View source for OpenFOAM guide/Programmer's Guide Errata

Community created ''Errata'' for the OpenFOAM ''Programmer's Guide'':
* Online version: [https://sourceforge.net/projects/openfoamplus/files/v1606+/ProgrammersGuide-v1606.pdf OpenFOAM ''Programmer's Guide'' at SF.net]
* The local version in your installation can be found by running one of the respective commands:
** On OpenFOAM 3.0 and older, as well as foam-extend and all OpenFOAM+ versions: <bash>echo $WM_PROJECT_DIR/doc/Guides-a4/ProgrammersGuide.pdf</bash>
** As of OpenFOAM 4, there is no Programmer's Guide. This is now maintained by the [http://openfoam.com OpenFOAM+ project].

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'''Notes to contributors:''' Please include the chapter number of the printed version to avoid confusion (the Wiki might give different chapter numbers) 
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= Chapter 1: Tensor mathematics =


== Section 1.2: Tensors ==

As reported in the [http://bugs.openfoam.org/view.php?id=1068 bug report #1068], there are a couple of references to ''OpenFOAM 1.x'', which is likely an old reference to the original FOAM 2.x version. Feel free to compare to the old documentation at Nabla: the old Programmer's Guide, section [http://www.foamcfd.org/Nabla/guides/ProgrammersGuidese2.html#x5-40001.2 1.2 Tensors].

Either way, feel free to disregard the ''1.x'' reference, since its objective is reflect that tensors as a mathematical entity, are only partially implemented in OpenFOAM.


== Section 1.4: OpenFOAM tensor classes ==


=== Subsection 1.4.1: Algebraic tensor operations in OpenFOAM ===
{{versionInfo}}{{Version1.6}}{{Version1.7}}{{Version2.0}}{{Version2.1}}{{Version2.2}}

In ''Table 1.2: Algebraic tensor operations in OpenFOAM'', the following entries need fixing:
{| border="1" cellpadding="2"
! Operation !! Description in OpenFOAM<br>''(wrong)'' !! Description in OpenFOAM<br>''(correct)''
|-
| Component maximum || max(a) || cmptMax(a)
|-
| Component minimum || min(a) || cmptMin(a)
|-
| Scale || scale(a,b) || cmptMultiply(a,b)
|}

= Chapter 2: Discretisation procedures =

== Section 2.1: Differential operators ==

=== Subsection 2.1.2: Divergence ===
{{versionInfo}}{{Version1.5}}{{Version1.6}}{{Version1.7}}{{Version2.0}}{{Version2.1}}

('''Note''': Already fixed in {{Version2.2}})

The documented divergence operator for tensors is incorrect:

<math>
\nabla \bullet T = \partial_i T_{ij}=\left(
\begin{matrix}
\frac{\partial T_{11}}{\partial x_1}     + \frac{\partial T_{12}}{\partial x_1}     + \frac{\partial T_{13}}{\partial x_1}\\
\frac{\partial T_{21}}{\partial x_2}     + \frac{\partial T_{22}}{\partial x_2}     + \frac{\partial T_{23}}{\partial x_2}\\
\frac{\partial T_{31}}{\partial x_3}     + \frac{\partial T_{32}}{\partial x_3}     + \frac{\partial T_{33}}{\partial x_3}    
\end{matrix}
\right)
</math>

It should be:

<math>
\nabla \bullet T =
\left(
\begin{matrix}
\frac{\partial }{\partial x_1}, & \frac{\partial }{\partial x_2}, & \frac{\partial}{\partial x_3}
\end{matrix}
\right)
\bullet
\left(
\begin{matrix}
T_{11} &    T_{12} &    T_{13}    \\
T_{21} &    T_{22} &    T_{33}    \\
T_{31} &    T_{32} &    T_{33}    \\
\end{matrix}
\right)
=\partial_j T_{ji}=\left(
\begin{matrix}
\frac{\partial T_{11}}{\partial x_1}     + \frac{\partial T_{21}}{\partial x_2}     + \frac{\partial T_{31}}{\partial x_3}\\
\frac{\partial T_{12}}{\partial x_1}     + \frac{\partial T_{22}}{\partial x_2}     + \frac{\partial T_{33}}{\partial x_3}\\
\frac{\partial T_{13}}{\partial x_1}     + \frac{\partial T_{32}}{\partial x_2}     + \frac{\partial T_{33}}{\partial x_3}    
\end{matrix}
\right)
</math>


== Section 2.4: Equation discretisation ==


=== Subsection 2.4.6: Gradient ===

{{versionInfo}}{{Version1.6}}{{Version1.7}}{{Version2.0}}{{Version2.1}}{{Version2.2}}

* All references to '''timeScheme''' should be either ''gradSchemes'' or ''snGradSchemes'' [http://www.cfd-online.com/Forums/openfoam-bugs/82225-programmers-guide-p-40-a.html].
* The indication of '''[Check**]''' implies that this subsection needs to be revised.


=== Subsection 2.6.1: Physical boundary conditions ===

{{versionInfo}}{{Version1.6}}{{Version1.7}}{{Version2.0}}{{Version2.1}}{{Version2.2}}

* The indication of '''[Check**]''' implies that this subsection needs to be revised.



= Chapter 3: Examples of the use of OpenFOAM =


= Chapter 4: Programming techniques =


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= Known forum threads on this topic =
This is a unordered list of links to threads about typos and errors in the ''Programmer's Guide'' that have been found by the community:

* [http://www.cfd-online.com/Forums/openfoam-bugs/104867-bug-programmers-guide-divergence-tensor-field.html Bug in the programmer's guide: divergence of a tensor field]
** Documented in [[#Subsection 2.1.2: Divergence|Subsection 2.1.2: Divergence]], but keep in mind that this has already been fixed.
* [http://www.cfd-online.com/Forums/openfoam-bugs/82225-programmers-guide-p-40-a.html In Programmer's Guide p. 40]
** The issues in post #1 are at [[#Subsection 2.4.6: Gradient|Subsection 2.4.6: Gradient]] and [[#Subsection 2.6.1: Physical boundary conditions|Subsection 2.6.1: Physical boundary conditions]]
* [http://www.cfd-online.com/Forums/openfoam-bugs/73361-programmers-guide-bugs.html Programmers Guide Bugs]
** The issues indicated in post #1 are already here in the wiki in the subsection [[#Subsection 1.4.1 Algebraic tensor operations in OpenFOAM|Subsection 1.4.1 Algebraic tensor operations in OpenFOAM]].
* [http://www.cfd-online.com/Forums/openfoam-bugs/62533-error-documentation.html Error in documentation]
** Only affects {{version1.4.1}}

[[Category:OpenFOAM guide]]