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I am trying to develop a time table generator software for my college. Obviously it requires a great deal of constraint satisfaction i.e. I need to satisfy a lot of rules in order to generate a bunch of time tables where classes do not clash. After doing some research and reading this article, I feel I need to use some AI in it. Now, I am a complete newbie to AI. Can anyone tell me which algorithm will work best in my case?
The simplest algorithm that you can use for this problem is genetic algorithm (or any other evolutionary algorithm). Solving this problem using GA is very simple but yet effective. There are lots of papers and codes that have used this approach for this problem.
If you have few rules and constraints, you may want to use exact straightforward techniques like backtracking with CSP heuristics to speed it up, but if there are lots of classes and constraints, I suggest Genetic Algorithm.
Well, not a trivial task indeed. Problems like this one are VERY hard to solve.
Here I can recommend you two things:
Use an existing CSP/COP solver and describe your constraints in its language. These solvers are very good, fast and tuned, being developed for years.
Educate yourself in the area of Discrete Optimization (there was a course at coursera.org with the same name which was great). Only after you grasp the basics of how these things work can you try to write your own solver. But let you be warned! Discrete optimization is pain and suffering :-).
This is by no means a suitable place to just tell you how CSP/COP works. It is a very broad and difficult field.
I wish you good luck!
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I'm a software major student and my first programming book was "Clean Code" by Robert C Martin. So I know the importance of clean code and trying to apply it to my code.
However, if I try to implement the algorithm I learned from university, it just messed up. I can solve the problem through my hands but it's hard to do with a computer. And even I code a class of algorithm through c++, it normally violates clean code principles(The most severe one is so many parameters of method.)
Recently, to improve my skills, I'm trying online judges but it doesn't help my code clean much...
Could you advise me about this according to your experience? I really want to make my code clean and also well designed. I'll sooo appreciate you!
+I have a code of algorithm for knapsack problem made by backtracking method. If you want, I can post it but probably messy and hard to understand... T_T
The problem with code tests is that they are often contrived and do not reflect real-world examples.
Often when I have designed programs the requirements have been set out in a way that reflects the existing paper-based systems that they intend to computerise. This is a fair place to start for conveying the "problem domain" however it doesn't go quite far enough. To take it to the next step, you need to be able to analyse what's needed for a system with use cases, scenarios and "stories". From then you can identify at a top level how your system should work.
At the same time, you also need to work "bottom up" by writing small pieces of code, each to achieve a single task.
By breaking down the problem in this fashion, it enables you to focus on single parts of the system at both high-level and low-level. By identifying actors, use-cases and scenarios, you then have some reasonable idea of how to structure your code and delegate appropriately.
I can recommend a book which tremendously helped me rethink how to approach the problem solving part - "Design Patterns Explained": https://www.amazon.co.uk/Design-Patterns-Explained-Perspective-Object-Oriented/dp/0321247140/ref=sr_1_1
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I have two functions performing same process but with different techniques and I need to know on a large scale which technique is faster than the other of maybe in the future will be more techniques available. So my question is, how can I do that in c++ specially? Is there a specific method and header to be used to perform this task?
More details:
For example the isLargest() uses three parameters and it has two versions, one uses a nested if technique and the other uses initializers and less if statements. So if I need to know which one is faster, how can I do that?
Try your code in the real world and measure
There is a tool called a profiler that is meant to solve this problem. Broadly speaking, there are two kinds (note: some are a mix between the two):
Sampling profilers.
Instrumenting profilers.
It's worth learning about what each does and their pros/cons, but if you don't know what to use go with a sampling profiler.
There are many sampling profilers, but support depends on your platform. If you're on Windows, Visual Studio comes with a really nice sampling profiler and I recommend you start there!
If you go down this route, it's important to make sure you use your functions as you would "for real" when you're profiling them, as there are many subtle factors that can affect the result.
An alternative
If you don't want to try your code running in a real program, perhaps if you're just trying to understand general characteristics of the function, there are libraries to help you do this such as Google Benchmark.
Benchmarking code can be surprisingly difficult to get right, so I would strongly recommend using existing benchmarking tools where like Google Benchmark wherever possible.
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New to C++ and stuck on how to start coding this problem which is an Ecology question at first to start a cell with plants antelopes and tigers. Based on initial population, birth rates, food supply, dying off and migration into other cells (once 1 cell is discovered then can expand more). Did some tests on paper to see that plants are going to need a Cap because plants multiply more than antelopes can eat them. I dont really know how to start this if anyone can give me a starting point then that will be grateful.
Thank you.
I sounds like you're trying to build an individual, agent-based, or microscale model: this being subsets of the more general topic of discrete event simulation. Looking into those topics and reading some of the literature and books around them would be a good start.
One way to get started conceptually might be to play with SimPy. Once you think you understand how its pieces fit together and how to build a model, you'll be in a better position to move to a higher-performance language, like C++, where you'll need to build more of the components yourself.
You should also learn how to program. Having to ask a question as general as you are at the beginning of this endeavour should give you pause: people have devoted careers figuring out how to do this the right way. That said: C++ is a decent choice of language because you'll need to run your model not just once, but tens of thousands of times, in order to get an idea of how variable your results are. Remembering that the number of interactions between variables grows exponentially in the number of variables, you'll also want to explore different combinations of environments with an eye to testing the strength of your assumptions.
All of this will also probably require the use of a high-performance environment: you'll want to learn about MPI, R's HPC packages, jug, or Spark: each of which would have to be tamed to work with your implementation of the model.
This paper I recently published has a relatively simple agent-based model, along with an analysis and source code, which might help you get started. It may also help you understand the enormity of the undertaking you propose.
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I'd really like to know what knowledge do I have to pursue in order to create scripting languages from the ground up, probably using C++, maybe python, for those are the languages I know.
I've searched through SO similar questions, but nothing comes close of what I'm asking. I intend to understand language processing, not natural language, but scripts that doesn't have the focus on human readability, only on functionality.
My first idea, without any technical background, was to create a scripting language that assimilates a bunch of logical statements and making use of advanced built-in algorithms like logical reasoning, pattern recognition, neural networks an statistical analysis, in order to provide lots of useful(or not) information.
Sorry my bad english, I learned online, as almost everything I cited here :D and that kinda explains my lack of theorical background.
Thanks in advance.
"From the ground up" is a quite relative term, especially if you consider Python as the implementation language. I think what you are looking for is the implementation of a domain specific language (DSL). Good starting points might be this book or this one. DSLs are a wide topic, so if you provide more details, we might be able to give better tips.
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I thought one of the best ways to familiarise myself with C/C++, is to make a helpful library. I was maybe thinking like a geometry library, like to calculate areas, surface area, etc. It would be useful in game programming. Or maybe an algebra library, like for different formulas like the distance formula, quadratic formula, etc. Or maybe like a standard library for very simple functions, like calculating the number of items in an array.
If it is for the sake of an exercise, writing a library to deal with fractions is a good one.
http://en.wikipedia.org/wiki/Fraction_(mathematics)
Implement the basic operations and a way to print them.
Find a problem that you need to solve. Look around to see if a library exists already. If not, then solve it in a way that others can benefit and put the library up on something like github.
But please be prepared to support it if you want to really see it being used - nothing worse than a open source project that isn't well supported.
I'd encourage you to try and come up with an application that would make use of the library. A game, a business app, whatever. Maybe even come up with an application idea first then determine what libraries you would need that aren't readily available.
That way you know you'll be creating something of practical value and not just undertaking a purely intellectual exercise. Try and avoid just plucking a library idea out of the air as you'll inevitably reimplement something that already exists. That's fine for you to learn but it would be awesome if you could create something others could benefit from in the process :)
Also, your application will provide a ready made test for your library.
Much of what you're listing has been done and can be found in Boost and or GSL. If learning is your goal, how about write a Qt application that uses some of these math functions?
Creating 'toy' level libraries doesn't help much on learning C++. I'd suggest you look at the libstdc++ bugs, try to understand and help fixing some ones.