addition , subtraction

[EDIT: 20110519 14:45 CDT - reformat - WDR]

Hi, I need help in coding the following example.. thanks

S is (mXn) matrix and d is (mX1) array

S(1,:) = [0 0.2 0.3 0.5 0.6 0.7 0.72 0.75 ...... 1 ]

for example length(S(1,:)) = odd (lets say 7)

d(1)= S(1,1) + (S(1,3)-S(1,2))+(S(1,5)-S(1,4))+(S(1,7)-S(1,6))

...and so on...

if length(S(1,:)) = even(lets say 8)

d(1)=S(1,1) + (S(1,3)-S(1,2))+(S(1,5)-S(1,4))+(S(1,7)-S(1,6))

i.e. neglect S(1,8)

I want to run this program in a loop for entire S matrix and find the array d

Answer 1

[Walter Roberson]

d = Sum(S(:,1:2:end),2) - Sum(S(:,2:2:end-1),2)

[Andy]

Ninja'd! Walter, you need lower case sums.

[Walter Roberson]

Good point, Andy. I've been flipping between programming languages too much.