Re: COMPUTATIONAL FLUID DYNAMICS - Help with SIMPLE algorithm implementation

Stuart GRAHAM wrote:

>
> By how much does having the loops look like this speed it up?
>
> DO 60 I=0,N+1
> DO 60 J=0,M+1
> U(J,I)=0.d0
>


I agree with Glen and Tim that this can speed up such loops
tremendously, but you might not necessarily see it on your system.
Many optimizers can perform the appropriate loop interchange,
especially in simple cases like the above. However, in fact, I view
this as a good reason for writing the loops the `correct' way round -
it stops you wondering why the code runs so slowly in your new system,
where the compiler does not alter the loop order,

Ian

.

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