Adding numbers to specific matrix index.
显示 更早的评论
i want to fill in a 100x100 matrix using a nested for loop. However for each ’i’ row there will only be 3 ‘j’ columns with nonzero numbers. Also i want leave the first and last row all zeros. This is what ive tried before and its not working. what am i doing wrong?
A = zeros(100,100);
h = 1;
for i = 2:99;
for j = 2:99;
A(i, j+1) = ((1/h) + i);
A(i, j) = (-2/h);
A(i, j-1) = ((1/h) - i);
end
end
%so after one iteration i would have the values at the given indices
% %A(2,3) = 3
%A(2,2)=-2
%A(2,1)=-1
采纳的回答
Geoff Hayes
2019-3-6
However for each ’i’ row there will only be 3 ‘j’ columns with nonzero numbers How do you determine which three columns of the ith row are non-zero? In your above example, for the second row, the first three elements are non-zero. Does this mean that in the third row, the 2-4 columns are non-zero? In which case you would do something like
A = zeros(100,100);
h = 1;
for i = 2:99;
A(i, i+1) = ((1/h) + i);
A(i, i) = (-2/h);
A(i, i-1) = ((1/h) - i);
end
Or are you trying to do something else?
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
