm trying to adapt the logic from Use routing logic when dispatching resources with simmer package (or an alternative) but is not working as anticipated.
Any help is appreciated. The really tricky part here to me, is putting the arrivals into a common queue, THEN selecting the fastest-available drone.
My current simulation code is:
ANSWER
Answered 2021-Jul-29 at 13:44You need an additional resource on top of that with capacity equal to the number of drones. That's your common queue. If you need your oldest arrival first, that's LIFO. Setting the priority value according to a counter function would achieve exactly that (or, if you set that priority in the source data frame, that works too). Putting everything together:
QUESTION
I am exploring SimPy to model patient flows through care processes. In a mock model, patients can either receive treatment or die. Obviously, these are competing risks, and patients should not be able to receive treatment after dying. However, I am very new to SimPy and I have yet to discover how to model a sink so that these deceased patients cannot continue through the simulation.
I am more familiar with the simmer package in R, in which you can branch() the model structure and specify which branch of the model structure is a dead end. Is there similar functionality in SimPy? Or are there other elegant options?
To illustrate what I mean, below is the mock model:
...ANSWER
Answered 2021-May-11 at 14:55There are two main types of simulation The classic entity flow where stations have all the logic and the entity has very little and the stations decide the fate of the entity. Agent base where the entity/agent has all the code and decides it's own fate.
The classic example for entity flow is manufacturing production lines where the stations/machines decide what to do to the entity and where to send it (branch to) next. Your R code sounds like it uses this paradigm
Your example is more agent like where the entity/patient controls its own behavior.
To fix this you just need to add a "state" attribute to the class to track if the patient is live or dead. Then check the patient's state in your while loop
see below:
QUESTION
I am a beginner in Flutter and I am stuck at converting my API fetched data to my custom model. I am using an API that provides me with this data:
...ANSWER
Answered 2021-May-08 at 18:49You can get all keys and then check each one against your condition.
QUESTION
I'm trying to create a simulation model that describes traffic near the motorway gates.
I have added the resources
...ANSWER
Answered 2021-Apr-30 at 12:41As it turns out i was looking for a proper use of function "log_()" and "get_selected()"
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