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Next: Consequences of the Up: The FORALL Statement Previous: Examples of the

Scalarization of the FORALL Statement

One way to understand the semantics of the FORALL statement is to exhibit a naive translation to scalar Fortran 90 code. We provide such a translation below.

• []Advice to implementors. Note, however, that such a translation is meant for illustration rather than as the definitive reference to the FORALL semantics of or practical implementation in the compiler. In particular, implementing a FORALL using DO loops imposes an apparent order on the operations that is not implied by the formal definition. Additionally, compiler analysis of particular cases may allow significant simplification and optimization. For example, if the array assigned in a FORALL statement is not referenced in any other expression in the FORALL (including its use in functions called from the FORALL), it is legal and, on many machines, more efficient to perform the computations and final assignments in a single loop nest. Also note the discussion at the end of this section regarding other difficulties of a Fortran 90 translation. (End of advice to implementors.)

A forall-stmt of the form

_=13_}