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How can i create a new matrix that equationally depends on another matrix?

Asked by anil hamzacebi on 17 Oct 2019
Latest activity Commented on by Steven Lord
on 18 Oct 2019
i have a 1:1180 matrix that gives me variable velocity values and i need to create a new 1:1180 matrix to get transmission ratios for each velocity value.
i tried something but could not find a way so i am asking here. Please help.

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2 Answers

Answer by Kevin Phung on 17 Oct 2019
Edited by Kevin Phung on 17 Oct 2019
 Accepted Answer

Here's a potential solution:
gear = zeros(1,numel(v)); % initialize gear array
gear(and(v>=0,v<25)) = 1; %logical indexing
gear(and(v>=25,v<50)) = 2;
gear(and(v>=50,v<70)) = 3;
gear(and(v>=70,v<90)) = 4;
gear(v>=90) = 5;)
Note: you should double check my inequalities. Im not sure where you want the bounds to be inclusive.
for example: v>=70 and v<90, versus v>=70 and v<=90
Let me know if this is what you needed

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Answer by Steven Lord
on 17 Oct 2019
Edited by Steven Lord
on 17 Oct 2019

I would use discretize.
% Generate some sample data for this example
v = randi([0, 100], 50, 1);
% Discretize into bins (the second input) with values given by the third input
% The right edge of the last bin should be at least as large as
% the largest element in v
gear = discretize(v, [0; 25; 50; 70; 90; 100], (1:5).');
% Put the sample data and discretized data into a table for easy display
results = table(v, gear);
% Show the first several rows of the results table
head(results)
Depending on whether I was planning to use the gear information for later computation or for reporting to the user, I might create categorical data instead of numeric.
gearCategories = discretize(v, [0; 25; 50; 70; 90; 100], ...
'categorical', ["first"; "second"; "third"; "fourth"; "fifth"]);
resultsCategorical = table(v, gearCategories);
head(resultsCategorical)
The IncludedEdge name-value pair argument may also be useful depending on whether you want 25 to be first or second gear etc.

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Thank you for your great answer!!!
I've tried your code and it's working well. i was not expecting two excellent help these quickly!!
i couldn't mark your respond i guess because that's one shot but i'm writing this comment also going to flag your respond as a solution i think it will help other people
Thank you again and wish you succes!!
Flags are intended to report spam or other problems. [Think of the idea of a red flag.] If you want to indicate to people that this answer helped you even though it isn't the accepted answer, you can leave a comment to that effect (like you did) and/or vote for the answer.
Since this is my answer that got flagged, I'll leave it for someone else to remove the flag.

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