=============
Introduction
=============
Inversion is a huge field in geophysics and elsewhere. Here, we will focus on the least-square solutions which are common but by no means the only methods that can be applied. There are much online resources around such as

* `Examples from Earth Inversion <https://www.earthinversion.com/geophysics/least-squares-method/>`_

* `Examples from Simpeg.xyz <https://docs.simpeg.xyz/content/tutorials/02-linear_inversion/plot_inv_1_inversion_lsq.html>`_


and also classic textbooks such as:

* `William Menke: Inverse Theory <https://www.sciencedirect.com/book/9780123971609/geophysical-data-analysis-discrete-inverse-theory>`_

We will not reiterate all the known theory in this blog, but we do have videos leading you through some main concepts of the mathematical jungle. The biggest distinction to be made is about the linearity/non-linearity of your forward model. You also need to know if your problem is over- or underdetermined. Regularization can be naturally included, but we did not cover this in the 2023 course.