** 2-D biharmonic data interpolation and gridding. **

** ZI = INTERP3(X,Y,Z,XI,YI) uses biharmonic interpolation to **

** find ZI, the values of the underlying 2-D function in Z at the points **

** in matrices XI and YI. Matrices X and Y specify the points at which **

** the data Z is given. X and Y can also be vectors specifying the **

** abscissae for the matrix Z as for MESHGRID . In both cases, X **

** and Y must be equally spaced and monotonic. **

** **

** **

** If X, Y, and Z are all vectors, INTERP3 interpolates within the **

** data given by the (possibly irregularly spaced) ordered triplets **

** (X,Y,Z) to return matrix ZI. **

** **

** **

** ZI = INTERP3(Z,M,N) returns an M-by-N matrix ZI whose values **

** are interpolated within matrix Z. **

** **

** **

** [ZI,WEIGHTS]=INTERP3(X,Y,Z,XI,YI) also returns the computed **

** interpolation WEIGHTS, which can be reused as follows: **

** INTERP3(X,Y,Z,XI,YI,WEIGHTS) uses the given WEIGHTS vector, **

** instead of recalculating them from X, Y, and Z. **

** **

** **

** INTERP4 and INTERP5 are much faster than INTERP3 for **

** data interpolation and should be used unless irregularly **

** spaced vector triplet gridding is required. **

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** **

** See also INTERP4 , INTERP5 , INTERP2 , SPLINE , INTERP1 . **

** **