The computation of points or values between ones that are known or tabulated using the surrounding points or values.
In particular, given a univariate function, interpolation is the process of using known values to find values for at points , . In general, this technique involves the construction of a function called the interpolant which agrees with at the points and which is then used to compute the desired values.
Unsurprisingly, one can talk about interpolation methods for multivariate functions as well, though these tend to be substantially more involved than their univariate counterparts.
, interpolation is the process of using known values 
to find values for 
at points 
, 
. In general, this technique involves the construction of a function 
called the interpolant which agrees with 
at the points 
and which is then used to compute the desired values. 