# the cyclist

### Alden Scientific

Head of Modeling and Statistics at Alden Scientific. Obsessive runner. Professional Interests: Predictive modeling, statistics. (I don't respond to email via author page, but will usually look at a question if you send me a link to it.)

**Programming Languages:**

Python, R, MATLAB, SQL

**Spoken Languages:**

English

**Statistics**

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**Content Feed**

GMM - gaussian mixture as summation of pdf

It will be easier to help when we see the data, but the general idea would be to sum the pdfs of your best_model, weighted by th...

en dag ago | 0

How to efficiently sum values in matrix using indices from a logical statement of a different matrix

%Set up matrix of values A = [0 1 2 3; 1 2 3 4; 2 3 4 5]; %Set up matrix of probabilities B = [0.05 0.02 0.03 0.1...

en dag ago | 0

| accepted

Center of gaussian mixed distribution area

I downloaded and looked over the paper. I am also not certain what they mean by the "center" of the mixed gaussian model. But, ...

en dag ago | 1

Finding data in matrice

If M is your data, bigChange = abs(diff(M,1,3)) >= 24;

2 dagar ago | 1

| accepted

How to find mean of cell array

Here is one way: cellfun(@(x)mean(x,3),h,'UniformOutput',false)

2 dagar ago | 1

How to draw the delta signal in matlab

Do you mean the Dirac delta function? If so, then dirac might help you. Also, if you do mean the Dirac delta, I hope you realiz...

2 dagar ago | 0

How can i do a Multiple Linear Regression

My advice would be to try to read and understand the example from the documentation page for regress. Better yet, I would use t...

2 dagar ago | 0

How do I pick selected values in a matrix

You want the fraction of zeros in the array? A = ... [0 0 0 0 0 2 2 2 0 0 2 ...

2 dagar ago | 0

| accepted

Good practice in conditional test with categorical variable

The reason you are getting this mlint warning isn't really about the categorical variables at all. It is because you are trying ...

3 dagar ago | 0

| accepted

sqrtm vs chol to produce draws the multivariate normal distribution

A common reason for not having a positive semidefinite correlation matrix is when the pairwise correlations are estimated (or ob...

4 dagar ago | 1

Truncated answers when querying chatgpt with Matlab

My impression from searching the same topic is that there is an unpublished token limit (which will roughly translate to a chara...

5 dagar ago | 0

How to extract diagonal elements of multidimensional array ?

rng('default') N = 4; A = rand(N,N,N); A(1:N^2+N+1:end)

6 dagar ago | 3

| accepted

Using histcounts to determine loose data mode

I think that you have a case of the XY problem here. Namely, you are asking about your solution to a particular problem, but I s...

6 dagar ago | 0

plotting functions over domain

f = @(x,y) (x.^2 + 3*y.^2).*exp(1 - x.^2 - y.^2); % I'm not certain about your notation here x = -1 : 0.05 : 1; y = -1 : 0.0...

6 dagar ago | 1

I have 2 columns, i want to find the maximum in the second column and then know what value it is next to on the first column

% Pretend data aw = rand(1221,2) + 250; % Max 2nd col in range, with index [maxW,idx] = max(aw(651:1221,2)); % Absorbanc...

7 dagar ago | 0

Combinations and Matrices?

There just happens to be a very obfuscated way to do this: M = dec2bin(0:2^20-1) - '0'; size(M)

8 dagar ago | 0

| accepted

How does the classification learner app implement k-fold cross validation?

I am most definitely not an expert in this app, but I built a simple model using the default settings, and then exported the fun...

8 dagar ago | 0

| accepted

fit tool with errors in x and y

I am late to seeing this question, but FYI there is a submission to the File Exchange that does linear, univariate Deming regres...

9 dagar ago | 0

Issues plotting simple bar graph.

The error message is quite clear. Your X values are not unique. Let's look at a simpler example: x = [1 2 2]; y = [3 5 7]; ...

9 dagar ago | 0

Strategy on how to save data from multiple runs of an experiment where variables changes

There's probably no single best answer here. But if the overall scale of the data is not too large, storing everything in one ta...

11 dagar ago | 0

| accepted

Pie chart with arrows without text coincidence on each other

This is a case where you need to ask yourself, "What is the information I really need to convey to my audience, and what is the ...

11 dagar ago | 1

| accepted

How to transpose every cell in a table?

% If data are in a cell array c = {rand(1,7),rand(1,27)} ctrans = cellfun(@transpose,c,'UniformOutput',false) % If data...

11 dagar ago | 1

| accepted

what is the meaning of this error? how to stop this error?

One reason for getting that error is having text in a line before the function definition. So if your function file looks like t...

11 dagar ago | 0

How to give variable name to a Mat file?

Your code is looking for a variable named X1. The file X1.mat that you load does not contain a variable named X1, it is just nam...

11 dagar ago | 0

| accepted

Append multiple values in one variable

Assuming the image are all the same size, 512x512, then I would "stack" them in the 3rd dimension, then convert everything to a ...

11 dagar ago | 0

Use cvpartition to generate a set of random 3 numbers 100 or 1000 times

I don't think cvpartition does what you intend, and I am quite sure that you don't understand its output. Rather than explain cv...

12 dagar ago | 0

Most efficient way of looking up values in an array.

One simple step that could speed up your code a lot would be to preallocate memory for your output array. Put myIntegers = zero...

12 dagar ago | 0

matlab some polyfit problem

It is admittedly confusing, and I have fallen into this trap myself. The reason for the difference is described in the documenta...

12 dagar ago | 0

How to calculate the correlation matrix of two jpg images of the same size?

The result is what I would expect. Imagine this smaller example, with two images of 9 random pixels: rng default N = 3; img...

13 dagar ago | 0