| Article ID: | iaor2001992 |
| Country: | Germany |
| Volume: | 87 |
| Issue: | 2 |
| Start Page Number: | 209 |
| End Page Number: | 213 |
| Publication Date: | Jan 2000 |
| Journal: | Mathematical Programming |
| Authors: | Broyden C.G. |
This short note traces the events that led to the unsymmetric rank one formula known as the ‘good Broyden’ update, which is widely used within derivative-free mathematical software for solving a system of nonlinear equations.