# Triangulation condition for timeVaryingMappedFixedValue

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 August 27, 2009, 09:57 Triangulation condition for timeVaryingMappedFixedValue #1 Senior Member     Sebastian Gatzka Join Date: Mar 2009 Location: Frankfurt, Germany Posts: 729 Rep Power: 12 Hello World. I'm currently trying to understand the check for a correct local coordinate system with the use of timeVaryingMappedFixedValue boundary condition. For simplicity I will post the relevant part of the code. The complete code is here: http://foam.sourceforge.net/doc/Doxy...8C_source.html Code: ``` const point& p0 = samplePoints[0]; // Find point separate from p0 vector e1; label index1 = -1; for (label i = 1; i < samplePoints.size(); i++) { e1 = samplePoints[i] - p0; scalar magE1 = mag(e1); if (magE1 > SMALL) { e1 /= magE1; index1 = i; break; } } // Find point that makes angle with n1 label index2 = -1; vector e2; vector n; for (label i = index1+1; i < samplePoints.size(); i++) { e2 = samplePoints[i] - p0; scalar magE2 = mag(e2); if (magE2 > SMALL) { e2 /= magE2; n = e1^e2; scalar magN = mag(n); if (magN > SMALL) { index2 = i; n /= magN; break; } } }``` Now my questions are: the condition for a "pass through" seems to be magE1 > SMALL and magN > SMALL ? Now I haven't found any definition of what SMALL may be? What is it? Where is it defined? What kind of operation is e1 /= magE1 ? What is the break command doing? What is n = e1^e2 doing? This is not a power-operation, right?! __________________ Schrödingers wife: "What did you do to the cat? It's half dead!"