InterpolatingFunction.Integrate(f) integrates f over the interval on which f is defined
InterpolatingFunction.Integrate(f,a,b) integrates f from a to b where a and b must be within the interval on which f is defined
integration is exact up to floating point precision
f = InterpolatingFunction.Spline({1,2,3},{1,4,9}) print(InterpolatingFunction.Integrate(f)) print(InterpolatingFunction.Integrate(f,1.5,2.5))