splinesBasis: Evaluating splines basis functions
In ivmte: Instrumental Variables: Extrapolation by Marginal Treatment Effects

This function evaluates the splines basis functions. Unlike the bSpline in the splines2 package, this function returns the value of a single spline basis, rather than a vector of values for all the spline basis functions.

1	splinesBasis(x, knots, degree, intercept = TRUE, i, boundary.knots = c(0, 1))

`x`	vector, the values at which to evaluate the basis function.
`knots`	vector, the internal knots.
`degree`	integer, the degree of the splines.
`intercept`	boolean, default set to `TRUE`. This includes an additional component to the basis splines so that the splines are a partition of unity (i.e. the sum of all components equal to 1).
`i`	integer, the basis component to be evaluated.
`boundary.knots`	vector, default is `c(0, 1)`.