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How to vectorize a matrix?

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Sky Scrapper
Sky Scrapper on 8 Jan 2019
Commented: Sky Scrapper on 14 Jan 2019
Dear All,
I have a matrix of 90x12. I need to use 2D look up table for matlab simulink. There i will have to put the vector of input values. That means, Vector for input values x:
[0 1 2 3 4 .........89] and vector for input values 'y': [0 1 2 3 4 5 6 ..11]. How can I write a code that will take the values for x and y automatically with the desired length?
Thanks!

  1 Comment

Fangjun Jiang
Fangjun Jiang on 8 Jan 2019
Not clear. Don't understand the question.

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Accepted Answer

OCDER
OCDER on 8 Jan 2019
%Starting input
M = reshape(1:90*12, 90, 12); %your 90x12 lookup matrix
X = [0 1 3 4 89]; %input X lookup
Y = [0 1 3 5 11]; %input Y lookup
%Matlab does NOT use 0-based index. So add 1.
X = X+1;
Y = Y+1;
%Use sub2ind to to convert (X,Y) to a linear index.
Idx = sub2ind(size(M), X, Y);
%Collect your value based on index X and Y
Value = M(Idx);
In short, the above can be simplified as:
M = reshape(1:90*12, 90, 12); %your 90x12 lookup matrix
X = [0 1 3 4 89]; %input X lookup
Y = [0 1 3 5 11]; %input Y lookup
Value = M(sub2ind(size(M), X+1, Y+1));

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Sky Scrapper
Sky Scrapper on 14 Jan 2019
If I am writing: A= 0 : size (B,1) %B is my matrix of 89x8
now it's showing: 0,1 ,2 .......................89
But I need: 0,1,2 ............................88
How to do this?
Stephan
Stephan on 14 Jan 2019
A = 0:size(B,1)-1
Sky Scrapper
Sky Scrapper on 14 Jan 2019
oh i see. i tried: A= 0 : size ((B-1),1)).
I had little bit misunderstanding. thank you very much!

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