How Can you redesign this code? Same result but different structure

My Code:

clear

format compact

close all

randn('seed',0)

% Definition of mu's and Sigma

% Mean vectors and covariance matrix

m1=[0 2]'; m2=[0 0]'; S1=[4 1.8; 1.8 1]; S2= [4 1.2; 1.2 1];

% Number of data points

n_points_per_class=5000;

% (i) Data point generation

X=[mvnrnd(m1',S1,n_points_per_class); mvnrnd(m2',S2,n_points_per_class)]';

label=[ones(1,n_points_per_class) 2*ones(1,n_points_per_class)];

[l,p]=size(X);

%Plot the data set

figure; plot(X(1,label==1),X(2,label==1),'.b',X(1,label==2),X(2,label==2),'.r'); axis equal

% (ii) Bayes classification of X

% Estimation of a priori probabilities

P1=n_points_per_class/p;

P2=P1;

% Estimation of pdf's for each data point

for i=1:p

p1(i)=(1/(2*pi*sqrt(det(S1))))*exp(-(X(:,i)-m1)'*inv(S1)*(X(:,i)-m1)/2);

p2(i)=(1/(2*pi*sqrt(det(S2))))*exp(-(X(:,i)-m2)'*inv(S2)*(X(:,i)-m2)/2);

end

% Classification of the data points

for i=1:p

if(P1*p1(i)>P2*p2(i))

class(i)=1;

else

class(i)=2;

end

end

% (iii) Error probability estimation

Pe=0; %Probability of error

for i=1:p

if(class(i)~=label(i))

Pe=Pe+1;

end

end

Pe=Pe/p

[Walter Roberson]

Questions like that, without explanation of the reason for rewriting, tend to remind me of students who find someone else's code to do a task and want to rewrite it to hide the fact that they copied the solution instead of creating it themselves.

[Alice Zurock]

I will update, btw this is only practice on my side. I want to see different perspective about algorithms to improve my capability.

Answer 1

[darova]

You can remove some constants from for loop to speed up your code

This part can be shorter and vectorized

% for i=1:p
%     if(P1*p1(i)>P2*p2(i))
%         class(i)=1;
%     else
%         class(i)=2;
%     end
% end
ix = P1*p1 > P2*p2
class = ix + 2*~ix;

[Alice Zurock]

Thanks darova!, Do you have any idea for this part:

% (a) Gemerate Random Data Points

generate=[mvnrnd(mean_1',covariance_1,all_data_points); mvnrnd(mean_2',covariance_2,all_data_points)]';

label=[ones(1,all_data_points) 2*ones(1,all_data_points)];

[l,p]=size(generate);

[darova]

I don't. Looks great

[Alice Zurock]

https://www.mathworks.com/matlabcentral/answers/513886-how-can-you-redesign-this-code-i-want-to-see-different-perspectives

Thanks, could you look and advise me in this link ??

[Alice Zurock]

https://www.mathworks.com/matlabcentral/answers/513886-how-can-you-redesign-this-code-i-want-to-see-different-perspectives

Thanks, could you look and advise me in this link ??