Calculating statistical PDF and percentiles over matrices
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I was wondering if there is a ways to calculate and represent the statistical properties of a matrix and then present it in a countour/image/pcolor way.
Assuming we have a matrix, and the percentile values are to be found for every point of the matrix, the prctile allows to calculate either or columns or rows only. Same goes for the PDF fitting.
x=magic(100); % matrix of 100x100
prctile(x,,1); % calculates the percentiles for column x
so i get a 1x100 in this case
prctile(x,,2); % calculates the percentiles for rows x
the result is 100x1 vector
What I want to though is to have the matrix constant or/and fit PDF or percentile for every point
Is there a way to achieve this?
p.s The process involves a set of matrices with exact same dimensions, but I try to keep the question simple so as other people may find it useful.
Alessandro Masullo on 27 Jan 2015
You can replace x with x(:) in prctile. The whole matrix will be squeezed in a single vector what will be evaluated just once.
Tom Lane on 9 Feb 2015
I'm not sure this is what you want, but:
a = peaks % 49x49 matrix
b = bsxfun(@plus,a,5*randn(49,49,1000)); % 49x49x1000 matrix
c = prctile(b,95,3); % 49x49 matrix of 95th percentiles