Re: [deal.II] how to get the inverse of a sparse matrix?

Dear FU, Yes, I think that the LinearOperator class and family of helper functions can help you here. This is because you never use the matrix “A” in isolation

Re: [deal.II] Re: Trouble building from source on MacOS

I have been building deal.II on mac for many years and never found the need to set DYLD_LIBRARY_PATH. My preferred way to install deal.II on mac/linux is Install gcc using homebrew (to get gfortran) Install spack and deal.II dependencies http://cpraveen.github.io/comp/spack.html

Re: [deal.II] Outputting auxiliary cell-level data along with solution data

You can use this https://dealii.org/developer/doxygen/deal.II/structGridOutFlags_1_1Vtu.html https://dealii.org/developer/doxygen/deal.II/structDataOutBase_1_1VtkFlags.html

Re: [deal.II] how to get the inverse of a sparse matrix?

Hi， I want to solve AT+BFT^4=C (1), A, B, F are sparse matrix, T, T^4 are the solution vector. By Newton method, we need to (1) derivation. So I want to know how to get A. Or what do you think of solving this equation? best， FU 在 2018年11月15日星期四 UTC+8下午10:45:24，Jean-Paul Pelteret写道： > >

[deal.II] Outputting auxiliary cell-level data along with solution data

I have a model where I'm using the boundary_id to specify boundary regions where certain boundary conditions apply, and I'd like to add the boundary_id numbers to the output, so I can see them spatially in Paraview along with my solution output. I'm currently trying to use a DataOutFaces objec

Re: [deal.II] Re: Trouble building from source on MacOS

It turns out my DYLD_LIBRARY_PATH variable was set to search in the macports directory tree, and, as I understand it, it overrides the paths for the shared libraries I specified through cmake. I was having a heck of a time figuring out why my code was having runtime problems with libraries from

Re: [deal.II] how to get the inverse of a sparse matrix?

Hi, In general there is, to the best of my knowledge, no easy answer to your question. Can you explain what you intend to do with the matrix “A"? That would help a great deal, as there may still be some functionality in the library to help you. If you intend to perform some operations with “A”

Re: [deal.II] how to get the inverse of a sparse matrix?

Thank you very much for your reply. I probably understand the methods you mentioned, but there is no multiplication vector behind the sparse matrix of the solution I asked for. A=M- (N^T) (M^-1) N, This is the construction equation of the original sparse matrix. A is the sparse matrix that I w

Re: [deal.II] how to get the inverse of a sparse matrix?

Thank you very much for your reply. I probably understand the methods you mentioned, but there is no multiplication vector behind the sparse matrix of the solution I asked for. A=M- (N^T) (M^-1) N, This is the construction equation of the original sparse matrix. A is the sparse matrix that I w

Re: [deal.II] how to get the inverse of a sparse matrix?

非常感谢您的回复。 我可能理解你提到的方法，但是在我要求的解决方案的稀疏矩阵后面没有乘法向量。 A = M-（N ^ T）（M ^ -1）N， 这是原始稀疏矩阵的构造方程。 A是我想在最后获得的稀疏矩阵，其中N和M是稀疏矩阵。 你还能做些什么来解决这个问题？ 谢谢 FU 在 2018年11月14日星期三 UTC+8下午2:32:03，Jean-Paul Pelteret写道： > > 嗨， > > 要计算稀疏矩阵逆M ^ { - 1}，您必须使用直接求解器，例如 SparseDirectUMFPACK >