In the following code, I fit a gaussian mixture model (GMM) to some randomly sampled data. I do this twice. Each time, the data represent two well separated gaussians, the only difference being the seed I use for the random number generator.
N = 100000;
EFFECT_SIZE = 5;
seedList = [1 6];
for s = seedList
rng(s)
X = [randn(N,1); randn(N,1)+EFFECT_SIZE];
figure
hist(X,101)
GMModel = fitgmdist(X,2)
end
Kshitij Singh answered . 2024-04-13 16:11:58
Hi cyclist,
the default starting values are selected from the data at random, and you have discovered that this sometimes does not work well. There's an argument 'replicates' that you can use to have it try this multiple times and deliver the bone fit. However, in more recent releases including R2014b there is a new argument 'Start','plus' that uses a better starting method, one based on the kmeans++ algorithm for clustering. Here's a variant of your function that shows the relative performance of the default random start and the 'plus' start:
N = 100000;
EFFECT_SIZE = 5;
seedList = 1:20;
means1 = zeros(length(seedList),2);
means2 = zeros(length(seedList),2);
for s = seedList
s
rng(s)
X = [randn(N,1); randn(N,1)+EFFECT_SIZE];
rng(s) % randomness is used in the fit also
GMModel = fitgmdist(X,2);
means1(s,:) = GMModel.mu';
rng(s)
GMModel = fitgmdist(X,2,'start','plus');
means2(s,:) = GMModel.mu';
end
plot(means1(:,1),means1(:,2),'bx',means2(:,1),means2(:,2),'ro')
Matlabsolutions.com provides guaranteed satisfaction with a commitment to complete the work within time. Combined with our meticulous work ethics and extensive domain experience, We are the ideal partner for all your homework/assignment needs. We pledge to provide 24*7 support to dissolve all your academic doubts. We are composed of 300+ esteemed Matlab and other experts who have been empanelled after extensive research and quality check.
Matlabsolutions.com provides undivided attention to each Matlab assignment order with a methodical approach to solution. Our network span is not restricted to US, UK and Australia rather extends to countries like Singapore, Canada and UAE. Our Matlab assignment help services include Image Processing Assignments, Electrical Engineering Assignments, Matlab homework help, Matlab Research Paper help, Matlab Simulink help. Get your work done at the best price in industry.
Australia
UK
UAE
Singapore
Canada
New
Zealand
Malaysia
USA
India
South Africa
Ireland
Saudi
Arab
Qatar
Kuwait
Hongkong
Copyright 2016-2023 www.matlabsolutions.com - All Rights Reserved.
Disclaimer : Any type of help and guidance service given by us is just for reference purpose. We never ask any of our clients to submit our solution guide as it is, anywhere.
