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# 3d correlation

## 3d correlation

(OP)
I am trying to compute the correlation coefficient between two 3d matrices. Specifically, i am trying to compare a simulated model's efficiency with given input torques and speeds to a bench efficiency test at given torques and speeds.

I can go in and pick out several points determine the correlation but being there are hundreds of points in both data files, i'd rather use a function to look at the entire data set.

Is there a function in matlab that allows this kind of computation?

Example of the data would be in this format (I have thousands of data points in each data file however).

Speed Torque Efficiency
600 500 .95
700 550 .96

### RE: 3d correlation

(OP)
I should also note that the bench data is at fixed interval speed and torque points whereas the simulated data is not, so I would be looking for a function that allows interpolation.

### RE: 3d correlation

Define a new regular grid of rpm vs torque. Interpolate you sim data and test data (separately) onto that grid. run whatever stats you like for goodness of fit at those grid points.

Matlab's rather inelegant surface fitting tools are here https://au.mathworks.com/help/curvefit/fit.html . There are alternatives at the file exchange.

Cheers

Greg Locock

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### RE: 3d correlation

"mahal" procedure. (Mahalanobis distance) Use this function to compute a confidence ellipsoid.

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