help with summing array (sigma sigma)
5 views (last 30 days)
Show older comments
Q Write a m-file e74.m that generates a random matrix A that is always 200 in width, and calculates the sum Σ Σ Where A is of width 200 and height H. The file e74.m should use a nested for-loop (two for loops nested in each other).
sorry for the previous incorrect format
this is what i have so far..... Better?
SumOfNumbers=0
SumOfNumbers= SumOfNumbers + A(j,k)^2
[rows,columns] = Size(A)
for j=1:200 % row index
for k=1:n % column index
disp(A(k,j))
end
0 Comments
Answers (1)
Image Analyst
on 15 Jun 2013
Huh? You have 3 for loops instead of two (one over rows and one over columns). What is the loop over n for? Plus, you aren't doing any summing at all! Where is the sum line, like theSum = theSum + A(k,j)????
Next, the width is 200 columns ( not the height), so why are you iterating over 200 rows instead of 200 columns?
Please read this to learn how to format your code:
2 Comments
Image Analyst
on 15 Jun 2013
Edited: Image Analyst
on 15 Jun 2013
Regarding your edit: you don't need the first 3 lines. You need another end to finish the first for loop, and you need a summing line like I already told you, plus you need to initialize theSum to zero before the loops. Plus your for loop limits are wrong. Hint:
[rows, columns] = size(A)
Use rows and columns in the for loop.
Image Analyst
on 15 Jun 2013
Getting better, but you still didn't read my comment above because you haven't implemented most of the fixes I told you. Please read it again and do some of the things - all of them actually.
See Also
Categories
Find more on Creating and Concatenating Matrices in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!