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Fun

Image Analyst
Last activity 2023-10-31

BATLAB

Just in time for Halloween.

meme

Fun

Chen Lin
Last activity 2024-3-12

What costume are you going to wear for Halloween?

Share your fun photos in the comments!

halloween

Ideas

Julian
Last activity 2024-2-5

Naming x-values in bar(x,y)

I know the latest version of MATLAB R2023b has this feature already, put it should be added to R2023a as well because of its simplicity and convenience.

Basically, I want to make a bar graph that lets me name each column in a basic bar graph:

y=[100 99 100 200 200 300 500 800 1000];

x=["0-4" "5-17" "18-29" "30-39" "40-49" "50-64" "65-74" "75-84" "85+"];

bar(x,y)

However, in R2023a, this isn't a feature. I think it should be added because it helps to present data and ideas more clearly and professionally, which is the purpose of a graph to begin with.

General

Kilsu Kim
Last activity 2023-10-19

Just for Fun and Curiosity: Guess the MATLAB Compile Threshold on Windows

Recently, I came across a post about the JIT compiler on this Korean blog. In the post. The writer discussed the concept of the "Compile Threshold" and how it is calculated.

"The JVM accumulates the number of calls for each method called and compiles when the number exceeds a certain number. In other words, there is a standard for checking how often it is called and then deciding, 'It is time to compile.' This standard is called the compilation threshold. But what is this and why should it be used as a standard?"

The concept of the "Compile Threshold," as used above, seems to be more commonly associated with Tracing just-in-time compilation.

The writer used the simple Java code below to calculate the threshold.

for (int i = 0; i < 500; ++i) {
  long startTime = System.nanoTime();
  for (int j = 0; j < 1000; ++j) {
 	new Object();
  }
  long endTime = System.nanoTime();
  System.out.printf("%d\t%d\n", i, endTime - startTime);
}

Since the MATLAB execution engine uses JIT compilation, I just wanted to perform the same experiment that the writer did.

I experimented using simple codes based on the code in the blog. I iterated a function 500 time using for-loop and calculated the execution time for each iteration using tic and toc. Then I plotted the execution time for each loop as blow. First five execution times are much higher than followings (10 times!) The test is very rough so I am not sure that I can conclude "MATLAB has Compile Threshold and it is 5!" but this value is actually correct ;-)

t0 = 0;
tfinal = 10;
y0 = [20;20];
timeToRun = zeros(500,1);
for i = 1:500
    tStart = tic;
    [preypeaks,predatorpeaks] = solvelotka(t0, tfinal, y0);
    tEnd = toc(tStart);
    timeToRun(i) = tEnd;
end

General

Toshiaki Takeuchi
Last activity 2023-10-23

Do you use VS Code for writing MATLAB Code?

VS Code Extension for MATLAB was introduced back in April and has been downloaded 75K times since. Do people here use VS Code for writing MATLAB code?

vs code

Ideas

Matt J
Last activity 2024-3-1

Implicit expansion for CAT()

Would it be a good thing to have implicit expansion enabled for cat(), horzcat(), vertcat()? There are often situations where I would like to be able to do things like this:

 x=[10;20;30;40];
 y=[11;12;13;14];
 z=cat(3, 0,1,2);
 
 C=[x,y,z]
 

with the result,