Mat indices always start with 0 in global indexing used by MatSetValues, MatSetValuesBlocked
With “local orderings” on can chose to use whatever indexing makes sense for your local ordering, this is used with MatSetValuesLocal(), MatSetValuesBlockedLocal(). Barry On Sep 21, 2014, at 10:35 AM, Feng Shi <[email protected]> wrote: > Hi all, > > When setting the Mat indices, like the example: > src/ts/examples/tutorials/ex10, I noticed that on line > > 508: col[0] = i-1; > 509: col[1] = i; > 510: col[2] = i+1<info.mx ? i+1 : -1; > 511: > MatSetValuesBlocked<http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatSetValuesBlocked.html#MatSetValuesBlocked>(B,1,&i,3,col,&K[0][0],INSERT_VALUES<http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Sys/INSERT_VALUES.html#INSERT_VALUES>); > > How about the case that when i=0, then col[0]=-1 and i=info.mx then col[2]=-1? > My question is, is the Mat default indices starting from -1? > > Thank you in advance! > > Best regards, > > Feng
