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# the cyclist

3,889 total contributions since 2011

Data scientist at Cohen Veterans Bioscience; Obsessive runner. Professional Interests: Predictive modeling, statistics.

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Data (.txt) into matrix
This works on the small file I attached here. If the format is not exactly what you have, maybe you can still figure out how to ...

17 hours ago | 0

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how can I effectively compute expected value by histogram approximation of probability desnsity function
There might be some nuances in the numerical integration, but here is the basic idea. You need to approximate the integral of x ...

21 hours ago | 0

Switch not recognizing that 0 is greater than -1
Quoting the Tips section of the documentation for switch: "A case_expression cannot include relational operators such as < or >...

1 day ago | 0

Simplify code with nested if
% A little pretend data, where I only fill in the 4th column with a few months C = cell(5,6); C(:,4) = {'Jan';'Jan';'Dec';'Mar...

1 day ago | 0

I have problem writing a matlab function
The coefficient (5.1/(4*pi^2)) is multiplying the term you have called x, which is not correct. It might have been easier t...

4 days ago | 1

combination and their sum
A = [4 2; 5 7; 3 1]; m = size(A,1); output = []; for j = 1:2 output = [output; A(:,j)']; for i = 1:m ...

5 days ago | 1

Why is the or statement making something true?
You need Overall_max_score==scores(1,3) | Overall_max_score==scores(2,3) <etc> You could do this more concisely as ismember(O...

7 days ago | 0

Principal Component Analysis - return data (stock market data)
You might want to check out my tutorial-style PCA answer here. I think one helpful way to think about your 262x5 output is that...

7 days ago | 0

poisson random distributoin with zeros
If you have the Statistics and Machine Learning Toolbox, then BIG = 80000; SMALL = 1000; MEAN = 2400; idx = randsample...

8 days ago | 0

output = zeros(n,1); for i=1:n output(i) = length(find(yy(1:numel(yy),1)==i)); end output That will still write the ful...

9 days ago | 0

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How to make diagonal matrices from a single column
B = zeros(8,2); B(1:2:end,1) = A(1:2:end); B(2:2:end,2) = A(2:2:end);

9 days ago | 0

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How to specify a number to the specified position in the array？
There's probably not an built-in function that does just that, but it's easy to do it with basic array manipulations. Here is on...

10 days ago | 0

How to plot outliers from mean
There are three steps: Create an algorithm to define the outliers Identify the points that meet that definition Plot those po...

11 days ago | 0

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Function with euler not working properly
The images you posted don't show up for me, either. Your code ran for me, and yielded this figure: I think you might have wa...

11 days ago | 0

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Comparing elements of a vector.
[g(:,2), idx] = unique(R); g(:,1) = T(idx);

13 days ago | 1

Create lookup table for cell array
Is this what you want? [num2cell(1:9)' Codeword(:)]

13 days ago | 0

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Check all values in a table if any is "NAN"
This may work for your case tbl = fillmissing(tbl,'constant',1); assuming the NaNs are the only values that count as missing f...

15 days ago | 1

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Need help creating an matrix that includes probability
There are many ways to generate pseudorandom numbers in MATLAB. Since this sounds like homework, I'll just point you to this doc...

15 days ago | 0

Plot two arrays as x and y and select the maximum point
The first thing is trivial ... plot(V,M,'.') I don't understand what you mean by "maximize both" or "do it graphically".

15 days ago | 0

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Computing determinant of matrix A using LU factorization
If I use the lu function from MATLAB (instead of your lufact function), I get the expected result. So, I'd double-check your LU ...

15 days ago | 0

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses
I've spotted two errors so far. (1) Where you have 0.5th where you presumably want 0.5*th (2) In that same line, you typo'e...

15 days ago | 0

convert string to number or array
I'm guessing it's the space that is causing the problem. Run your array through x = regexprep(x,' ',''); first to remove the s...

15 days ago | 1

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Scatter3: How can I change the size of a particular marker?
This puzzled me for a bit -- until I read the documentation a bit more carefully. For scatter3, the marker size specified is th...

16 days ago | 0

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Using two vectors to get the third one
This is virtually equivalent to Fangjun's solution. But it uses some intuitive variable names (and comments) to help you underst...

16 days ago | 1

Index exceeds the number of array elements (5)
You have initialized x and y to be vectors of length 5. But in your for loop, i reaches the value value 5, and then you try to a...

16 days ago | 0

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Plot function is not working
Your plotting code is trying to select just one element from the t and y vectors. I think you want this instead: plot(t,y) (I...

16 days ago | 0

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Passing array as an input argument
Is that how you are calling the function, or is it the function header (inside the function file itself)? If that is how you ar...

16 days ago | 0

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