Experiences (continued)
The transition from the J90 to the SV1A was seamless.
Although FORTRAN90 is backward compatible with FORTRAN77, differences between the compilers necessitated some minor changes to the code.
Some sections of the code benefited from being rewritten to take advantage of FORTRAN90 features, e.g. the Poisson solver used to compute the initial condition using FORTRAN90 array syntax is over four times faster than the FORTRAN77 version.