Penalized splines for smooth representation of high-dimensional Monte Carlo datasets

Detector response to a high-energy physics process is often estimated by Monte Carlo simulation. For purposes of data analysis, the results of this simulation are typically stored in large multi-dimensional histograms, which can quickly become both too large to easily store and manipulate and numerically problematic due to unlled bins or interpolation artifacts. We describe here an application of the penalized spline technique [1] to eciently compute B-spline representations of such tables and discuss aspects of the resulting B-spline ts that simplify many common tasks in handling tabulated Monte Carlo data in high-energy physics analysis, in particular their use in maximum-likelihood tting.