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Old   October 1, 2001, 15:50
Default double double
  #1
Damir
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How can one make "double" two times longer (more accurate) in C++ in fast way?
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Old   October 1, 2001, 15:57
Default Re: double trouble
  #2
johnny
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do you mean quad. precision?
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Old   October 1, 2001, 16:39
Default Re: double trouble
  #3
Damir
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Yes. I mean quad. precision.
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Old   October 1, 2001, 19:14
Default Re: double trouble
  #4
johnny
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Sorry, I try and stay away from quad precision :P I heard mathmatica can do quad precision fairly easily.

Anyway, I did a web search and get tons of references to c++ "precision" libraries.

Here's a link to one which looks good to me

http://www.nersc.gov/~dhbailey/mpdist/mpdist.html

Cheers
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Old   October 1, 2001, 19:40
Default Re: double double
  #5
Axel Rohde
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I don't know about C++, but 'double precision' in modern programming languages (e.g. Visual Basic) implies 64-bit, which is known in assembly as a 'quad word' (4*16-bit). The older Fortran codes, such as Plot3D, only use 32-bit precision ('double word') for floating point numbers. So 'double double precision' in Fortran may be equivalent to 'double precision' in C++.
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Old   October 1, 2001, 22:47
Default Re: double trouble
  #6
Damir
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Many thanks.
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