[petsc-users] petsc malloc multidimensional array

[吕超]

Hi, Matthew:

     Thank you for your reply so fast! but I also have some questions:

    2d arrays I used is just intermediate variable, not for fields, and the fields is used Vector. In Finite element method, when I use element stiffness matrix to assemble global stiffness matrix, I always first compute the 2d element stiffness matrixs whose size is 512*512(inner points in element),so big for static arrays. So i want to use PetscMalloc to bulid 2d arrays to store element stiffness matrixs' values. And I don't know how to do, could do tell me?

     then use another 1d array to abstract the nonzero values from 2d arrays above-mentioned. could do you please tell me  some other methods much more convenient and faster?




-----原始邮件-----
发件人: "Matthew Knepley" <knepley at gmail.com>
发送时间: 2014年3月11日 星期二
收件人: "吕超" <luchao at mail.iggcas.ac.cn>
抄送: petsc-users <petsc-users at mcs.anl.gov>
主题: Re: [petsc-users] petsc malloc multidimensional array


On Tue, Mar 11, 2014 at 8:37 AM, 吕超 <luchao at mail.iggcas.ac.cn> wrote:


  Hi, recently,when I use PETSc to bulid 2d arrays such as PetscScalar A[512][512],B[512][512],C,D,E,F,..., program always has error of Segmentation Violation. So I want to use PetscMalloc to bulid 2d array, and I hope that I can also use these 2d array A[i][j] by subscripts as before. Could do please tell me how can I do? Thank you.

1) This is a C question, not a PETSc question


2) If you are using 2D arrays for fields, you should be using the DMDA, which has a section in the manual


  Thanks,


     Matt
 

LV CHAO

2014/3/11













--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener




-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20140311/97d14272/attachment-0001.html>