Moore-Penrose pseudoinverse

See Wikipedia: Moore–Penrose pseudoinverse.

Some of its properties are explained in the following pages:

• Tenney-Euclidean tuning
• Dave Keenan & Douglas Blumeyer's guide to RTT/Tuning computation#Pseudoinverse method
• Generator embedding optimization#Pseudoinverse: the "how"
• Generator embedding optimization#Pseudoinverse: the "why"