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the cyclist


3,621 total contributions since 2011

Principal Scientist at PatientsLikeMe; Obsessive runner. Professional Interests: Predictive modeling, statistics.

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Answered
Missing factor using rule of three?
Try (0.004*4*pi)/(2*pi) The reason your syntax does not work is that it will divide by 2, and then multiply by pi. See order ...

5 days ago | 1

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Answered
How can I average the first 14 columns, the second 14 columns, and so on and so forth?
Assuming you actually want to average over columns (see my question above), I believe out = movmean(M,[0 13],2); out = out(:,1...

18 days ago | 1

Answered
delete rows from matrix if some of its elements equal all elements in another rows another different dimension matrix?
Here is one way: Sw = [2 3 6 25 11 3 6 7 8 9 3 6 25 8 9 3 6 25 11 11 3 4 5 6 25 4 ...

19 days ago | 0

Answered
Can copula PDF value exceed 1?
Yes, a probability distribution function can have values greater than 1. Remember that the PDF is not the probability at that l...

20 days ago | 0

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Answered
What happen with confusion matrix ?
It looks like you have 55 observations. 51 of them were classified correctly (along the diagonal, indicated in green). But 4 of ...

25 days ago | 0

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Answered
Vectorized Search of substrings in Cell Array
Discovered a much cleaner way: contains(t,'bc');

27 days ago | 0

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Vectorized Search of substrings in Cell Array
Here is one way: cellfun(@(x)not(isempty(x)),strfind(t,'bc'))

29 days ago | 1

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Conversion of any base (n) to a base 10 number?
There is a thorough answer to this question here.

1 month ago | 0

Answered
How to create this matrix without hardcoding the values
Here is one way. r = [ 1.5355 + 0.0000i -1.0914 + 1.0781i -1.0914 - 1.0781i 0.3621 + 1.3117i 0.3621 -...

1 month ago | 0

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Answered
how to make a curve of Poisson, Rayleih, t , ....etc distribution of my random data (in histogram)
If you have the Statistics and Machine Learning Toolboox, then you could use the fitdist function. It will fit a large variety o...

2 months ago | 0

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Answered
gevfit error: Operands to the || and && operators must be convertible to logical scalar values
That code works for me, in both 2018b and 2019a. Does this happen with a freshly started instance of MATLAB? If so, you might ...

2 months ago | 0

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Answered
how to find out wether the array is Hill or not?
I think this is right, but I have to admit I have not thoroughly checked it: % Original data a=[1,2,2,3,3,4,4,2,-1,-1]; % F...

3 months ago | 0

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Answered
are there workbook front ends for matlab?
Live scripts and functions are a notebook-like functionality within MATLAB.

3 months ago | 0

Answered
how can I generate data mixture of 2 Normal distributions and has the form f(x) = 0.4X1 + 0.6X2 where X1 ~ N(0.4 ,0.15^2) and X2 ~ N(0.7 , 0.09^2)?
Here is one way: % The number of random samples to generate N = 10000; % First, generate a binomial variable, which 40% of ...

3 months ago | 1

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Answered
Accumulate previous values in time serie
You should be able to use the movsum command.

3 months ago | 0

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Answered
Scanning a column in matrix with repeated values
This code does the initialization. I'm still trying to figure out what you mean about filling it in. [Edited afterward to fill ...

3 months ago | 0

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Answered
Finding boundaries of kmeans clustering
Use the centroid coordinates as input to the voronoi command. xy1 = [randn(50,1) randn(50,1)]; xy2 = [randn(50,1)+5 randn(50...

3 months ago | 0

Answered
How do I only keep specific values in an array of numbers?
You could do intersect(yourArray,65:90) You also should not use sort as a variable name, because it is a MATLAB keyword. You w...

3 months ago | 0

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Answered
plotting projectile with drag
If I increase cd to a very large value, for example cd=10000; then I see the impact of drag -- the trajectory is no longer a p...

3 months ago | 0

Answered
Assign different colors to multiple plots without loop
Here is one way: ColorSpec = [0 0 0; 1 0 0; 0 1 0; 0 0 1]; % Pretend data x = sor...

3 months ago | 0

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Answered
calculate total percentage on either side of histogram
Taking a very different tack ... maybe you'd find the cdfplot command useful?

3 months ago | 0

Answered
Why does 7*(0.1) - 0.7 = 1.1102e-16 whereas 9*(0.1)-0.9 =0 in MATLAB?
See the section "Accuracy of Floating-Point Data" in this documentation page. Some of those combinations are represented by the...

3 months ago | 0

Answered
Rearranging a Vector Back Again
% Original x x = [0 0 1 1 0 1 0 0 1 1]; % Sorted x [x_sorted,indices]=sort(x,2); % Original x recovered from the sorted...

4 months ago | 0

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Answered
How do you transpose a part of a column into more rows in Matlab?
If X is your original matrix ... Y1 = reshape(X,3,3,[]); Y2 = permute(Y1,[2,1,3]); Y3 = reshape(Y2,3,9); Y3 is the matrix yo...

4 months ago | 2

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Answered
Which mldivide ('\') function is better
I highly doubt that a bug was found in mldivide later than 2008, so I doubt the later function is "more correct" or "more accura...

4 months ago | 0

Answered
Selecting a range of X values from an array
ind = find(data(:,1)>630 & data(:,1)<700);

4 months ago | 1

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Answered
Create a loop to find Beta for each period, OLS
The first thing I notice is that absolutely nothing inside of your for loop depends on i. So, the output of your loop will be id...

4 months ago | 0

Answered
Couldn't find the position of a value in vector
The value is not exactly equal to 0.05, due to floating point representation. Try tol = 1.e-6; k=find(abs(q-0.0500)<tol); Rea...

4 months ago | 0

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Answered
I have a problem with plotting two vectors, I want to vary 'z' by a certain amount and 'x' by another amount and plot versus each other, how can i make the matrix dimensions match?
Well, it's really up to you to decide. You have a 24-element vector, and a 28-element vector. Which of those elements align wit...

4 months ago | 0

Answered
How to create an array/card bank to add elements into later and be empty at the start
Yes, there is a way to do this. (I am tempted to stop there, because that was your question.) It's not very clear what sort of ...

4 months ago | 0

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