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Re: real*8 declarations for variables using g77
- From: dominiq at lps dot ens dot fr (Dominique Dhumieres)
- To: fortran at gcc dot gnu dot org
- Cc: Philip dot J dot Dumont at jpl dot nasa dot gov, tobias dot schlueter at physik dot uni-muenchen dot de
- Date: Mon, 01 Dec 2008 21:04:09 +0100
- Subject: Re: real*8 declarations for variables using g77
Tobi,
> your question is off-topic, but the answer is 'yes'. REAL*8 is a non-standard synonym for DOUBLE PRECISION.
I am not sure to fully agree with you. If I remember correctly, in the standard DOUBLE PRECISION
is twice the size of the default REAL. For instance in the old time of the CRAY glory, REAL
was 8 bytes, hence DOUBLE PRECISION was 16 bytes (implemented in software, leading
to a dramatic increase in the execution time). Nowadays, the usage has more or less
settled to REAL==4 bytes==REAL*4==REAL(4ÂÂ), while
DOUBLE PRECISION==8 bytes==REAL*8==REAL(8).
Dominique