191627157SBarry Smith 2b45d2f2cSJed Brown #include <petsc-private/snesimpl.h> /*I "petscsnes.h" I*/ 391627157SBarry Smith 44a2ae208SSatish Balay #undef __FUNCT__ 54a2ae208SSatish Balay #define __FUNCT__ "SNESDefaultComputeJacobianColor" 691627157SBarry Smith /*@C 72d0c0e3bSBarry Smith SNESDefaultComputeJacobianColor - Computes the Jacobian using 8b4fc646aSLois Curfman McInnes finite differences and coloring to exploit matrix sparsity. 991627157SBarry Smith 10fee21e36SBarry Smith Collective on SNES 11fee21e36SBarry Smith 12c7afd0dbSLois Curfman McInnes Input Parameters: 13c7afd0dbSLois Curfman McInnes + snes - nonlinear solver object 14c7afd0dbSLois Curfman McInnes . x1 - location at which to evaluate Jacobian 15c7afd0dbSLois Curfman McInnes - ctx - coloring context, where ctx must have type MatFDColoring, 16c7afd0dbSLois Curfman McInnes as created via MatFDColoringCreate() 17c7afd0dbSLois Curfman McInnes 18c7afd0dbSLois Curfman McInnes Output Parameters: 19c7afd0dbSLois Curfman McInnes + J - Jacobian matrix (not altered in this routine) 20c7afd0dbSLois Curfman McInnes . B - newly computed Jacobian matrix to use with preconditioner (generally the same as J) 21c7afd0dbSLois Curfman McInnes - flag - flag indicating whether the matrix sparsity structure has changed 22c7afd0dbSLois Curfman McInnes 2336851e7fSLois Curfman McInnes Level: intermediate 2436851e7fSLois Curfman McInnes 25b4fc646aSLois Curfman McInnes .keywords: SNES, finite differences, Jacobian, coloring, sparse 2691627157SBarry Smith 27b4fc646aSLois Curfman McInnes .seealso: SNESSetJacobian(), SNESTestJacobian(), SNESDefaultComputeJacobian() 28ab637aeaSJed Brown MatFDColoringCreate(), MatFDColoringSetFunction() 29cb5b572fSBarry Smith 3091627157SBarry Smith @*/ 3195d750ceSBarry Smith 327087cfbeSBarry Smith PetscErrorCode SNESDefaultComputeJacobianColor(SNES snes,Vec x1,Mat *J,Mat *B,MatStructure *flag,void *ctx) 3391627157SBarry Smith { 34*4e269d77SPeter Brune MatFDColoring color = PETSC_NULL; //(MatFDColoring)ctx; 35dfbe8321SBarry Smith PetscErrorCode ierr; 36*4e269d77SPeter Brune DM dm; 37*4e269d77SPeter Brune PetscErrorCode (*func)(SNES,Vec,Vec,void*); 38*4e269d77SPeter Brune Vec F; 39*4e269d77SPeter Brune void *funcctx; 40*4e269d77SPeter Brune ISColoring iscoloring; 41dff777c9SBarry Smith 423a40ed3dSBarry Smith PetscFunctionBegin; 43*4e269d77SPeter Brune /* PetscValidHeaderSpecific(color,MAT_FDCOLORING_CLASSID,6);*/ 44*4e269d77SPeter Brune ierr = PetscObjectQuery((PetscObject)*B,"SNESMatFDColoring",(PetscObject *)&color);CHKERRQ(ierr); 4592abec31SBarry Smith *flag = SAME_NONZERO_PATTERN; 46*4e269d77SPeter Brune ierr = SNESGetFunction(snes,&F,&func,&funcctx); 47*4e269d77SPeter Brune if (!color) { 48*4e269d77SPeter Brune ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr); 49*4e269d77SPeter Brune /* temporarily reset the context by creating a new one*/ 50*4e269d77SPeter Brune ierr = DMCreateColoring(dm,IS_COLORING_GLOBAL,MATAIJ,&iscoloring);CHKERRQ(ierr); 51*4e269d77SPeter Brune ierr = MatFDColoringCreate(*B,iscoloring,&color);CHKERRQ(ierr); 52*4e269d77SPeter Brune ierr = ISColoringDestroy(&iscoloring);CHKERRQ(ierr); 53*4e269d77SPeter Brune ierr = MatFDColoringSetFunction(color,(PetscErrorCode (*)(void))func,funcctx);CHKERRQ(ierr); 54*4e269d77SPeter Brune ierr = MatFDColoringSetFromOptions(color);CHKERRQ(ierr); 55*4e269d77SPeter Brune ierr = PetscObjectCompose((PetscObject)*B,"SNESMatFDColoring",(PetscObject)color);CHKERRQ(ierr); 564a9d489dSBarry Smith } 57*4e269d77SPeter Brune ierr = MatFDColoringSetF(color,PETSC_NULL);CHKERRQ(ierr); 58005c665bSBarry Smith ierr = MatFDColoringApply(*B,color,x1,flag,snes);CHKERRQ(ierr); 5932dfb669SBarry Smith if (*J != *B) { 60194405b3SBarry Smith ierr = MatAssemblyBegin(*J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 61194405b3SBarry Smith ierr = MatAssemblyEnd(*J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 62194405b3SBarry Smith } 633a40ed3dSBarry Smith PetscFunctionReturn(0); 6491627157SBarry Smith } 65