#ifdef PETSC_RCS_HEADER static char vcid[] = "$Id: ls.c,v 1.112 1998/06/02 14:45:25 balay Exp bsmith $"; #endif #include #include "src/snes/impls/ls/ls.h" #include "pinclude/pviewer.h" /* -------------------------------------------------------------------- This file implements a truncated Newton method with a line search, for solving a system of nonlinear equations, using the SLES, Vec, and Mat interfaces for linear solvers, vectors, and matrices, respectively. The following basic routines are required for each nonlinear solver: SNESCreate_XXX() - Creates a nonlinear solver context SNESSetFromOptions_XXX() - Sets runtime options SNESSolve_XXX() - Solves the nonlinear system SNESDestroy_XXX() - Destroys the nonlinear solver context The suffix "_XXX" denotes a particular implementation, in this case we use _EQ_LS (e.g., SNESCreate_EQ_LS, SNESSolve_EQ_LS) for solving systems of nonlinear equations (EQ) with a line search (LS) method. These routines are actually called via the common user interface routines SNESCreate(), SNESSetFromOptions(), SNESSolve(), and SNESDestroy(), so the application code interface remains identical for all nonlinear solvers. Another key routine is: SNESSetUp_XXX() - Prepares for the use of a nonlinear solver by setting data structures and options. The interface routine SNESSetUp() is not usually called directly by the user, but instead is called by SNESSolve() if necessary. Additional basic routines are: SNESPrintHelp_XXX() - Prints nonlinear solver runtime options SNESView_XXX() - Prints details of runtime options that have actually been used. These are called by application codes via the interface routines SNESPrintHelp() and SNESView(). The various types of solvers (preconditioners, Krylov subspace methods, nonlinear solvers, timesteppers) are all organized similarly, so the above description applies to these categories also. -------------------------------------------------------------------- */ /* SNESSolve_EQ_LS - Solves a nonlinear system with a truncated Newton method with a line search. Input Parameters: . snes - the SNES context Output Parameter: . outits - number of iterations until termination Application Interface Routine: SNESSolve() Notes: This implements essentially a truncated Newton method with a line search. By default a cubic backtracking line search is employed, as described in the text "Numerical Methods for Unconstrained Optimization and Nonlinear Equations" by Dennis and Schnabel. */ #undef __FUNC__ #define __FUNC__ "SNESSolve_EQ_LS" int SNESSolve_EQ_LS(SNES snes,int *outits) { SNES_LS *neP = (SNES_LS *) snes->data; int maxits, i, history_len, ierr, lits, lsfail; MatStructure flg = DIFFERENT_NONZERO_PATTERN; double fnorm, gnorm, xnorm, ynorm, *history; Vec Y, X, F, G, W, TMP; PetscFunctionBegin; history = snes->conv_hist; /* convergence history */ history_len = snes->conv_hist_size; /* convergence history length */ maxits = snes->max_its; /* maximum number of iterations */ X = snes->vec_sol; /* solution vector */ F = snes->vec_func; /* residual vector */ Y = snes->work[0]; /* work vectors */ G = snes->work[1]; W = snes->work[2]; snes->iter = 0; ierr = SNESComputeFunction(snes,X,F); CHKERRQ(ierr); /* F(X) */ ierr = VecNorm(F,NORM_2,&fnorm); CHKERRQ(ierr); /* fnorm <- ||F|| */ snes->norm = fnorm; if (history) history[0] = fnorm; SNESMonitor(snes,0,fnorm); if (fnorm < snes->atol) {*outits = 0; PetscFunctionReturn(0);} /* set parameter for default relative tolerance convergence test */ snes->ttol = fnorm*snes->rtol; for ( i=0; iiter = i+1; /* Solve J Y = F, where J is Jacobian matrix */ ierr = SNESComputeJacobian(snes,X,&snes->jacobian,&snes->jacobian_pre,&flg); CHKERRQ(ierr); ierr = SLESSetOperators(snes->sles,snes->jacobian,snes->jacobian_pre,flg); CHKERRQ(ierr); ierr = SLESSolve(snes->sles,F,Y,&lits); CHKERRQ(ierr); snes->linear_its += PetscAbsInt(lits); PLogInfo(snes,"SNESSolve_EQ_LS: iter=%d, linear solve iterations=%d\n",snes->iter,lits); /* Compute a (scaled) negative update in the line search routine: Y <- X - lambda*Y and evaluate G(Y) = function(Y)) */ ierr = VecCopy(Y,snes->vec_sol_update_always); CHKERRQ(ierr); ierr = (*neP->LineSearch)(snes,X,F,G,Y,W,fnorm,&ynorm,&gnorm,&lsfail); CHKERRQ(ierr); PLogInfo(snes,"SNESSolve_EQ_LS: fnorm=%g, gnorm=%g, ynorm=%g, lsfail=%d\n",fnorm,gnorm,ynorm,lsfail); if (lsfail) snes->nfailures++; TMP = F; F = G; snes->vec_func_always = F; G = TMP; TMP = X; X = Y; snes->vec_sol_always = X; Y = TMP; fnorm = gnorm; snes->norm = fnorm; if (history && history_len > i+1) history[i+1] = fnorm; SNESMonitor(snes,i+1,fnorm); /* Test for convergence */ if (snes->converged) { ierr = VecNorm(X,NORM_2,&xnorm); CHKERRQ(ierr); /* xnorm = || X || */ if ((*snes->converged)(snes,xnorm,ynorm,fnorm,snes->cnvP)) { break; } } } if (X != snes->vec_sol) { ierr = VecCopy(X,snes->vec_sol); CHKERRQ(ierr); snes->vec_sol_always = snes->vec_sol; snes->vec_func_always = snes->vec_func; } if (i == maxits) { PLogInfo(snes,"SNESSolve_EQ_LS: Maximum number of iterations has been reached: %d\n",maxits); i--; } if (history) snes->conv_act_size = (history_len < i+1) ? history_len : i+1; *outits = i+1; PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ /* SNESSetUp_EQ_LS - Sets up the internal data structures for the later use of the SNES_EQ_LS nonlinear solver. Input Parameter: . snes - the SNES context . x - the solution vector Application Interface Routine: SNESSetUp() Notes: For basic use of the SNES solvers the user need not explicitly call SNESSetUp(), since these actions will automatically occur during the call to SNESSolve(). */ #undef __FUNC__ #define __FUNC__ "SNESSetUp_EQ_LS" int SNESSetUp_EQ_LS(SNES snes) { int ierr; PetscFunctionBegin; snes->nwork = 4; ierr = VecDuplicateVecs(snes->vec_sol,snes->nwork,&snes->work);CHKERRQ(ierr); PLogObjectParents(snes,snes->nwork,snes->work); snes->vec_sol_update_always = snes->work[3]; PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ /* SNESDestroy_EQ_LS - Destroys the private SNES_LS context that was created with SNESCreate_EQ_LS(). Input Parameter: . snes - the SNES context Application Interface Routine: SNESSetDestroy() */ #undef __FUNC__ #define __FUNC__ "SNESDestroy_EQ_LS" int SNESDestroy_EQ_LS(SNES snes) { int ierr; PetscFunctionBegin; if (snes->nwork) { ierr = VecDestroyVecs(snes->work,snes->nwork); CHKERRQ(ierr); } PetscFree(snes->data); PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ #undef __FUNC__ #define __FUNC__ "SNESNoLineSearch" /*@C SNESNoLineSearch - This routine is not a line search at all; it simply uses the full Newton step. Thus, this routine is intended to serve as a template and is not recommended for general use. Collective on SNES and Vec Input Parameters: + snes - nonlinear context . x - current iterate . f - residual evaluated at x . y - search direction (contains new iterate on output) . w - work vector - fnorm - 2-norm of f Output Parameters: + g - residual evaluated at new iterate y . y - new iterate (contains search direction on input) . gnorm - 2-norm of g . ynorm - 2-norm of search length - flag - set to 0, indicating a successful line search Options Database Key: . -snes_eq_ls basic - Activates SNESNoLineSearch() .keywords: SNES, nonlinear, line search, cubic .seealso: SNESCubicLineSearch(), SNESQuadraticLineSearch(), SNESSetLineSearch() @*/ int SNESNoLineSearch(SNES snes, Vec x, Vec f, Vec g, Vec y, Vec w, double fnorm, double *ynorm, double *gnorm,int *flag ) { int ierr; Scalar mone = -1.0; PetscFunctionBegin; *flag = 0; PLogEventBegin(SNES_LineSearch,snes,x,f,g); ierr = VecNorm(y,NORM_2,ynorm); CHKERRQ(ierr); /* ynorm = || y || */ ierr = VecAYPX(&mone,x,y); CHKERRQ(ierr); /* y <- y - x */ ierr = SNESComputeFunction(snes,y,g); CHKERRQ(ierr); /* Compute F(y) */ ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); /* gnorm = || g || */ PLogEventEnd(SNES_LineSearch,snes,x,f,g); PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ #undef __FUNC__ #define __FUNC__ "SNESNoLineSearchNoNorms" /*@C SNESNoLineSearchNoNorms - This routine is not a line search at all; it simply uses the full Newton step. This version does not even compute the norm of the function or search direction; this is intended only when you know the full step is fine and are not checking for convergence of the nonlinear iteration (for example, you are running always for a fixed number of Newton steps). Collective on SNES and Vec Input Parameters: + snes - nonlinear context . x - current iterate . f - residual evaluated at x . y - search direction (contains new iterate on output) . w - work vector - fnorm - 2-norm of f Output Parameters: + g - residual evaluated at new iterate y . gnorm - not changed . ynorm - not changed - flag - set to 0, indicating a successful line search Options Database Key: . -snes_eq_ls basicnonorms - Activates SNESNoLineSearchNoNorms() .keywords: SNES, nonlinear, line search, cubic .seealso: SNESCubicLineSearch(), SNESQuadraticLineSearch(), SNESSetLineSearch(), SNESNoLineSearch() @*/ int SNESNoLineSearchNoNorms(SNES snes, Vec x, Vec f, Vec g, Vec y, Vec w, double fnorm, double *ynorm, double *gnorm,int *flag ) { int ierr; Scalar mone = -1.0; PetscFunctionBegin; *flag = 0; PLogEventBegin(SNES_LineSearch,snes,x,f,g); ierr = VecAYPX(&mone,x,y); CHKERRQ(ierr); /* y <- y - x */ ierr = SNESComputeFunction(snes,y,g); CHKERRQ(ierr); /* Compute F(y) */ PLogEventEnd(SNES_LineSearch,snes,x,f,g); PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ #undef __FUNC__ #define __FUNC__ "SNESCubicLineSearch" /*@C SNESCubicLineSearch - Performs a cubic line search (default line search method). Collective on SNES Input Parameters: + snes - nonlinear context . x - current iterate . f - residual evaluated at x . y - search direction (contains new iterate on output) . w - work vector - fnorm - 2-norm of f Output Parameters: + g - residual evaluated at new iterate y . y - new iterate (contains search direction on input) . gnorm - 2-norm of g . ynorm - 2-norm of search length - flag - 0 if line search succeeds; -1 on failure. Options Database Key: $ -snes_eq_ls cubic - Activates SNESCubicLineSearch() Notes: This line search is taken from "Numerical Methods for Unconstrained Optimization and Nonlinear Equations" by Dennis and Schnabel, page 325. .keywords: SNES, nonlinear, line search, cubic .seealso: SNESNoLineSearch(), SNESNoLineSearch(), SNESSetLineSearch() @*/ int SNESCubicLineSearch(SNES snes,Vec x,Vec f,Vec g,Vec y,Vec w, double fnorm,double *ynorm,double *gnorm,int *flag) { /* Note that for line search purposes we work with with the related minimization problem: min z(x): R^n -> R, where z(x) = .5 * fnorm*fnorm, and fnorm = || f ||_2. */ double steptol, initslope, lambdaprev, gnormprev, a, b, d, t1, t2; double maxstep, minlambda, alpha, lambda, lambdatemp, lambdaneg; #if defined(USE_PETSC_COMPLEX) Scalar cinitslope, clambda; #endif int ierr, count; SNES_LS *neP = (SNES_LS *) snes->data; Scalar mone = -1.0,scale; PetscFunctionBegin; PLogEventBegin(SNES_LineSearch,snes,x,f,g); *flag = 0; alpha = neP->alpha; maxstep = neP->maxstep; steptol = neP->steptol; ierr = VecNorm(y,NORM_2,ynorm); CHKERRQ(ierr); if (*ynorm < snes->atol) { PLogInfo(snes,"SNESCubicLineSearch: Search direction and size are nearly 0\n"); *gnorm = fnorm; ierr = VecCopy(x,y); CHKERRQ(ierr); ierr = VecCopy(f,g); CHKERRQ(ierr); goto theend1; } if (*ynorm > maxstep) { /* Step too big, so scale back */ scale = maxstep/(*ynorm); #if defined(USE_PETSC_COMPLEX) PLogInfo(snes,"SNESCubicLineSearch: Scaling step by %g\n",PetscReal(scale)); #else PLogInfo(snes,"SNESCubicLineSearch: Scaling step by %g\n",scale); #endif ierr = VecScale(&scale,y); CHKERRQ(ierr); *ynorm = maxstep; } minlambda = steptol/(*ynorm); ierr = MatMult(snes->jacobian,y,w); CHKERRQ(ierr); #if defined(USE_PETSC_COMPLEX) ierr = VecDot(f,w,&cinitslope); CHKERRQ(ierr); initslope = PetscReal(cinitslope); #else ierr = VecDot(f,w,&initslope); CHKERRQ(ierr); #endif if (initslope > 0.0) initslope = -initslope; if (initslope == 0.0) initslope = -1.0; ierr = VecCopy(y,w); CHKERRQ(ierr); ierr = VecAYPX(&mone,x,w); CHKERRQ(ierr); ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); ierr = VecNorm(g,NORM_2,gnorm); if ((*gnorm)*(*gnorm)*0.5 <= fnorm*fnorm*0.5 + alpha*initslope) { /* Sufficient reduction */ ierr = VecCopy(w,y); CHKERRQ(ierr); PLogInfo(snes,"SNESCubicLineSearch: Using full step\n"); goto theend1; } /* Fit points with quadratic */ lambda = 1.0; count = 0; lambdatemp = -initslope/((*gnorm)*(*gnorm) - fnorm*fnorm - 2.0*initslope); lambdaprev = lambda; gnormprev = *gnorm; if (lambdatemp <= .1*lambda) lambda = .1*lambda; else lambda = lambdatemp; ierr = VecCopy(x,w); CHKERRQ(ierr); lambdaneg = -lambda; #if defined(USE_PETSC_COMPLEX) clambda = lambdaneg; ierr = VecAXPY(&clambda,y,w); CHKERRQ(ierr); #else ierr = VecAXPY(&lambdaneg,y,w); CHKERRQ(ierr); #endif ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); if ((*gnorm)*(*gnorm)*0.5 <= fnorm*fnorm*0.5 + alpha*initslope) { /* sufficient reduction */ ierr = VecCopy(w,y); CHKERRQ(ierr); PLogInfo(snes,"SNESCubicLineSearch: Quadratically determined step, lambda=%g\n",lambda); goto theend1; } /* Fit points with cubic */ count = 1; while (1) { if (lambda <= minlambda) { /* bad luck; use full step */ PLogInfo(snes,"SNESCubicLineSearch:Unable to find good step length! %d \n",count); PLogInfo(snes,"SNESCubicLineSearch:fnorm=%g, gnorm=%g, ynorm=%g, lambda=%g, initial slope=%g\n", fnorm,*gnorm,*ynorm,lambda,initslope); ierr = VecCopy(w,y); CHKERRQ(ierr); *flag = -1; break; } t1 = ((*gnorm)*(*gnorm) - fnorm*fnorm)*0.5 - lambda*initslope; t2 = (gnormprev*gnormprev - fnorm*fnorm)*0.5 - lambdaprev*initslope; a = (t1/(lambda*lambda) - t2/(lambdaprev*lambdaprev))/(lambda-lambdaprev); b = (-lambdaprev*t1/(lambda*lambda) + lambda*t2/(lambdaprev*lambdaprev))/(lambda-lambdaprev); d = b*b - 3*a*initslope; if (d < 0.0) d = 0.0; if (a == 0.0) { lambdatemp = -initslope/(2.0*b); } else { lambdatemp = (-b + sqrt(d))/(3.0*a); } if (lambdatemp > .5*lambda) { lambdatemp = .5*lambda; } lambdaprev = lambda; gnormprev = *gnorm; if (lambdatemp <= .1*lambda) { lambda = .1*lambda; } else lambda = lambdatemp; ierr = VecCopy( x, w ); CHKERRQ(ierr); lambdaneg = -lambda; #if defined(USE_PETSC_COMPLEX) clambda = lambdaneg; ierr = VecAXPY(&clambda,y,w); CHKERRQ(ierr); #else ierr = VecAXPY(&lambdaneg,y,w); CHKERRQ(ierr); #endif ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); if ((*gnorm)*(*gnorm)*0.5 <= fnorm*fnorm*0.5 + alpha*initslope) { /* is reduction enough? */ ierr = VecCopy(w,y); CHKERRQ(ierr); PLogInfo(snes,"SNESCubicLineSearch: Cubically determined step, lambda=%g\n",lambda); goto theend1; } else { PLogInfo(snes,"SNESCubicLineSearch: Cubic step no good, shrinking lambda, lambda=%g\n",lambda); } count++; } theend1: PLogEventEnd(SNES_LineSearch,snes,x,f,g); PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ #undef __FUNC__ #define __FUNC__ "SNESQuadraticLineSearch" /*@C SNESQuadraticLineSearch - Performs a quadratic line search. Collective on SNES and Vec Input Parameters: + snes - the SNES context . x - current iterate . f - residual evaluated at x . y - search direction (contains new iterate on output) . w - work vector - fnorm - 2-norm of f Output Parameters: + g - residual evaluated at new iterate y . y - new iterate (contains search direction on input) . gnorm - 2-norm of g . ynorm - 2-norm of search length - flag - 0 if line search succeeds; -1 on failure. Options Database Key: . -snes_eq_ls quadratic - Activates SNESQuadraticLineSearch() Notes: Use SNESSetLineSearch() to set this routine within the SNES_EQ_LS method. .keywords: SNES, nonlinear, quadratic, line search .seealso: SNESCubicLineSearch(), SNESNoLineSearch(), SNESSetLineSearch() @*/ int SNESQuadraticLineSearch(SNES snes, Vec x, Vec f, Vec g, Vec y, Vec w, double fnorm, double *ynorm, double *gnorm,int *flag) { /* Note that for line search purposes we work with with the related minimization problem: min z(x): R^n -> R, where z(x) = .5 * fnorm*fnorm, and fnorm = || f ||_2. */ double steptol,initslope,maxstep,minlambda,alpha,lambda,lambdatemp; #if defined(USE_PETSC_COMPLEX) Scalar cinitslope,clambda; #endif int ierr,count; SNES_LS *neP = (SNES_LS *) snes->data; Scalar mone = -1.0,scale; PetscFunctionBegin; PLogEventBegin(SNES_LineSearch,snes,x,f,g); *flag = 0; alpha = neP->alpha; maxstep = neP->maxstep; steptol = neP->steptol; VecNorm(y, NORM_2,ynorm ); if (*ynorm < snes->atol) { PLogInfo(snes,"SNESQuadraticLineSearch: Search direction and size is 0\n"); *gnorm = fnorm; ierr = VecCopy(x,y); CHKERRQ(ierr); ierr = VecCopy(f,g); CHKERRQ(ierr); goto theend2; } if (*ynorm > maxstep) { /* Step too big, so scale back */ scale = maxstep/(*ynorm); ierr = VecScale(&scale,y); CHKERRQ(ierr); *ynorm = maxstep; } minlambda = steptol/(*ynorm); ierr = MatMult(snes->jacobian,y,w); CHKERRQ(ierr); #if defined(USE_PETSC_COMPLEX) ierr = VecDot(f,w,&cinitslope); CHKERRQ(ierr); initslope = PetscReal(cinitslope); #else ierr = VecDot(f,w,&initslope); CHKERRQ(ierr); #endif if (initslope > 0.0) initslope = -initslope; if (initslope == 0.0) initslope = -1.0; ierr = VecCopy(y,w); CHKERRQ(ierr); ierr = VecAYPX(&mone,x,w); CHKERRQ(ierr); ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); if ((*gnorm)*(*gnorm)*0.5 <= fnorm*fnorm*0.5 + alpha*initslope) { /* Sufficient reduction */ ierr = VecCopy(w,y); CHKERRQ(ierr); PLogInfo(snes,"SNESQuadraticLineSearch: Using full step\n"); goto theend2; } /* Fit points with quadratic */ lambda = 1.0; count = 0; count = 1; while (1) { if (lambda <= minlambda) { /* bad luck; use full step */ PLogInfo(snes,"SNESQuadraticLineSearch:Unable to find good step length! %d \n",count); PLogInfo(snes,"SNESQuadraticLineSearch:fnorm=%g, gnorm=%g, ynorm=%g, lambda=%g, initial slope=%g\n", fnorm,*gnorm,*ynorm,lambda,initslope); ierr = VecCopy(w,y); CHKERRQ(ierr); *flag = -1; break; } lambdatemp = -initslope/((*gnorm)*(*gnorm) - fnorm*fnorm - 2.0*initslope); if (lambdatemp <= .1*lambda) { lambda = .1*lambda; } else lambda = lambdatemp; ierr = VecCopy(x,w); CHKERRQ(ierr); lambda = -lambda; #if defined(USE_PETSC_COMPLEX) clambda = lambda; ierr = VecAXPY(&clambda,y,w); CHKERRQ(ierr); #else ierr = VecAXPY(&lambda,y,w); CHKERRQ(ierr); #endif ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); if ((*gnorm)*(*gnorm)*0.5 <= fnorm*fnorm*0.5 + alpha*initslope) { /* sufficient reduction */ ierr = VecCopy(w,y); CHKERRQ(ierr); PLogInfo(snes,"SNESQuadraticLineSearch:Quadratically determined step, lambda=%g\n",lambda); break; } count++; } theend2: PLogEventEnd(SNES_LineSearch,snes,x,f,g); PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ #undef __FUNC__ #define __FUNC__ "SNESSetLineSearch" /*@C SNESSetLineSearch - Sets the line search routine to be used by the method SNES_EQ_LS. Input Parameters: + snes - nonlinear context obtained from SNESCreate() - func - pointer to int function Collective on SNES Available Routines: + SNESCubicLineSearch() - default line search . SNESQuadraticLineSearch() - quadratic line search . SNESNoLineSearch() - the full Newton step (actually not a line search) - SNESNoLineSearchNoNorms() - use the full Newton step (calculate no norms; faster in parallel) Options Database Keys: + -snes_eq_ls [basic,quadratic,cubic] - Selects line search . -snes_eq_ls_alpha - Sets alpha . -snes_eq_ls_maxstep - Sets maxstep - -snes_eq_ls_steptol - Sets steptol Calling sequence of func: .vb func (SNES snes, Vec x, Vec f, Vec g, Vec y, Vec w, double fnorm, double *ynorm, double *gnorm, *flag) .ve Input parameters for func: + snes - nonlinear context . x - current iterate . f - residual evaluated at x . y - search direction (contains new iterate on output) . w - work vector - fnorm - 2-norm of f Output parameters for func: + g - residual evaluated at new iterate y . y - new iterate (contains search direction on input) . gnorm - 2-norm of g . ynorm - 2-norm of search length - flag - set to 0 if the line search succeeds; a nonzero integer on failure. .keywords: SNES, nonlinear, set, line search, routine .seealso: SNESNoLineSearch(), SNESQuadraticLineSearch(), SNESCubicLineSearch() @*/ int SNESSetLineSearch(SNES snes,int (*func)(SNES,Vec,Vec,Vec,Vec,Vec, double,double*,double*,int*)) { int ierr, (*f)(SNES,int (*)(SNES,Vec,Vec,Vec,Vec,Vec,double,double*,double*,int*)); PetscFunctionBegin; ierr = PetscObjectQueryFunction((PetscObject)snes,"SNESSetLineSearch_C",(void **)&f);CHKERRQ(ierr); if (f) { ierr = (*f)(snes,func);CHKERRQ(ierr); } PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ #undef __FUNC__ #define __FUNC__ "SNESSetLineSearch_LS" int SNESSetLineSearch_LS(SNES snes,int (*func)(SNES,Vec,Vec,Vec,Vec,Vec, double,double*,double*,int*)) { PetscFunctionBegin; ((SNES_LS *)(snes->data))->LineSearch = func; PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ /* SNESPrintHelp_EQ_LS - Prints all options for the SNES_EQ_LS method. Input Parameter: . snes - the SNES context Application Interface Routine: SNESPrintHelp() */ #undef __FUNC__ #define __FUNC__ "SNESPrintHelp_EQ_LS" static int SNESPrintHelp_EQ_LS(SNES snes,char *p) { SNES_LS *ls = (SNES_LS *)snes->data; PetscFunctionBegin; (*PetscHelpPrintf)(snes->comm," method SNES_EQ_LS (ls) for systems of nonlinear equations:\n"); (*PetscHelpPrintf)(snes->comm," %ssnes_eq_ls [basic,quadratic,cubic]\n",p); (*PetscHelpPrintf)(snes->comm," %ssnes_eq_ls_alpha (default %g)\n",p,ls->alpha); (*PetscHelpPrintf)(snes->comm," %ssnes_eq_ls_maxstep (default %g)\n",p,ls->maxstep); (*PetscHelpPrintf)(snes->comm," %ssnes_eq_ls_steptol (default %g)\n",p,ls->steptol); PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ /* SNESView_EQ_LS - Prints the SNES_EQ_LS data structure. Input Parameters: . SNES - the SNES context . viewer - visualization context Application Interface Routine: SNESView() */ #undef __FUNC__ #define __FUNC__ "SNESView_EQ_LS" static int SNESView_EQ_LS(SNES snes,Viewer viewer) { SNES_LS *ls = (SNES_LS *)snes->data; FILE *fd; char *cstr; int ierr; ViewerType vtype; PetscFunctionBegin; ierr = ViewerGetType(viewer,&vtype); CHKERRQ(ierr); if (vtype == ASCII_FILE_VIEWER || vtype == ASCII_FILES_VIEWER) { ierr = ViewerASCIIGetPointer(viewer,&fd); CHKERRQ(ierr); if (ls->LineSearch == SNESNoLineSearch) cstr = "SNESNoLineSearch"; else if (ls->LineSearch == SNESQuadraticLineSearch) cstr = "SNESQuadraticLineSearch"; else if (ls->LineSearch == SNESCubicLineSearch) cstr = "SNESCubicLineSearch"; else cstr = "unknown"; PetscFPrintf(snes->comm,fd," line search variant: %s\n",cstr); PetscFPrintf(snes->comm,fd," alpha=%g, maxstep=%g, steptol=%g\n", ls->alpha,ls->maxstep,ls->steptol); } else { SETERRQ(1,1,"Viewer type not supported for this object"); } PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ /* SNESSetFromOptions_EQ_LS - Sets various parameters for the SNES_EQ_LS method. Input Parameter: . snes - the SNES context Application Interface Routine: SNESSetFromOptions() */ #undef __FUNC__ #define __FUNC__ "SNESSetFromOptions_EQ_LS" static int SNESSetFromOptions_EQ_LS(SNES snes) { SNES_LS *ls = (SNES_LS *)snes->data; char ver[16]; double tmp; int ierr,flg; PetscFunctionBegin; ierr = OptionsGetDouble(snes->prefix,"-snes_eq_ls_alpha",&tmp, &flg);CHKERRQ(ierr); if (flg) { ls->alpha = tmp; } ierr = OptionsGetDouble(snes->prefix,"-snes_eq_ls_maxstep",&tmp, &flg);CHKERRQ(ierr); if (flg) { ls->maxstep = tmp; } ierr = OptionsGetDouble(snes->prefix,"-snes_eq_ls_steptol",&tmp, &flg);CHKERRQ(ierr); if (flg) { ls->steptol = tmp; } ierr = OptionsGetString(snes->prefix,"-snes_eq_ls",ver,16, &flg); CHKERRQ(ierr); if (flg) { if (!PetscStrcmp(ver,"basic")) { SNESSetLineSearch(snes,SNESNoLineSearch); } else if (!PetscStrcmp(ver,"basicnonorms")) { SNESSetLineSearch(snes,SNESNoLineSearchNoNorms); } else if (!PetscStrcmp(ver,"quadratic")) { SNESSetLineSearch(snes,SNESQuadraticLineSearch); } else if (!PetscStrcmp(ver,"cubic")) { SNESSetLineSearch(snes,SNESCubicLineSearch); } else {SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,0,"Unknown line search");} } PetscFunctionReturn(0); } /* -------------------------------------------------------------------------- */ /* SNESCreate_EQ_LS - Creates a nonlinear solver context for the SNES_EQ_LS method, SNES_LS, and sets this as the private data within the generic nonlinear solver context, SNES, that was created within SNESCreate(). Input Parameter: . snes - the SNES context Application Interface Routine: SNESCreate() */ #undef __FUNC__ #define __FUNC__ "SNESCreate_EQ_LS" int SNESCreate_EQ_LS(SNES snes) { int ierr; SNES_LS *neP; PetscFunctionBegin; if (snes->method_class != SNES_NONLINEAR_EQUATIONS) { SETERRQ(PETSC_ERR_ARG_WRONG,0,"For SNES_NONLINEAR_EQUATIONS only"); } snes->setup = SNESSetUp_EQ_LS; snes->solve = SNESSolve_EQ_LS; snes->destroy = SNESDestroy_EQ_LS; snes->converged = SNESConverged_EQ_LS; snes->printhelp = SNESPrintHelp_EQ_LS; snes->setfromoptions = SNESSetFromOptions_EQ_LS; snes->view = SNESView_EQ_LS; snes->nwork = 0; neP = PetscNew(SNES_LS); CHKPTRQ(neP); PLogObjectMemory(snes,sizeof(SNES_LS)); snes->data = (void *) neP; neP->alpha = 1.e-4; neP->maxstep = 1.e8; neP->steptol = 1.e-12; neP->LineSearch = SNESCubicLineSearch; ierr = PetscObjectComposeFunction((PetscObject)snes,"SNESSetLineSearch_C","SNESSetLineSearch_LS", (void*)SNESSetLineSearch_LS);CHKERRQ(ierr); PetscFunctionReturn(0); }