This was added in 3.8 to check the common case when people incorrectly sets shift-and-invert with EPS_SMALLEST_MAGNITUDE. To compute smallest eigenvalues with shift-and-invert the correct way is to set target=0 and which=EPS_TARGET_MAGNITUDE. See for instance http://slepc.upv.es/documentation/current/src/eps/examples/tutorials/ex13.c.html
Jose > El 21 oct 2017, a las 1:51, Matthew Knepley <[email protected]> escribió: > > On Fri, Oct 20, 2017 at 7:43 PM, Kong, Fande <[email protected]> wrote: > Hi All, > > I am trying to solve a generalized eigenvalue problem (using SLEPc) with > "-eps_type krylovschur -st_type sinvert". I got an error message: "Must > select a target sorting criterion if using shift-and-invert". > > Not sure how to proceed. I do not quite understand this sentence. > > You need to know how to choose the shift. So for instance you want the > smallest eigenvalues, or the closest to zero, etc. > I don't know the options, but they are in the manual. > > Matt > > > Fande, > > > > -- > 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/
