1 #ifdef PETSC_RCS_HEADER 2 static char vcid[] = "$Id: snesj2.c,v 1.13 1997/11/28 16:21:38 bsmith 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 Input Parameters: 15 . snes - nonlinear solver object 16 . x1 - location at which to evaluate Jacobian 17 . ctx - coloring context, where 18 $ ctx must have type MatFDColoring, 19 $ as created via MatFDColoringCreate() 20 21 Output Parameters: 22 . J - Jacobian matrix (not altered in this routine) 23 . B - newly computed Jacobian matrix to use with preconditioner (generally the same as J) 24 . flag - flag indicating whether the matrix sparsity structure has changed 25 26 Collective on SNES 27 28 Options Database Keys: 29 $ -mat_fd_coloring_freq <freq> 30 31 .keywords: SNES, finite differences, Jacobian, coloring, sparse 32 33 .seealso: SNESSetJacobian(), SNESTestJacobian(), SNESDefaultComputeJacobian() 34 @*/ 35 int SNESDefaultComputeJacobianWithColoring(SNES snes,Vec x1,Mat *J,Mat *B,MatStructure *flag,void *ctx) 36 { 37 MatFDColoring color = (MatFDColoring) ctx; 38 int ierr,freq,it; 39 40 PetscFunctionBegin; 41 ierr = MatFDColoringGetFrequency(color,&freq);CHKERRQ(ierr); 42 ierr = SNESGetIterationNumber(snes,&it); CHKERRQ(ierr); 43 44 if ((freq > 1) && ((it % freq) != 1)) { 45 PLogInfo(color,"SNESDefaultComputeJacobianWithColoring:Skipping Jacobian, it %d, freq %d\n",it,freq); 46 *flag = SAME_PRECONDITIONER; 47 PetscFunctionReturn(0); 48 } else { 49 PLogInfo(color,"SNESDefaultComputeJacobianWithColoring:Computing Jacobian, it %d, freq %d\n",it,freq); 50 *flag = SAME_NONZERO_PATTERN; 51 } 52 53 54 PLogEventBegin(SNES_FunctionEval,snes,x1,0,0); 55 PetscStackPush("SNES user function"); 56 ierr = MatFDColoringApply(*B,color,x1,flag,snes); CHKERRQ(ierr); 57 PetscStackPop; 58 snes->nfuncs++; 59 PLogEventEnd(SNES_FunctionEval,snes,x1,0,0); 60 PetscFunctionReturn(0); 61 } 62 63 64 65