Write Whole Arrays or Strings

The general guidelines about array use discussed in Use Arrays Efficiently also apply to reading or writing an array with an I/O statement.

To eliminate unnecessary overhead, write whole arrays or strings at one time rather than individual elements at multiple times. Each item in an I/O list generates its own calling sequence. This processing overhead becomes most significant in implied-DO loops. When accessing whole arrays, use the array name (Fortran 95/90 array syntax) instead of using implied-DO loops.