I-spline

In the mathematical subfield of numerical analysis, an I-spline[1][2] is a monotone spline function.

A family of I-spline functions of degree k with n free parameters is defined in terms of the M-splines Mi(x|k, t) where L is the lower limit of the domain of the splines.

Since M-splines are non-negative, I-splines are monotonically non-decreasing.

Otherwise, I-splines can be used as basis splines for regression analysis and data transformation when monotonicity is desired (constraining the regression coefficients to be non-negative for a non-decreasing fit, and non-positive for a non-increasing fit).

This applied mathematics–related article is a stub.