what does the function min() do???

sven · November 9, 2009, 19:54

Somewhere in the source Code of a turbulence model I found something which I dont understand. Unfortunately the understanding of this line is crucial to what I am doing. The line I am talking about is

Code:

P[faceCelli] *=
                    min(G[faceCelli]/(0.5*mag(tr(P[faceCelli])) + SMALL), 1.0);

What I dont understand are the following things:

what is SMALL? A variable a function??
what does the function min do? Does it select eitherG[faceCelli]/(0.5*mag(tr(P[faceCelli])) + SMALL) or 1.0, depending on which value is the smaller one

If I do some more source Code searching, I find

Code:

inline retType min(const type1 s1, const type2 s2) \
{                                                  \
    return (s1 < s2)? s1: s2;                      \
}

Can someone understand this?

Thank you very much!

Simon Lapointe · November 9, 2009, 21:41

Hi,

min(a,b) returns the smallest value between a and b. SMALL stands for a small finite value, in this case it is used to avoid a possible division by 0.

November 9, 2009, 19:54	what does the function min() do???	#1
sven Member Sven Winkler Join Date: May 2009 Posts: 70 Rep Power: 16	Somewhere in the source Code of a turbulence model I found something which I dont understand. Unfortunately the understanding of this line is crucial to what I am doing. The line I am talking about is Code: P[faceCelli] = min(G[faceCelli]/(0.5mag(tr(P[faceCelli])) + SMALL), 1.0); What I dont understand are the following things: what is SMALL? A variable a function?? what does the function min do? Does it select eitherG[faceCelli]/(0.5*mag(tr(P[faceCelli])) + SMALL) or 1.0, depending on which value is the smaller one If I do some more source Code searching, I find Code: inline retType min(const type1 s1, const type2 s2) \ { \ return (s1 < s2)? s1: s2; \ } Can someone understand this? Thank you very much!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Compile problem	ivanyao	OpenFOAM Running, Solving & CFD	1	October 12, 2012 09:31
[blockMesh] BlockMesh FOAM warning	gaottino	OpenFOAM Meshing & Mesh Conversion	7	July 19, 2010 14:11
Error with Wmake	skabilan	OpenFOAM Installation	3	July 28, 2009 00:35
On the damBreak4phaseFine cases	paean	OpenFOAM Running, Solving & CFD	0	November 14, 2008 21:14
[blockMesh] Axisymmetrical mesh	Rasmus Gjesing (Gjesing)	OpenFOAM Meshing & Mesh Conversion	10	April 2, 2007 14:00

November 9, 2009, 21:41		#2
Simon Lapointe Member Simon Lapointe Join Date: May 2009 Location: Québec, Qc, Canada Posts: 33 Rep Power: 16	Hi, min(a,b) returns the smallest value between a and b. SMALL stands for a small finite value, in this case it is used to avoid a possible division by 0.