07 · Inverses and the Pseudoinverse

Part IV, Block 4 of Tensors for Machine Learning. Use one question throughout:

Does an exact inverse exist? If not, what useful answer does the pseudoinverse give us instead?

In machine learning A is almost never square: one row per example, one column per feature, and far more examples than features. The Moore-Penrose pseudoinverse A⁺ is defined for every matrix — square or not, singular or not — and it is computed from the SVD.

This is the first of the three places the workshop’s connecting idea shows up: when a problem has no exact answer and no true inverse, you find the best stable approximation instead.

Study here, then run the real thing: notebook 07 on Colab · the handbook · Kahoot 2

Built from the workshop’s own material by Ravi Kalia and Sebastian Laverde Chunza, CC BY 4.0.