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I have a random number sequence (say 6 bytes)
I now want to generate a shorter sequence from the original sequence (say 3 bytes)
What is the best way of acheiving this so that the randomness of the original sequence is preserved.
Lets say I run a SHA-1 hash code on the original sequence and then grab some bytes from the hashed output. Does the randomness decrease, increase, or stay the same.
The basic question is - Does a Hash Code of a random number produce less random, more random or same randomness.
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I want to understand the physical significance of n raise to some decimal power.
Like when i say 2^5. I understand that it means 2 multiplied 5 times. But how do i analyse 2^0.1.
Please suggest.
2^0.1 is the tenth root of 2. For rational powers, x^(p/q)=(x^p)^(1/q) is a combination of powers and roots.
For general real numbers,
x^y = exp(log(x)*y).
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Number of digits that are present in the maximum number that is formed using three digits?
Maximum factorial that is formed by three digits?
This was a question asked on a site.
I am not able to understand is there any thing tricky i am not getting?
i have tried 3 and 720 but it is incorrect
The maximum factorial which can be formed using 3 digits is 999!.
The answer can be easily obtained from wolfram alpha.
Number of digits in 999!.
999!=Answer
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More a general question, but since I am using R -> tags
My training data set is 15,000 entries big from which around 20 i would like to use for positive data set -> building up the svm. I wanted to use the remaining resampled dataset as my negative dataset, but i was wondering, it might be better to take the same size (around 20) as the negative data set, otherwise it's highly imbalanced? Is there an easy approach to pool then the classifiers (ensemble based) in R after 1000 rounds of resampling? (or even with the e1071 package)
Followup question: I would like to calculate a score for each prediction afterwards, is it fine just to take the probabilities times 100??
Thx
You can try "class weight" approach in which the smaller class gets more weight, thus taking more cost to mis-classify the positive labelled class.
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I have found this formula for computing Pi value:
But I need to compute only(for example - 1000th) number of Pi value. How I can do it with provided formula?
Thanks.
What you want is called a "spigot algorithm". Take a look at [1] in the section "BBP digit-extraction algorithm for pi". Good luck and have fun.
[1] http://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93Plouffe_formula
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I'm a student just learning how to use R and thus far I've made a bit of progress. I'm snagging at a question which asks: For what values of i does Y equal 3?
the data set: c(3,5,2,3,5,4,4,2,3,5)
If I understand your question correctly, you want the index, i inside the data set (in this case, a vector) Y such that Y[i]=3?
Then you just need to use the which function. For more information, make sure you try reading the help files, which you can invoke using the command ?which or help(which)
Now, some code:
# Your data
Y <- c(3,5,2,3,5,4,4,2,3,5)
# Find the index where Y is equal to 3
which(Y==3, arr.ind=TRUE)
And welcome to SO. This is a pretty common question for beginners, so next time, make sure you Google or search around for a solution to elementary problems such as these. Have a good day.