Scattered data 4D interpolation

Dear Sir/Madam

I have following type of data

%        X1         X2        X3       X4     V
        
XV = [
         0         0         0         0   -1.5474
         0         0         0    0.0010   -1.5392
         0         0    0.5000    0.0010   -1.5360
         0         0    0.5000         0   -1.5422
         0         0    1.0000         0   -1.5501
         0         0    1.0000    0.0010   -1.5503
         0    0.5000    1.0000         0   -1.5393
         0    0.5000    1.0000    0.0010   -1.5447
         0    0.5000    0.5000    0.0010   -1.5518
         0    0.5000    0.5000         0   -1.5481
         0    0.5000         0         0   -1.5366
         0    0.5000         0    0.0010   -1.5479
         0    1.0000         0         0   -1.5561
         0    1.0000         0    0.0010   -1.5362
         0    1.0000    0.5000    0.0010   -1.5335
         0    1.0000    0.5000         0   -1.5360
         0    1.0000    1.0000         0   -1.5531
         0    1.0000    1.0000    0.0010   -1.5531
    0.5000    1.0000         0         0   -1.5620
    0.5000    1.0000         0    0.0010   -1.5449
    0.5000    1.0000    0.5000    0.0010   -1.5646
    0.5000    1.0000    0.5000         0   -1.5419
    0.5000    1.0000    1.0000         0   -1.5450
    0.5000    1.0000    1.0000    0.0010   -1.5339
    0.5000    0.5000    1.0000         0   -1.5477
    0.5000    0.5000    1.0000    0.0010   -1.5280
    0.5000    0.5000    0.5000    0.0010   -1.5421
    0.5000    0.5000    0.5000         0   -1.5505
    0.5000    0.5000         0         0   -1.5504
    0.5000    0.5000         0    0.0010   -1.5418
    0.5000         0         0         0   -1.5450
    0.5000         0         0    0.0010   -1.5421
    0.5000         0    0.5000    0.0010   -1.5503
    0.5000         0    0.5000         0   -1.5447
    0.5000         0    1.0000         0   -1.5448
    0.5000         0    1.0000    0.0010   -1.5392
    1.0000         0         0         0   -1.5534
    1.0000         0         0    0.0010   -1.5334
    1.0000         0    0.5000    0.0010   -1.5447
    1.0000         0    0.5000         0   -1.5444
    1.0000         0    1.0000         0   -1.5310
    1.0000         0    1.0000    0.0010   -1.5564
    1.0000    0.5000    1.0000         0   -1.5533
    1.0000    0.5000    1.0000    0.0010   -1.5422
    1.0000    0.5000    0.5000    0.0010   -1.5275
    1.0000    0.5000    0.5000         0   -1.5445
    1.0000    0.5000         0         0   -1.5558
    1.0000    0.5000         0    0.0010   -1.5363
    1.0000    1.0000         0         0   -1.5423
    1.0000    1.0000         0    0.0010   -1.5563
    1.0000    1.0000    0.5000    0.0010   -1.5506
    1.0000    1.0000    0.5000         0   -1.5448
    1.0000    1.0000    1.0000         0   -1.5501
    1.0000    1.0000    1.0000    0.0010   -1.5563
    ];

X1,X2,X3, and X4 are independent variables, and V is dependent one. How can I interpolate the data?

Most of methods I saw for scattered data interpolation only work for 2D and 3D.

Answer 1

[Voss]

https://www.mathworks.com/help/matlab/ref/griddatan.html

Answer 2

[Walter Roberson]

What interpolation do you need?

For example you could do knnsearch() asking for the 2 nearest neighbours of each query point, and do linear interpolation for each.