Fagan, Mike2018-06-182018-06-182006-12Fagan, Mike. "Derivatives By-Address for Fortran 77." (2006) <a href="https://hdl.handle.net/1911/102065">https://hdl.handle.net/1911/102065</a>.https://hdl.handle.net/1911/102065FIXME. Automatic differentiation tools use 1 of 2 strategies to access derivative values. These strategies are: By-address, By-name. The by-address method is typically implemented by introducing structured types for each active scalar type. For example, scalar type 'real' will have an associated structure type 'active-real'. Using this strategy, all active variables types are changed to the associated structured type. On the other hand, the by-name method introduces an associated new variable for each active variable. For example, the derivatives associated with 'pressure' would be 'd_pressure'. Since the by-address strategy employs structured types, AD tools for Fortran 77 have not employed that strategy. In this paper, we show how to use array access to implement the by-address strategy for Fortran 77. We discuss the canonicalization issues, outline our Adifor3.0 implementation of this technique, and give a few sample performance6 ppengTechnical reportTR06-20