CODEWITHSUNDEEP
matlabloops
Shaibal Ahmed
Shaibal Ahmed

Reputation: 189

Loop with separate iterations in MATLAB

I want to calculate the variable h with the following system of equation in MATLAB. What could be a proper way to write it?

h(1) = 1 - z(1);
h(2) = 1 - h(1) - z(2);
h(3) = 1 - h(1) - h(2) - z(3);
h(4) = 1 - h(1) - h(2) - h(3) - z(4);
h(5) = 1 - h(1) - h(2) - h(3) - h(4) - z(5);
h(6) = 1 - h(1) - h(2) - h(3) - h(4) - h(5) - z(6);

Upvotes: 1

Views: 57

Answers (2)

Suever
Suever

Reputation: 65460

You can accomplish this with diff which takes the difference between any two elements.

z = [1 4 5 7 8 3];

h = [0 -diff(z)];
%     0    -3    -1    -2    -1     5

How we determine to use diff is that we can easily write out the terms and see that most things cancel

h(2) = 1 - h(1) - z(2)
h(2) = 1 - (1 - z(1)) - z(2)
h(2) = 1 - 1 + z(1) - z(2)
h(2) = z(1) - z(2)

Upvotes: 4

zglin
zglin

Reputation: 2919

The below code should mostly work. The trick is to setup an array with z in it. 

h=[]% empty array
h(1)=1-z(1)
for counter=2:N
    h(counter)=1-cumsum(diff(h(1:counter-1)))-z(counter)

end

Upvotes: 0

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