Unable to run the code given in the link: https://in​.mathworks​.com/help/​stats/code​-generatio​n-for-pred​iction-of-​machine-le​arning-mod​el-using-m​atlab-code​r-app.html

Hi,

I have been trying to run the code given the following link: https://in.mathworks.com/help/stats/code-generation-for-prediction-of-machine-learning-model-using-matlab-coder-app.html. Currently I am using Matlab2021a version. Do I need to install 2021b to run this code or am I missing something else?

[Walter Roberson]

What problem are you observing?

[Doli Hazarika]

While running the following line of code:

Mdl = fitcensemble(X,Y,'Method','Subspace','NPredToSample',5, ...
    'Learners',learner,'NumLearningCycles',13); 

it is showing an error stating:

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other
syntax error. To construct matrices, use brackets instead of parentheses.

[Walter Roberson]

There is a possibility that it is complaining about a previous line not being complete.

[Doli Hazarika]

load ionosphere
rng('default')  % For reproducibility
learner = templateKNN('NumNeighbors',2);
Mdl = fitcensemble(X,Y,'Method','Subspace','NPredToSample',5, ...
    'Learners',learner,'NumLearningCycles',13);

this are the lines of code that I am running. It shows the following error:

File: fitcensemble.m Line: 1 Column: 33
Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other
syntax error. To construct matrices, use brackets instead of parentheses.

Error in Classification (line 4)
Mdl = fitcensemble(X,Y,'Method','Subspace','NPredToSample',5, ...

[Walter Roberson]

Please show

which -all fitcensemble
dbtype fitcensemble 1:5

[Doli Hazarika]

>> which -all fitcensemble
E:\Doli\MATLAB codes\fitcensemble.m
C:\Program Files\MATLAB\R2021a\toolbox\stats\classreg\fitcensemble.m  % Shadowed
>> dbtype fitcensemble 1:5

1     function Mdl = fitcensemble(X,Y,'Bag')
2     %UNTITLED Summary of this function goes here
3     %   Detailed explanation goes here
4     rng('default')
5     t = templateTree('Reproducible', true);

[Walter Roberson]

Your E:\Doli\MATLAB codes\fitcensemble.m is interfering with calling the Mathworks fitcensemble function.

function Mdl = fitcensemble(X,Y,'Bag')

That is not valid syntax in defining a function. If you want to force Bag as the third parameter then you would want to do something like

function Mdl = my_fitcensemble(X,Y,varargin)
   Mdl = fitcensemble(X, Y, 'Bag', varargin{:});

[Doli Hazarika]

I tried but it is still showing the following error. I am unable to understand from the error

Maximum recursion limit of 500 reached.

Error in fitcensemble (line 7)
Mdl = fitcensemble(X,Y,'Bag',varargin{:});

Caused by:
    Maximum recursion limit of 500 reached.

[Walter Roberson]

Notice that you need to rename your function and the file it is in.

[Doli Hazarika]

Did that too....still didn't work!

[Doli Hazarika]

And also the code is not running online.

[Walter Roberson]

It does work.

%illustration that the code DOES work when saved to a file name that does
%not conflict

%first write the code into a .m file
PROGRAM = "load ionosphere\nrng('default')  %% For reproducibility\nlearner = templateKNN('NumNeighbors',2);\nMdl = fitcensemble(X,Y,'Method','Subspace','NPredToSample',5, ...\n    'Learners',learner,'NumLearningCycles',13);";
fid = fopen('my_fitcensemble.m', 'w');
fprintf(fid, PROGRAM);
fclose(fid);

%now verify that the code looks like we expect
dbtype my_fitcensemble

1     load ionosphere
2     rng('default')  % For reproducibility
3     learner = templateKNN('NumNeighbors',2);
4     Mdl = fitcensemble(X,Y,'Method','Subspace','NPredToSample',5, ...
5         'Learners',learner,'NumLearningCycles',13);

%now run the code

my_fitcensemble

%check the results
whos

  Name               Size             Bytes  Class                                               Attributes

  Description        5x79               790  char                                                          
  Mdl                1x1             613095  classreg.learning.classif.ClassificationEnsemble              
  PROGRAM            1x1                562  string                                                        
  X                351x34             95472  double                                                        
  Y                351x1              37206  cell                                                          
  ans                1x1                  8  double                                                        
  fid                1x1                  8  double                                                        
  learner            1x1               2078  classreg.learning.FitTemplate                                 

[Doli Hazarika]

Yes it worked this way. But instead of creating a function and calling it directly why are we doing it this way?

[Walter Roberson]

I did it that way to prove that if you had a file with that content that it would work. All you need is the my_fitensemble file, not the code that creates it.

[Doli Hazarika]

Thanks for your time and help.