Dear Petsc developer: Hi, Thank you very much for your previous reply, recently I encountered some problems in the implementation of the program.
1. Previously I used DMDA to create distributed variables (Variables are different in each grids). Now I want to add a single variable (independent of the grid). How do I add it? How do I write programs with distributed variables and single variables exist at the same time? I've created three "Field" variables before, and I'd like to add a single variable. How should I describe it in the program? The codes are as below. ierr=DMDACreate2d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,10,10,PETSC_DECIDE,PETSC_DECIDE,3,1,0,0,&da);CHKERRQ(ierr); ierr = DMSetFromOptions(da);CHKERRQ(ierr); ierr = DMSetUp(da);CHKERRQ(ierr); ierr = SNESSetDM(snes,(DM)da);CHKERRQ(ierr); ierr = DMDASetFieldName(da,0,"Pressure");CHKERRQ(ierr); ierr = DMDASetFieldName(da,1,"Y-Velocity");CHKERRQ(ierr); ierr = DMDASetFieldName(da,2,"Fluid_temperature");CHKERRQ(ierr); ierr = DMCreateGlobalVector(da,&x);CHKERRQ(ierr); 2. At present, I am solving nonlinear equations. Now I need to do one-step nonlinear calculation first, and then treat the results as coefficients for the subsequent nonlinear calculation. Now I used to use SNESSolve() directly to solve the problem. How can we calculate step by step and process the result before entering the next nonlinear step? Since I'm a beginner in PETSc, I would be grateful if there were any examples. I'm looking forward to your reply~ Thanks, Yingjie
