MATLAB: Calculating maximum error

errorfunctionMATLABmaxmaximumvectorvectors

I created an vector in matlab that represents an object moving at a velocity v(t) = 5 + 7*t^2 starting from the position x(2) = 5 at t = 2. This vector is called x and is: x2 + 5*t + 7*t.^3/3 (x2 equals 5) (this vector was solved analytically, i.e. I just integrated the velocity function. The next vector, called xtrap, was created using MATLAB's cumtrapz function: xtrap = cumtrapz(t,v) + x2.

How do I calculate the maximum error between these two solutions? Thanks.

Best Answer

   max(abs(x-xtrap))

If you want to know which index in the vector was the largest difference

    [maxdiff,Index] = max(abs(x-xtrap));

Another way is

 norm(x-xtrap,Inf)

but that way, you don't get the index

Related Solutions

MATLAB: How to make multiple max in elegant way

you could do

max(max([ x1 x2 x3 x4 x5 .... ]))

Since the first max is evaluated along the columns, I think it should be fast enough. Alternatively, you could of course do X = [ x1 x2 x3 ... ] and then max(X(:)). That's shorter, but depending on the length of your vectors, I would go with the first option. A common alternative is to use sort, e.g.

X_sorted = sort([ x1 x2 ... ]);
xmax = max(X_sorted(end,:))

but since for max, you don't need the matrix to be fully sorted, I would guess that max is actually faster.

MATLAB: How to know the location of maximum value in a vector

doc max
[value,index] = max(A);

Best Answer

Related Solutions

MATLAB: How to make multiple max in elegant way

MATLAB: How to know the location of maximum value in a vector

Related Question