Matrix integral over layers

3 次查看(过去 30 天)
Lev Mihailov
Lev Mihailov 2020-7-17
Hello! I have a matrix in it the number of steps per time. Is it possible to integrate each column of the matrix layer by layer (layer sizes may differ)
MatrixHelpStep=rand(30,40);
layer=(1:5:30); % for example, I took layer 5 (but it can change)
% trying to create a loop for layers
for i=1:length(layer)-1
Imhs=trapz(MatrixHelpStep(layer(i):layer(i)+1))
end
it gives me only one value
  4 个评论
Walter Roberson
Walter Roberson 2020-7-17
Could you confirm that you want overlap? trapz(x(1:5,1)) uses 5 elements to form the output, but trapz(x(5:10,1)) uses 6 elements to form the output. Are you wanting 1:5, 6:10, 11:15, 16:20 and so on?
Lev Mihailov
Lev Mihailov 2020-7-17
yes, I want such overlaps

请先登录,再进行评论。

回答(1 个)

Bjorn Gustavsson
Bjorn Gustavsson 2020-7-17
For this I would try cumtrapz - it calculates the cumulative (sp?) trapezoidal integral in the same manner as cumsum calculates the cumulative sum along an array. Doing that would give you the cumulative integrals of your matrix with the same size as your matrix. That way you can easily calculate every following integral between 2 boundaries from that one just by taking the difference between the corresponding boundary-elements. Something like this:
I = peaks(40);
I = I(1:30,:);
ciI = cumtrapz(I);
i10to17ofI = ciI(17,:) - ciI(10,:);
HTH

类别

Help CenterFile Exchange 中查找有关 Loops and Conditional Statements 的更多信息

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by