在MATLAB中的指定轴上插补

Question

I have an n-dimensional matrix, funtointerpolate , and I wish to perform one dimensional interpolation along one of its axes (let's call it axis m ). In Python, interpolate functions such as interp1d allow one to specify the axis of interpolation. In MATLAB, I cannot see an obvious way to do this using interp1 or any other built-in interpolate functions. Ideally, the function would look something like

interpolatedfun = interp1(funtointerpolate,oldpoints,newpoints,axis = m)

An obvious way to get around this is to loop over all the other axes in funtointerpolate , but this is rather cumbersome. The motivation for interpolation is that the data in funtointerpolate is evaluated along a non-uniform grid along the m axis. I need it to be uniform along m . Mathematically, suppose I have some tensorial object

A_{ijk}

which is evaluated along a non-uniform grid along the j index. Then, I wish to find a new A such that the jth index consists of values evaluated on a uniform grid. I know the new uniform grid for the jth index, newpoints , and the old grid oldpoints .

Answer 1

You can use the interpn function for this purpose:

newV = interpn(oldAx1, ..., oldAxM, ..., oldAxN, oldV, ...
               oldAx1, ..., newAxM, ..., oldAxN);

where V is your output.

(Of course the above is pseudo-code, but it should nicely illustrate the way to solve your problem.)