A computational tool that determines the best-fit solution to an overdetermined system of linear equations by minimizing the sum of the squares of the residuals is essential in many scientific and engineering disciplines. This method addresses scenarios where there are more equations than unknowns, and no exact solution exists. For instance, consider a scenario involving fitting a curve to experimental data; the data points represent the equations, and the parameters of the curve represent the unknowns. The process seeks to find parameter values that minimize the discrepancy between the predicted curve and the actual data points.
This approach offers significant advantages in various fields. In statistical modeling, it provides unbiased estimates of parameters when certain conditions are met. In signal processing, it enables the reconstruction of signals from noisy data. Furthermore, this technique has a rich historical background, with its development tracing back to the work of Carl Friedrich Gauss in the early 19th century. Its continued use and refinement underscore its enduring utility and the reliable solutions it provides.