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April 19, 2010, 12:29 |
if-loop, volScalarField comparison
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#1 |
New Member
Volker Tritschler
Join Date: Jan 2010
Posts: 20
Rep Power: 16 |
Hi all,
I have a problem with a task, which seemed to be straight-forward to solve at first. I need to program an if-loop in order to compare one volScalarField (P1) to another one (P2), and for each grid point, where P1 >= P2, a certain value (d) has to be written to another volScalarField (N) at exactly the same grid point. I wrote something like: (a, b, c, d are placeholder for arbitrary volScalarFields) Code:
volScalarField P1 = a; volScalarField P2 = b; volScalarField N = c; if (P1 >= P2) { N = d; } else { N = -d; } It's more that it just compares just one (the first?!) point of P1 with P2. Right now, I don't have any idea how to get rid of that problem, though it seems to be a very silly one. Thanks for any idea. greets, volker |
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April 22, 2010, 01:30 |
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#2 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
Hi,
you have to loop over your cells to compare information in each point: Code:
forAll(P1, cellI) { if (P1[cellI] > P2[cellI]) { N[cellI] = ... } else { ... } }
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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April 22, 2010, 04:42 |
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#3 |
New Member
Volker Tritschler
Join Date: Jan 2010
Posts: 20
Rep Power: 16 |
hi alberto,
so many thanks for your help!!! It worked great. I wasn't aware of that class 'cell'. Do you know if there is a way to loop over the boundary patches as well? best volker |
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April 22, 2010, 11:11 |
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#4 | ||
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
Quote:
Quote:
Code:
forAll(p.boundaryField(), patchi) { // Check if it's zeroGradient (optional, depending on your case) if (isA<zeroGradientFvPatchScalarField>(p.boundaryField()[patchi])) { otherFieldA.boundaryField()[patchi] = 0.0; otherFieldB.boundaryField()[patchi] = 0.0; } }
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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April 23, 2010, 14:02 |
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#5 |
New Member
Volker Tritschler
Join Date: Jan 2010
Posts: 20
Rep Power: 16 |
perfect, big thanks to you!
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April 23, 2010, 15:18 |
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#6 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
You're welcome
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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February 27, 2020, 16:13 |
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#7 |
New Member
tooran
Join Date: Nov 2016
Posts: 23
Rep Power: 10 |
I am tyring to change a viscoisty model. I need to campare strain rate with a constant parameter (gama)
if strainrate is greater than the gama then do.... so I write : ************************************************** ******************* Foam::viscosityModels::MyHerschelBulkley::calcNu() const { dimensionedScalar tone("tone", dimTime, 1.0); dimensionedScalar rtone("rtone", dimless/dimTime, 1.0); tmp<volScalarField> sr(strainRate()); forAll(calcNu.internalField(), cellI) { if (sr[cellI]< gama_.value()) { ...... It shows me the error: error : calcNu’ does not have class type forAll(calcNu.internalField(), cellI) could you please help me? MyHerschelBulkley.C MyHerschelBulkley.H |
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March 6, 2020, 21:03 |
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#8 |
New Member
tooran
Join Date: Nov 2016
Posts: 23
Rep Power: 10 |
Can any one help me?
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