On Sep 1, 2013, at 8:37 AM, Tabrez Ali <[email protected]> wrote:
> I am using solid elements and here's what I get for the smallest problem with > -pc_type svd -pc_svd_monitor > > SVD: condition number 4.184203727999e+13, 0 of 2187 singular values are > (nearly) zero > SVD: smallest singular values: 9.975131304660e-01 9.979349868120e-01 > 9.986761984005e-01 9.993267254639e-01 9.996135846381e-01 > SVD: largest singular values : 3.933977100529e+13 3.933977100529e+13 > 4.162059658259e+13 4.162059658259e+13 4.173798159224e+13 > This is a very large condition number for a "vanilla 3D linear elasticity problem" [there are no rotations]. The 5 lowest values are very similar … are you sure you have sufficient BCs? > Tabrez > > On 08/31/2013 03:06 PM, Umut Tabak wrote: >> On 08/31/2013 06:25 PM, Tabrez Ali wrote: >>> Hello >>> >>> So I used PCSetCoordinates and now GAMG seems to work really well in that >>> the number of iterations are relatively constant. Here are the number of >>> iterations on 4 cores >>> >>> DOF ASM GAMG >>> 2187 15 22 >>> 14739 26 22 >>> 107811 51 29 >> >> Hi, >> >> Just curious, what is the approximate condition number of this matrix, is >> that modelled with domain elements like solids or thin elements like shells? >> >> Best, >> U. >
