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I have a simple network that has several routes from start to end. Vehicles from a transporter fleet will carry agents from the left conveyor to the right conveyor using the moveByTransporter block. What are some syntax i can use to refer to paths/nodes on the network?
Also, what is a sample code line of how i can check the number of vehicles on a specific path?
This is my sample network and idea of trying how to make a new routing instead of just the shortest path (the path i want to follow is via the yellow highlighted one)
The moveTo block will take the route with the shortest distance. If the agent's speed is the same across all choices, then the shortest distance will also be the fastest time.
In the past, I have used Dijkstra's algorithm and manually routed my agents from a to b, then b to c, etc. This way, I could use travel times instead of just distances. This also opens up the possibility of considering congestion by applying a penalty to some segments if there are too many other agents on them. You can also pick a route, but then when you get to the next node, re-calculate the rest of the route for updated congestion considerations.
This is all custom, and I would not recommend it for simple problems. You would be better off to look at other alternatives (assume constant speeds or consider the pedestrian library with walls, etc, depending on your problem).
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Edit: The solution was that the serviceRate was too high for the amount of arriving trucks.
In my Anylogic model, I have a population of terminals (5) and a population of trucks (100). The trucks visit the terminals, which are a queueing model for them. The terminals have a number of gates (e.g., 7) that can all service 1 truck at a time (service time is based on a uniform distribution). If all the gates are busy, the other trucks have to wait in a (FIFO) queue in front of the terminal.
I want to measure the time trucks are standing within the queues before the terminals (without the service time). How can I create these terminal processes best within my Anylogic model?
I tried using a service block (the first processes in the picture), but I think that gives all the time and not only the time within the queue. I also tried a queue and delay block (below), to be able to measure the queue time. However, the distribution of the time measurement is not working as I get no distribution but just 1 (very small) number, as can be seen in the lowest picture. Same if I measure the time within the service or delay block... Does any body know how to let this work? Thanks!
You delay capacity is numberOfGates. It means if that value is 5, then 5 trucks will move into delay block at the same time. Other arrived trucks will wait in the queue if delay.size()=5. There is nothing wrong in this, you should check if your model really works as intended.
The agents would move into delay block immediately if you selected the maximum capacity option in the delay block.
Also instead of timeMeasureStart/End, use your own assignments. That is, inside the delay, on enter type agent.waitStart = time(); and upon leaving type yourHistogramData.add(time()-agent.waitStart);
It turns out that the service rate was too high for the amount of trucks I send to the terminal.
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I need lots of cables of different small sizes (under 100 meters) and cables are only sold in lenghts of 100 meters.
So, to optimize my purchase, I would like a code where I can input the lengths of all pieces of cables that I need. The code will combine my inputs under the constraint the sum is under 100, while minimizing the total number of 100m-length cables that I need to buy.
If anyone could help with a code in VBA, Matlab or Python I would be very grateful.
This is known as a bin-packing problem, and it's actually very difficult (computationally speaking) to find the optimal solution.
However, it is a problem that is practically useful to solve (as you have seen for yourself) and so there are several approaches that seek to find an approximate solution--one that is "good enough" without guaranteeing that it's the best possible solution. I did a quick search and found this course website, which has some examples that may help you out.
If you are looking for an exact solution, you can ask the related question "will I be able to fit the cables I need into N 100-meter cables?". This feasibility problem can be expressed as a "binary program", which is a special case of a "mixed-integer linear program", for which MATLAB has a solver called intlinprog (requires the optimization toolbox).
I'm sorry that I don't have any code to solve your problem, but I hope that this at least gives you some keywords to help you find more resources!
I believe this is like the cutting stock problem. There are some very good methods to solve this. Here is an implementation and some background. It is not too difficult to write an Excel front-end for this (see here).
If you google for "cutting stock problem" you will find lots of references.
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i have a question on speed up application built by MATLAB software, i need to know the affect of using vectorization and parallel computation on speed up the application ? and if there is better method than both previous way in such case ? thanks
The first thing you need to do when your MATLAB code runs too slow is to run it in the profiler. In recent versions of MATLAB, this can by done by pressing the "Run and Time" button on the main toolbar. This way, you will now which functions and which lines in these function take up the most time. Once you know this, you may do one of the following, depending on your circumstances and the nature of the particular piece of code:
Think if your algorithm is the most optimal one in terms of O() complexity.
Try turning loops into vector operations. The efficacy of this has declined in recent versions of MATLAB because of improvements in how loops are executed.
If you have a multi-core CPU try using the parallel computing toolbox. If your code parallelizes well, you will get a sped up nearly equal to the number of cores.
If you have an nVidia GPU try using the GPU support. You can get a speed-up by a factor of 10 or more with some problems, but not all problems are amicable to this sort of optimization.
If everything else fails, you may outsource the slowest piece of your code to a low level language like C. See here for how to do this. You could then use low-level profiling tools like Intel vTune to get the absolute maximum speed from the low-level code.
If it is still too slow, you may need to buy an FPGA. See here for a brief tutorial.
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It is said, "If a negative edge cycle is reachable from the source than the algorithm returns false".
What does this "reachable from source indicates"?
Look at the following image:
Can you give me some example in which this algorithm will return false if there exist a negative edge cycle reachable from source.
Note: I am new to algorithms.
What that means is that if there exists a cycle that has a total weight that is negative, then the algorithm cannot give an answer because repeatedly following the cycle "reduces" the weight of the path. I don't see any negative weight cycles (by inspection) in the graph you show, so the stated limitation shouldn't be a concern in your case.
Edit: "reachable from source" means that the negative weight cycle is only a concern if it is reachable - meaning that a path from the specified source to some node in the negative weight cycle exists - from the start or source node. Bellman Ford finds the shortest path from a distinguished node to all nodes reachable from that node. Does that make sense?
When the algorithm is used to find shortest paths, the existence of negative cycles is a problem, preventing the algorithm from finding a correct answer. However, since it terminates upon finding a negative cycle, the Bellman-Ford algorithm can be used for applications in which this is the target to be sought - for example in cycle-cancelling techniques in network flow analysis.
Please refer this link:- http://evlm.stuba.sk/~partner2/DBfiles/Optimization/Dynamical%20optimization/Optimization_EN_Ford-Belman_algorithm.pdf
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Basically I have some hourly and daily data like
Day 1
Hours,Measure
(1,21)
(2,22)
(3,27)
(4,24)
Day 2
hours,measure
(1,23)
(2,26)
(3,29)
(4,20)
Now I want to find outliers in the data by considering hourly variations and as well as the daily variations using bivariate analysis...which includes hourly and measure...
So which is the best clustering algorithm is more suited to find outlier considering this scenario?
.
one 'good' advice (:P) I can give you is that (based on my experience) it is NOT a good idea to treat time similar to spatial features. So beware of solutions that do this. You probably can start with searching the literature in outlier detection for time-series data.
You really should use a different repesentation for your data.
Why don't you use an actual outlier detection method, if you want to detect outliers?
Other than that, just read through some literature. k-means for example is known to have problems with outliers. DBSCAN on the other hand is designed to be used on data with "Noise" (the N in DBSCAN), which essentially are outliers.
Still, the way you are representing your data will make none of these work very well.
You should use time series based outlier detection method because of the nature of your data (it has its own seasonality, trend, autocorrelation etc.). Time series based outliers are of different kinds (AO, IO etc.) and it's kind of complicated but there are applications which make it easy to implement.
Download the latest build of R from http://cran.r-project.org/. Install the packages "forecast" & "TSA".
Use the auto.arima function of forecast package to derive the best model fit for your data amd pass on those variables along with your data to detectAO & detectIO of TSA functions. These functions will pop up any outlier which is present in the data with their time indexes.
R is also easy to integrate with other applications or just simply run a batch job ....Hope that helps...