Partial derivatives of a 3D array with unevenlyspaced entrys in Matlab

Dear all

I am new to Matlab and to be honest a little rusty in general when it comes to handling numerical Data in an environment like Matlab.

I´ll start off with a very general description of what i want to achieve. I have a few 3D Matrix with the Size of 167x176x2000 Datapoints. The Data is from a physical measurement and unfortunately the datapoints are not evenly spaced in all of these Datasets. In some the are. I want to calculate the partial derivative of this 3D dataset in an arbitrary direction. The Vector would always be parallel to the xy-Plane, albeit not necessarily to the x- or y-Axis.

Could you point me in the right direction regarding this enterprise? Do i need to make a Spline-Fit in the direction of the derivate before i perform the actual derivation? Which method is delivering the best restult? The derivates needs to be as "good" as possible so i feat a first order central difference might not be good enough.

For all these data sets there already exists a closely related Matrix which i´d like to use to "draw" the direction of the actually desired derivate as these additional Matrix shows some topological features wich i want to related to the derivate to be computet. Is this possible?

All the best

I would really appreciate all the input you could give me

NorrinRad

Answer 1

[Bernd Ab]

Hello

Maybe i should brake my question into pieces. My first problem is how to make partial derivatives in an arbitrary direction? I know the Diff kommand, but i do not understand how to use it for an arbitarry direction?

Thanks in advance

NorrinRadd