Now that you see bsxfun in action, can you think of uses for this function in your work? Let me know here. In this example, bsxfun performs fastest. Next see the timing calculation done using bsxfun. install.packages('matlab', repo' depT) library(matlab) repmat(1, 3) same as ones(3) repmat(1, c(3, 3. Since I can't index into the results of a function without assigning the output to a variable, I create an intermediate I need to do the same thing without repmat and I want to be able to set up one function call for performing the calculation so I can use timeit. One thing I notice with the repmat solution is that I need to create the vector mean(A) for the function. If B repmat(A, 3, 2), then B is the following matrix AA AA AA So. What do I mean Lets say you have a matrix A. Here's an illustative example with a vector. Answer (1 of 2): It is used to replicate a matrix. Is to index into the array with ones in the dimension to replicate. Repmat uses a variety of techniques for replicating an array, depending on the details of what's being replicated.
includeUse MATLABs repmat function to plot a discrete sequence with 6 repetitions of (o, 1, 2, 3, 4), starting at n 0. If thats the case, something like this might do the trick for you C. Transcribed image text: Exercise Set 8, continued 5. Many times to run it to get meaningful results, and more.įrepmat = A - repmat(mean(A),size(A,1),1) I am not sure I get what youre after here but it sounds like you just need a C function to repeat elements in an array. timeit carefully warms up the function by running it enough so the times are not subject to first-time effects, figuring out how Then I pass that function handle to timeit. It is a powerful and commonly used function as it can be used to 'vectorize' code. First I create an anonymous function that does my calculation.
![matlab repmat matlab repmat](https://media.cheggcdn.com/media/675/6752ec6d-af25-4668-b64a-854a2c722367/phphM0OZj.png)
Using the most excellent timeit utility that Steve Eddins posted to the file exchange, I now time the repmat calculations.
#Matlab repmat code
A possible downside, especially since bsxfun is relatively new, is that the code doesn't, at first reading, appear as obvious. This is there is no need for a large intermediate array the same size as A.
![matlab repmat matlab repmat](https://www.mathworks.com/matlabcentral/mlc-downloads/downloads/submissions/41610/versions/1/previews/html/examples_01.png)
![matlab repmat matlab repmat](https://img-blog.csdnimg.cn/20181226165545654.png)
From A First Course in Machine Learning, Chapter 5.And now here's the code I'm tempted to write, safely tucked inside the confines of a try statement.Īs you can see, MATLAB does not allow binary operators to work on arrays with different sizes (except when one of the inputs