I want to run a loop through a matrix (28x1) that inputs variable from the loop into an expression.

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Jack Gregory 2021-4-23

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回答： Abhas 2024-2-15

I want to run a loop through a matrix (28x1) that inputs variables from the loop into an expression.

I have a matrix that is 28x1. In the matrix I have (1,1), (2,1) as 0. (3:28,1) = 5:5:130

f=w(1:Inp+2,1) It is Inp + 2 because of the two zeros

I have a for loop of i=1:length(f)-1

I want to take the last number (end) multiply it by 2 and add the second to the last number (end-i) and give me an output. Then do the same thing but add the third to the last number(end-i). I want it to run till it hits zero which are the two top variables in the matrix.

I then want it to take the second to last number(end-1) multiply by 2 and add the third to the last number.

and follow the same pattern until 0

Example: I want to input 4

f=(1:6,1)

0

5

10

15

20

The first output is 55 (20*2+15 )

Second 50 (20*2+10)

45 (20*2+5)

40 (20*2+0)

Fith 40 (15*2+10)

35 (15*2 +5)

I would love if It could also do (End+ end-1+end-2) (20+15+10)

For each

The end goal is to know every combination of three variables but only one can repeat. Ex(20*2+5) cannot have (20*3).

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Answer 1

Abhas 2024-2-15

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Hi Jack,

To store all the combinations of every triplets after performing the calculations, you can follow these steps in MATLAB: :

Initialize the matrix 'f' with two zeros followed by values from 5 to 130 in increments of 5.
Iterate over the matrix 'f' in reverse, starting from the last non-zero element.
In each iteration, multiply the current element by 2 and add it to each of the preceding elements, ensuring not to include the initial zeros.
Store the results of these computations in an output array.
Display the final output array containing all calculated combinations.

Here's the MATLAB code to reflect the above steps:

% Initialize the matrix f
f = [0; 0; (5:5:130)'];
% Initialize output array to store the results
output = [];
% Loop through the matrix f for all elements
for idx = 1:length(f)
    % Start with the last element, then move to the second-to-last, and so on
    last_element_index = length(f) - idx + 1;
    
    % Multiply the selected element by 2 and add the preceding elements
    for i = 1:last_element_index-1
        if last_element_index - i > 1 % Ensure we don't include the two zeros
            output = [output; 2*f(last_element_index) + f(last_element_index-i)];
        end
    end
    
end
% Display the output
disp('Output:');
disp(output);

This code will provide you with the output that includes all the combinations as described, ensuring that no element is used more than twice in any sum.