MATLAB: Interp1 – [Matlab R2016a] – Speed Issues

Question

Heeeey guys,

as I already noticed in this community, I am not alone with that problem. I have tried several solutions proposed in here but it didnt help for reasons like: Old Matlab Versions (interp1 has changed significatly) or another kind of problem.

Let me first tell you what i am doing to make it easier for you to help me:

I a for-loop with approx. 30.000 iterations i use interp1 several time (5 times per iteration – see the profiler below).

Example of the call: [interp1( x, y, xq)]

Here, x is a vector (length 10.000) and y is also a vector (length 10.000) and xq is a vector (length 50.000 or more).

The problem is also that y changes in each iteration and therefore, I cannot precompute any operation (xq is also updated each iteration).

I would be very grateful if you had any suggestions to improve the computational time in this case.

Best regards, Ilya

Answer 1

Test if creating a griddedInterpolant once before the start of the for loop, replacing the Values property of the object each time you change y, is faster.