OpenFOAM周期边界生成不成功，cyclic的问题

youmengtian

另，建议改小matchToTolerance。相对于你的网格尺寸，这个值明显偏大。

random_ran

嗨 youmengtian：

非常感谢阅读我的这个瞎折腾! 当时是想看看 OF 到底能跑多大的网格，所以才有了这些。

由于这是 cfd-china ，默认大家都用中文，所以我有点担心会不会影响到别人。但是，这种边看代码，边写文档的东西，我目前只能在在 emacs 中高效地完成，所以就只能用英文来交流。如果冒犯到你，请不要继续往下读。

I am using OF-dev version (don't know exactly the date I downloaded
it).

The main classes are found in the flowing path:

~/OpenFOAM-dev/src/dynamicMesh/polyTopoChange/polyTopoChange/modifyObject/

This for loop:

//Line 707
//~/OpenFOAM-dev/applications/utilities/mesh/manipulation/createPatch/createPatch.C

void changePatchID
(
  const polyMesh& mesh,
  const label faceID,
  const label patchID,
  polyTopoChange& meshMod
)

is the point that I feel something might wrong.

I don't know exactly what polyModifyFace is a function or a
class. I double checked the defination of polyModifyFace:

//Line 82
//~OpenFOAM-dev/src/dynamicMesh/polyTopoChange/polyTopoChange/modifyObject/polyModifyPoint.H
meshMod.setAction
  (
      polyModifyFace
      (
	  mesh.faces()[faceID],               // face
	  faceID,                             // face ID
	  mesh.faceOwner()[faceID],           // owner
	  -1,                                 // neighbour
	  false,                              // flip flux
	  patchID,                            // patch ID
	  false,                              // remove from zone
	  zoneID,                             // zone ID
	  zoneFlip                            // zone flip
      )
  );

I think polyModifyFace really looks like a function definition in
c++, but I might wrong.

Another thing that I feel strange is that the implementation of the
following classes are missing.

3.5k 12-14 23:52 polyModifyCell.H
7.5k 12-14 23:52 polyModifyFace.H
4.2k 12-14 23:52 polyModifyPoint.H

Is that becasue those classes are too easy?

I furthe study the class (~/OpenFOAM-dev/src/dynamicMesh/polyTopoChange/polyTopoChange/modifyObject/polyModifyFace.H):

//- Construct and return a clone
virtual autoPtr<topoAction> clone() const
{
    return autoPtr<topoAction>(new polyModifyFace(*this));
}

Is this clone() function mess up all the things? If so, what's the
limited of it? How big (size of the mesh) the OF can handle?

I agree with you. This mesh is converted from \*.msh file without any
issue. convertMesh seems have a much large memory requirement. I am
not sure exactly the order of it.

What I want to do, is to run some small test to investigate the
memory usage of convertMesh and creatPatch.

Finally, why make it (matchToTolerance) smaller? Do you have any
reference to this point? I might (can remember exactly) just use
some default number here.

wwzhao

@random_ran 我猜可能是 int 类型长度限制的原因。你看一下 echo $WM_LABEL_SIZE ，默认是 32，如果要用超大网格，需要在编译前将 WM_LABEL_SIZE 设为 64。

youmengtian

@random_ran 您说的太客气了，虽然咱们这儿叫CFD中文网但是也没说不让使用英文。你之前的阅读逻辑是没有什么错误的，但是我不知道你怎么读到polyModifyPoint.H这个头文件去，因为我觉得貌似跟这个头文件没有关系。但是我感觉你对错误的基本定位应该是准确的，应该就出现在polyModifyFace.H第190行开辟新的智能指针出错了

polyModifyFace.H      188
virtual autoPtr<topoAction> clone() const
{
    return autoPtr<topoAction>(new polyModifyFace(*this));
}

random_ran

因为我几次遇到过在网络上由于这种潜在规则的问题的不明了导致的一些不必要的麻烦，所以谨慎点应该的。看来之后的交流会更加便捷：）

@youmengtian

The reason why I checked polyModifyFace was that I wanted to study
the piece of code in:

//Line 82
//~OpenFOAM-dev/src/dynamicMesh/polyTopoChange/polyTopoChange/modifyObject/polyModifyPoint.H [wrong!]
///OpenFOAM-dev/applications/utilities/mesh/manipulation/createPatch/createPatch.C [correct]
meshMod.setAction
  (
      polyModifyFace
      (
	  mesh.faces()[faceID],               // face
	  faceID,                             // face ID
	  mesh.faceOwner()[faceID],           // owner
	  -1,                                 // neighbour
	  false,                              // flip flux
	  patchID,                            // patch ID
	  false,                              // remove from zone
	  zoneID,                             // zone ID
	  zoneFlip                            // zone flip
      )
  );

I don't know the reason why it crash, that's why I am asking.

return autoPtr<topoAction>(new polyModifyFace(*this));

Do you know how this function could trigger the following exception:

terminate called after throwing an instance of 'std::bad_array_new_length'
what():  std::bad_array_new_length

I don't know.

@wwzhao

thanks for helping. This test case was built Jul 06 2018,
so I am not sure the exactly envirmental varibles that I was playing with.

I've double checked the:

echo $WM_LABEL_SIZE
32

It looks like a right direction to further study this stuff. But, it
needs more time, since I need to rebuid OF. Which Version would you
like to suggest me to run? dev or v4.1?

Also, if the default

$WM_LABEL_SIZE</sub> is indeed 32

what is its theoretical upper bond, i.e. running pisoFoam (motobike tutorial?).

Can I change to any number (2^{5,6,7,8})?

wwzhao

@random_ran OpenFOAM中用label表示point、face和cell的size，默认情况下label为int32类型（WM_LABEL_SIZE=32）。抛出异常的原因很可能是由于对face size的计算超过了int32类型的最大限制，导致变为负数。若将label用int64类型表示（WM_LABEL_SIZE=64）则应该可以避免这个问题。不过所有label类型的变量占用内存是原来的两倍。

wwzhao

关于OpenFOAM版本，没必要追求最新，够自己用就行。

wwzhao

理论上限跟WM_LABEL_SIZE有关，若任何一个label数组长度超过2^(N-1)-1（对int32是2^31-1，对int64是2^63-1），则会抛出异常。

random_ran

好的，我再仔细研究研究这个 LABEL_SIZE 的东西。有新的进展我再贴在这里。

(话说你的博客好赞啊！超喜欢这种风格。不知道是否接受 OF 热心读者的问题呢？直接留言在 Disqus 好还是在这里发帖，博主会看见呢？)

wwzhao

@random_ran

哈哈，多谢捧场。博客是用markdown写的，记录了一些自己对OpenFOAM的理解，初学者阅读可能比较吃力

有问题欢迎交流，Disqus跟论坛均可，我都能看到 :w: