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How to use mathematical constants?

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Old   January 19, 2016, 06:05
Default How to use mathematical constants?
  #1
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ArielJ
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Hi everyone! Ok very simple question here but oddly I can't find an answer that works!

I am using codeStream in my blockMeshDict file and one of the things I'm trying to calculate involves multiplying by pi...oddly though, I can't seem to use pi correctly. (I have left in #calc and $r1 in the examples just to demonstrate the sort of thing I have in my blockMeshDict)

I have so far tried:

Code:
#calc pi*$r1
#calc \pi*$r1
#calc Pi*$r1
#calc mathematicalConstant::pi*$r1
Apologies for what is probably a stupid question!
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Old   January 19, 2016, 09:17
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Alexey Matveichev
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Hi,

And why not:

Code:
constant::mathematical::pi
?

Though for example

Code:
degToRad(180)
would be shorter

Also here is excerpt from $FOAM_SRC/OpenFOAM/global/constants/mathematical/mathematicalConstants.H (just for reference)

Code:
namespace Foam
{
namespace constant
{
namespace mathematical
{
...
    const scalar pi(M_PI);
    const scalar twoPi(2*pi);
    const scalar piByTwo(0.5*pi);
...
} // End namespace mathematical
} // End namespace constant
} // End namespace Foam
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Old   January 12, 2022, 04:58
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Other stuff like, should work too:

Code:
M_PI_2        /* pi/2 */
M_PI_4        /* pi/4 */
M_1_PI        /* 1/pi */
M_2_PI        /* 2/pi */
M_2_SQRTPI    /* 2/sqrt(pi) */
Any particular reason to group some variables inside a particular namespace? Wouldn't it be better to just use the standard stuff in the math.h ?
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