Please send your version of the example that computes the mean norm of the grid; I suspect we are talking apples and oranges
Barry > On Oct 1, 2018, at 7:51 PM, Weizhuo Wang <[email protected]> wrote: > > I also tried to divide the norm by m*n , which is the number of grids, the > trend of norm still increases. > > Thanks! > > Weizhuo > > Matthew Knepley <[email protected]> 于2018年10月1日周一 下午7:45写道： > On Mon, Oct 1, 2018 at 6:31 PM Weizhuo Wang <[email protected]> wrote: > Hi! > > I'm recently trying out the example code provided with the KSP solver > (ex12.c). I noticed that the mean norm of the grid increases as I use finer > meshes. For example, the mean norm is 5.72e-8 at m=10 n=10. However at m=100, > n=100, mean norm increases to 9.55e-6. This seems counter intuitive, since > most of the time error should decreases when using finer grid. Am I doing > this wrong? > > The norm is misleading in that it is the l_2 norm, meaning just the sqrt of > the sum of the squares of > the vector entries. It should be scaled by the volume element to approximate > a scale-independent > norm (like the L_2 norm). > > Thanks, > > Matt > > Thanks! > -- > Wang Weizhuo > > > -- > 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 > > https://www.cse.buffalo.edu/~knepley/ > > > -- > Wang Weizhuo
