Scale 3D matrix by 10i

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Johnny
Johnny on 26 Jan 2014
Answered: Andrei Bobrov on 26 Jan 2014
M = randi([5 10], 1);
N = randi([5 10], 1);
P = randi([20 30], 1);
Y = round(-10 + (10 - (-10)).*rand(M, N, P));
===================================
indexes = 1:P;
scaling = repmat(indexes(:), [M, N, P])
Yscaled = Y.*(scaling.*10)
How I understand this question is that I have to create another 3D matrix and multiple the two (matrix) in order to scale it
How to I create a 3D matric: first page all 1 , second page all 2 , etc up to P

Answers (3)

Image Analyst
Image Analyst on 26 Jan 2014
Edited: Image Analyst on 26 Jan 2014
Hint:
y=cat(3, ones(2), 2*ones(2), 3*ones(2)) % Sample initial data.
[rows, columns, planes] = size(y)
m = 10*(1:planes)
m2 = imresize(m', [numel(y), 1], 'nearest')
y_out = reshape(.......
Finish the last line by yourself and it will be done. imresize() requires the Image Processing Toolbox. Type ver to see if you have it.

Johnny
Johnny on 26 Jan 2014
Edited: Johnny on 26 Jan 2014
% Create a indexes vector
indexes = 1:P;
% Make indexes array into individual pages
n = reshape(indexes,1,1,P)
% Create a 3-dimensional matrix from indexes vector
m = repmat(n,M,N)
% Elementwise multiplication between matrix m and Y
Yscaled = Y.*(m.*10)
  1 Comment
Amit
Amit on 26 Jan 2014
Very nice. You're getting a hang of MATLAB.

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Andrei Bobrov
Andrei Bobrov on 26 Jan 2014
Yscaled = bsxfun(@times,Y,reshape(1:P,1,1,[])*10)

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