1 #ifdef PETSC_RCS_HEADER 2 static char vcid[] = "$Id: snesj2.c,v 1.15 1998/04/24 04:52:33 curfman Exp bsmith $"; 3 #endif 4 5 #include "src/mat/matimpl.h" /*I "mat.h" I*/ 6 #include "src/snes/snesimpl.h" /*I "snes.h" I*/ 7 8 #undef __FUNC__ 9 #define __FUNC__ "SNESDefaultComputeJacobianWithColoring" 10 /*@C 11 SNESDefaultComputeJacobianWithColoring - Computes the Jacobian using 12 finite differences and coloring to exploit matrix sparsity. 13 14 Collective on SNES 15 16 Input Parameters: 17 + snes - nonlinear solver object 18 . x1 - location at which to evaluate Jacobian 19 - ctx - coloring context, where ctx must have type MatFDColoring, 20 as created via MatFDColoringCreate() 21 22 Output Parameters: 23 + J - Jacobian matrix (not altered in this routine) 24 . B - newly computed Jacobian matrix to use with preconditioner (generally the same as J) 25 - flag - flag indicating whether the matrix sparsity structure has changed 26 27 Options Database Keys: 28 . -mat_fd_coloring_freq <freq> - Activates SNESDefaultComputeJacobianWithColoring() 29 30 .keywords: SNES, finite differences, Jacobian, coloring, sparse 31 32 .seealso: SNESSetJacobian(), SNESTestJacobian(), SNESDefaultComputeJacobian() 33 TSDefaultComputeJacobianWithColoring(), MatFDColoringCreate(), 34 MatFDColoringSetFunction() 35 36 @*/ 37 int SNESDefaultComputeJacobianWithColoring(SNES snes,Vec x1,Mat *J,Mat *B, 38 MatStructure *flag,void *ctx) 39 { 40 MatFDColoring color = (MatFDColoring) ctx; 41 int ierr,freq,it; 42 43 PetscFunctionBegin; 44 ierr = MatFDColoringGetFrequency(color,&freq);CHKERRQ(ierr); 45 ierr = SNESGetIterationNumber(snes,&it); CHKERRQ(ierr); 46 47 if ((freq > 1) && ((it % freq) != 1)) { 48 PLogInfo(color,"SNESDefaultComputeJacobianWithColoring:Skipping Jacobian, it %d, freq %d\n",it,freq); 49 *flag = SAME_PRECONDITIONER; 50 PetscFunctionReturn(0); 51 } else { 52 PLogInfo(color,"SNESDefaultComputeJacobianWithColoring:Computing Jacobian, it %d, freq %d\n",it,freq); 53 *flag = SAME_NONZERO_PATTERN; 54 } 55 56 57 PLogEventBegin(SNES_FunctionEval,snes,x1,0,0); 58 PetscStackPush("SNES user function"); 59 ierr = MatFDColoringApply(*B,color,x1,flag,snes); CHKERRQ(ierr); 60 PetscStackPop; 61 snes->nfuncs++; 62 PLogEventEnd(SNES_FunctionEval,snes,x1,0,0); 63 PetscFunctionReturn(0); 64 } 65 66 67 68