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CFX 64bit single-double precision

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Old   December 19, 2006, 15:40
Default CFX 64bit single-double precision
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Hi. I am running CFX in a 64bit computer. But am having difficulty understanding what the difference between the single and double precision option is using CFX.

Is single and double still 8 and 16 decimal places respectively on a 64 bit computer?


Does it increase to 16 and 32 decimal places for single and double precision respectively?

Thanks for your help.
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Old   December 19, 2006, 16:01
Default Re: CFX 64bit single-double precision
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Single and double precision still means 8 resp. 16 digit precision for floating point numbers.

The 32 resp. 64 bit computers differ in the size of their virtual memory.
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Old   December 19, 2006, 16:39
Default Re: CFX 64bit single-double precision
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To add to that, AFAIK x86 CPU's (both IA-32 and AMD64) actually do the maths in 80 bits, it's just a question of how much precision gets stored. So double precision is not primarily slower because of processing at higher precision, but rather because of the extra amount of information that has to be stored and retrieved from memory.
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