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Multiple specific elements in an array

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rockstar49
rockstar49 on 20 Feb 2020
Commented: rockstar49 on 20 Feb 2020
I have a matrix [a b c d e f g]. I want to sum [2*(a + b) + 3*(c+d) +4*(e+f)]. How do i go about doing this ?

Answers (1)

Bhaskar R
Bhaskar R on 20 Feb 2020
Assuming a, b,c, d, ..g are values in the vector say X
X = 1:7;
sum([2:4].*[sum(reshape(x(1:6), 2,3))]);
  5 Comments
Bhaskar R
Bhaskar R on 20 Feb 2020
No, I mean to say that you have asked for "sum [2*(a + b) + 3*(c+d) +4*(e+f)]" then asking for "Now i want to sum 2*.36 + 3*(.14 + .13 +.12 +.1 +.09) +4*(.04 +.02)". Each time we can't change the evaluation of the statement. If there are only less than 10 entries you can write complete statement without using any commands using matlab indexing.
for this
sum 2*.36 + 3*(.14 + .13 +.12 +.1 +.09) +4*(.04 +.02) =
res = sum([2*x(1), 3*x(2:6), 4*x(7:8)]);
I think i am clear!
rockstar49
rockstar49 on 20 Feb 2020
thank you! I did not know of this.
Best,
Zakir M

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