64   PetscReal          lambda, lambdatemp, lambdaprev, minlambda, initslope, alpha, stol;  in SNESLineSearchApply_BT()  local
120     PetscCall(VecDotRealPart(Y, F, &initslope));  in SNESLineSearchApply_BT()
124     PetscCall(VecDotRealPart(F, W, &initslope));  in SNESLineSearchApply_BT()
125     if (initslope > 0.0) initslope = -initslope;  in SNESLineSearchApply_BT()
126     if (initslope == 0.0) initslope = -1.0;  in SNESLineSearchApply_BT()
165 …if (g <= f + lambda * alpha * initslope) { /* Sufficient reduction or step tolerance convergence */  in SNESLineSearchApply_BT()
192       lambdatemp = -initslope * PetscSqr(lambda) / (2.0 * (g - f - lambda * initslope));  in SNESLineSearchApply_BT()
232 …if (linesearch->order != SNES_LINESEARCH_ORDER_LINEAR && g <= f + lambda * alpha * initslope) { /*…  in SNESLineSearchApply_BT()
245 …double)fnorm, (double)gnorm, (double)ynorm, (double)minlambda, (double)lambda, (double)initslope));  in SNESLineSearchApply_BT()
247 …6e\n", (double)f, (double)g, (double)ynorm, (double)minlambda, (double)lambda, (double)initslope));  in SNESLineSearchApply_BT()
256           t1 = g - f - lambda * initslope;  in SNESLineSearchApply_BT()
257           t2 = gprev - f - lambdaprev * initslope;  in SNESLineSearchApply_BT()
260           d  = b * b - 3 * a * initslope;  in SNESLineSearchApply_BT()
262           if (a == 0.0) lambdatemp = -initslope / (2.0 * b);  in SNESLineSearchApply_BT()
265           lambdatemp = -initslope * PetscSqr(lambda) / (2.0 * (g - f - lambda * initslope));  in SNESLineSearchApply_BT()
277 …slope=%18.16e\n", (double)fnorm, (double)gnorm, (double)ynorm, (double)lambda, (double)initslope));  in SNESLineSearchApply_BT()
296         if (g <= f + lambda * alpha * initslope) { /* is reduction enough? */  in SNESLineSearchApply_BT()