MATLAB: Numerical integration in matlab

numerical integration

Suppose A is a column vector whose arrays are acceleration of a moving object and each array has been sampled every 0.01 sec.

I want to numerically integrate A to evaluate the velocity time history of object. I did the following:

t = (0 : 0.01 : 0.01 * (length(A) - 1));%time as a column vector
V = zeros(size(A));%initiate velocity vector
for ii = 1 : length(A) - 1
    V(ii+1) = V(ii) + trapz(t(ii:ii+1),A(ii:ii+1));
end

The above code works well but I have hundereds of acceleration vectors and peforming calculation using "for loop" is too much time consuming.

Is there any function in matlab to integrate without "for loop" over vectors?

Best Answer

cumtrapz()

Related Solutions

MATLAB: Help using loop and range interval

v = randi([0,30],60,1); % Let your data
k0 = 0.5*1.29*9.62;
c = [0;.4;.2;.1;.001];
k = [-inf;3;10;14;25;inf];
[~,b] = histc(v,k);
model = k0*v.^3.*c(b);

with loop for..end

n = numel(v);
model = zeros(n,1);
k0 = 0.5*1.29*9.62;
for ii = 1:n
    if v(ii) < 3
        cp = 0;
    elseif v(ii) >=3 && v(ii) < 10
        cp = 0.4;
    elseif v(ii) >= 10 && v(ii) < 14
        cp = 0.2;
    elseif v(ii) >= 14 && v(ii) < 25
        cp = 0.1;
    elseif v(ii) >= 25
        cp = 0.001;
    end
    model(ii) = k0*v(ii).^3*cp;
end

MATLAB: Finding the Velocity at Different intervals

You can solve the problem of varying numbers of elements in each iteration by using cell arrays for ‘v’ and ‘d’:

for ii = 1:11   
    v{ii} = trapz(a(1:ii),k);
end
% calculate the displacement d at each time interval
for jj = 1:11 
    d{jj} = trapz(v{jj},k);
end

The best solution would likely be to use the cumtrapz function instead, and avoid the loops entirely.

Best Answer

Related Solutions

MATLAB: Help using loop and range interval

MATLAB: Finding the Velocity at Different intervals

Related Question