Model fitting by least squares |
Define the residual and the ``size'' of any vector, such as the data vector, as . The number is called the ``success at fitting data.'' (Any data-space weighting function should have been incorporated in both and .)
While the data fitting success is of interest to everyone, the second number is of interest in QA (quality analysis). In giant problems, especially those arising in seismology, running iterations to completion is impractical. A question always of interest is whether or not enough iterations have been run. This number gives us guidance to where more effort could be worthwhile.
Fitting success: Numerical success: |
Model fitting by least squares |