CONVERSION TO FORTRAN-90 - A CASE-STUDY

The features of the new standard language Fortran 90 are introduced an d discussed. In order to focus the discussion, the particular context is the conversion of an existing published ACM Transactions on Mathema tical Software algorithm from Fortran 77 to the new standard. Emphasis is on the new features of the language, including the array facilitie s, the use of modules, the applicability of user-defined (-derived) da ta types, the reduction in machine dependence of numeric codes, and th e dynamic allocation of storage. The intent is that writers of softwar e as well as those who use Fortran in scientific and engineering work will find this a helpful introduction to the new and powerful features of Fortran 90.