odrpack

odrpack is a package for weighted orthogonal distance regression (ODR), also known as errors-in-variables regression. It is designed primarily for instances when both the explanatory and response variables have significant errors. The package implements a highly efficient algorithm for minimizing the sum of the squares of the weighted orthogonal distances between each data point and the curve described by the model equation, subject to parameter bounds. The nonlinear model can be either explicit or implicit. Additionally, odrpack can be used to solve the ordinary least squares problem where all of the errors are attributed to the observations of the dependent variable.