You can run ~petsc/src/ksp/ksp/examples/tutorials/ex2.c with runtime option
petsc-3.1/src/ksp/ksp/examples/tutorials>./ex2 -ksp_type lsqr -ksp_monitor 0 KSP Residual norm 6.164414002969e+00 1 KSP Residual norm 3.193020760242e+00 ... 19 KSP Residual norm 5.405772406774e-04 Norm of error 0.000404485 iterations 19 option '-ksp_view' display the solver being used. Hong On Mon, Jan 17, 2011 at 2:15 AM, Gaurish Telang <gaurish108 at gmail.com> wrote: > Hi, > > I am new to PETSc and I wanted to solve some least squares problems with it. > On searching the net I found that KSPLSQR() and KSPCGNE() solve the least > squares system |Ax-b| > > But I don't really know how to use these functions to get my answer. This > manual page did not help: > http://www.mcs.anl.gov/petsc/petsc-2/snapshots/petsc-current/docs/manualpages/KSP/KSPLSQR.html > > Apparently no tutorial code uses these functions. > > If anyone could could give a small code snippet of how to use these > functions (assuming A and b are given) then it would be really helpful. > > Thanks, > > Gaurish >
