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How to correct the error - ClassificationSVM

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My Matlab code -
clear
load fisheriris
% Only use the third and fourth features
x=meas(:,3:4);
gscatter(x(:,1),x(:,2),species);
% Only use the last two categories
x=meas(51:end,3:4);
group=species(51:end,1);
gscatter(x(:,1),x(:,2),group);
% Linear SVM
svmStruct = fitcsvm(x,group,'showplot',true);
% Kernel SVM
svmStruct = fitcsvm(xdata,group,'showplot',true,'kernel_function','rbf');
% Select different sigma
svmStruct = fitcsvm(xdata,group,'showplot',true,'kernel_function','rbf','rbf_sigma',0.5);
But here I get the error message such as below -
Error in fitcsvm (line 316)
obj = ClassificationSVM.fit(X,Y,RemainingArgs{:});
Error in Untitled (line 11)
svmStruct = fitcsvm(x,group,'showplot',true);

Accepted Answer

Walter Roberson
Walter Roberson on 16 Jun 2018
Edited: Walter Roberson on 16 Jun 2018
svmStruct = fitcsvm(x,group,'HyperparameterOptimizationOptions', struct('showplot',true))
svmStruct = fitcsvm(x,group,'HyperparameterOptimizationOptions', struct('showplot',true), 'KernelFunction','rbf','KernelScale',0.5)
  1 Comment
Walter Roberson
Walter Roberson on 17 Jun 2018
ntry = 10;
kftypes = {'gaussian', 'rbf', 'polynomial'};
nkf = length(kftypes);
svmStructs = cell(ntry,1);
for idx = 1 : ntry
kfidx = randi(nkf);
kftype = kftypes{kfidx};
if ismember(kfidx, [1, 2])
ks = exp(randn());
opts = {'KernelScale', ks};
else
q = randi(20);
opts = {'PolynomialOrder', q}
end
svmStructs{idx} = fitcsvm(x, group, 'HyperparameterOptimizationOptions', struct('showplot',true), 'KernelFunction', kftype, opts{:});
disp(kftype)
celldisp(opts);
pause(2);
end

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More Answers (5)

vokoyo
vokoyo on 17 Jun 2018
Edited: vokoyo on 17 Jun 2018
Many thanks for your correct solution however can you please provide further suggestion such as how to modify the output diagram based on adjusting the parameters?
(Herewith refer to the attached file)
Thank you again

vokoyo
vokoyo on 17 Jun 2018
Edited: vokoyo on 17 Jun 2018
Kindly please help and provide your sample codes as a reference (because this is very important for studies)
After all I am not sure how to perform Matlab programming for Supervised Classification and compare all the results
Here can contact with more detail information - tcynotebook@yahoo.com (my mail)

vokoyo
vokoyo on 18 Jun 2018
Edited: vokoyo on 18 Jun 2018
This is the Matlab code -
clear
load fisheriris
% Only use the third and fourth features
x=meas(:,3:4);
gscatter(x(:,1),x(:,2),species);
% Only use the last two categories
x=meas(51:end,3:4);
group=species(51:end,1);
gscatter(x(:,1),x(:,2),group);
% Linear SVM
svmStruct = fitcsvm(x,group,'HyperparameterOptimizationOptions', struct('showplot',true))
% Kernel SVM
svmStruct = fitcsvm(x,group,'HyperparameterOptimizationOptions', struct('showplot',true), 'KernelFunction','rbf')
% Select different sigma
svmStruct = fitcsvm(x,group,'HyperparameterOptimizationOptions', struct('showplot',true), 'KernelFunction','rbf','KernelScale',0.1)
ntry = 10;
kftypes = {'gaussian', 'rbf', 'polynomial'};
nkf = length(kftypes);
svmStructs = cell(ntry,1);
for idx = 1 : ntry
kfidx = randi(nkf);
kftype = kftypes{kfidx};
if ismember(kfidx, [1, 2])
ks = exp(randn());
opts = {'KernelScale', ks};
else
q = randi(20);
opts = {'PolynomialOrder', q}
end
svmStructs{idx} = fitcsvm(x, group, 'HyperparameterOptimizationOptions', struct('showplot',true), 'KernelFunction', kftype, opts{:});
disp(kftype)
celldisp(opts);
pause(2);
end
Why the output diagram is the same and not any special result?
(Herewith kindly refer to the attached picture)
  6 Comments
vokoyo
vokoyo on 18 Jun 2018
Edited: vokoyo on 18 Jun 2018
The more you write the more problems I get
svm_3d_matlab_vis
Not enough input arguments.
Error in svm_3d_matlab_vis (line 2)
sv = svmStruct.SupportVectors;
I think I need to stop here
Anyhow thank for the first answer
Walter Roberson
Walter Roberson on 18 Jun 2018
It sounds as if you are calling svm_3d_matlab_vis without passing in any parameters.

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Don Mathis
Don Mathis on 18 Jun 2018
FITCSVM does not have an argument named 'showplot'. When I run your original code in R2018a I get this:
Error using classreg.learning.FitTemplate/fillIfNeeded (line 612)
showplot is not a valid parameter name.
Error in classreg.learning.FitTemplate.make (line 124)
temp = fillIfNeeded(temp,type);
Error in ClassificationSVM.template (line 235)
temp = classreg.learning.FitTemplate.make('SVM','type','classification',varargin{:});
Error in ClassificationSVM.fit (line 239)
temp = ClassificationSVM.template(varargin{:});
Error in fitcsvm (line 316)
obj = ClassificationSVM.fit(X,Y,RemainingArgs{:});
Error in Untitled3 (line 11)
svmStruct = fitcsvm(x,group,'showplot',true);
  6 Comments

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Don Mathis
Don Mathis on 25 Apr 2023
Edited: Don Mathis on 25 Apr 2023
svmtrain() was replaced by fitcsvm(), and fitcsvm does not have a 'showplot' argument. Making a 2D plot of data points and support vectors in not built-in to fitcsvm, nor the object that it returns, ClassificationSVM.
If you have a 2D input space and you want to plot points and support vectors, you can see an example of how to do that here: https://www.mathworks.com/help/stats/classificationsvm.html#bt7go4d

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