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Topic: Not-totally random set generation (Read 1760 times) |
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howard roark
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Not-totally random set generation
« on: Dec 10th, 2008, 12:05am » |
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I would like generate a data set that is not totally random. I have an idea . Please comment about its flaws. If you have any other function suggest that too.
Suppose A is an array, of size n, that needs to be filled with numbers. As I told you it shouldn't be totally random.
The function I thought of is follows:
A[i]= rand(0,1) + slope*(i) ; 0<=i<=n and slope<1/n
Explanation of the function: When slope tends to zero the above function becomes just like random number generator(between 0 &1)
rand(0,1) generates a random number between 0 and 1
This is one of the data sets I am planning to consider in my project.
Can you please tell me the advantages and disadvantages of this function.
Can anyone tell me if they have a better not-totally random set generation function.
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towr
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Re: Not-totally random set generation
« Reply #1 on: Dec 10th, 2008, 1:10am » |
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What do you want to do with your dataset?
Personally I'd stick a parameter in front of the "rand(0,1)" as well. It makes sense to take Data+Noise, where you can manipulate the amounts of both. Or perhaps use an overall amplitude, plus a factor for the noise: A(D+f*N)
On the other hand, it may make sense to put noise on the magnitude of the data, A*D*(1+f*N)
Or to combine the two A*(D*(1+f1*N1)+f2*N2)
But without knowing what you are using the dataset for, it's like trying to recommend tourist attractions without knowing what country you're in.
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howard roark
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Re: Not-totally random set generation
« Reply #2 on: Dec 10th, 2008, 7:31am » |
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Quote:What do you want to do with your dataset?
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I am working on analysis of parallel sorting algorithms. (Hyperquicksort and parallel merge sort)
I worked on these two input formats (data set):
1) Random data set
2) Fully sorted data set
I also wanted to work on a data set which is not totally random.
@towr
Thanks for your help
Any more comments now
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Grimbal
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Re: Not-totally random set generation
« Reply #3 on: Dec 10th, 2008, 7:56am » |
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Another case of partially-random data that can happen in the real world is a set of perfectly sorted elements with a number of random elements appended at the end.
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towr
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Re: Not-totally random set generation
« Reply #4 on: Dec 10th, 2008, 11:02am » |
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You could start with a sorted array (or the reverse), then make K random swap, for some value of K (for example, you could swap ~25% of all elements, or just 10 in total)
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