> On Dec 20, 2016, at 10:50 AM, Ji Zhang <[email protected]> wrote: > > Dear all, > > I'm a petsc user. Currently, the system I face is so huge that is out of > memory. I want to perform fast multipole method using petsc. Is it possible > for me to tell the solver the result of matrix-vector product, which is gmres > need indeed, instead of generate the whole matrix directly?
Absolutely. http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatCreateShell.html http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatShellSetOperation.html follow the examples links for some simple examples. Barry > For example, give a function headle to the solver. > > Thanks. > > 此致 > 敬礼 > 张骥（博士研究生） > 北京计算科学研究中心 > 北京市海淀区西北旺东路10号院东区9号楼 （100193） > > Best, > Regards, > Zhang Ji, PhD student > Beijing Computational Science Research Center > Zhongguancun Software Park II, No. 10 Dongbeiwang West Road, Haidian > District, Beijing 100193, China
