Index: /issm/trunk-jpl/src/c/cores/transient_core.cpp
===================================================================
--- /issm/trunk-jpl/src/c/cores/transient_core.cpp	(revision 25559)
+++ /issm/trunk-jpl/src/c/cores/transient_core.cpp	(revision 25560)
@@ -276,4 +276,5 @@
 	bool       isoceancoupling,isslr;
 	int        step,timestepping;
+	int        recording_frequency,finalcheckpoint;
 	DataSet*   dependent_objects=NULL;
 
@@ -286,4 +287,5 @@
 	femmodel->parameters->FindParam(&isslr,TransientIsslrEnum);
 	femmodel->parameters->FindParam(&dependent_objects,AutodiffDependentObjectsEnum);
+	femmodel->parameters->FindParam(&recording_frequency,SettingsRecordingFrequencyEnum); _assert_(recording_frequency>0);
 	if(isslr) sealevelrise_core_geometry(femmodel);
 
@@ -298,6 +300,16 @@
 
 		/*Time Increment*/
-		if(timestepping!=FixedTimesteppingEnum) _error_("not supported yet, but easy to handle...");
-		femmodel->parameters->FindParam(&dt,TimesteppingTimeStepEnum);
+		switch(timestepping){
+			case AdaptiveTimesteppingEnum:
+				femmodel->TimeAdaptx(&dt);
+				if(time+dt>finaltime) dt=finaltime-time;
+				femmodel->parameters->SetParam(dt,TimesteppingTimeStepEnum);
+				break;
+			case FixedTimesteppingEnum:
+				femmodel->parameters->FindParam(&dt,TimesteppingTimeStepEnum);
+				break;
+			default:
+				_error_("Time stepping \""<<EnumToStringx(timestepping)<<"\" not supported yet");
+		}
 		step+=1;
 		time+=dt;
@@ -307,7 +319,15 @@
 		time_all.push_back(time);
 
+		if(VerboseSolution()){
+			_printf0_("iteration " << step << "/" << ceil((finaltime-time)/dt)+step << \
+						"  time [yr]: " <<std::fixed<<setprecision(2)<< time/yts << " (time step: " << dt/yts << ")\n");
+		}
+
 		/*Store Model State at the beginning of the step*/
-		if(VerboseSolution()) _printf0_("   checkpointing model \n");
-		femmodel->CheckPointAD(step);
+		if(step%recording_frequency==0){
+			if(VerboseSolution()) _printf0_("   checkpointing model (step: "<<step<<")\n");
+			femmodel->CheckPointAD(step);
+			finalcheckpoint = step;
+		}
 
 		if(VerboseSolution()) _printf0_("   counting number of active variables\n");
@@ -328,4 +348,5 @@
 	}
 
+	int finalstep = step;
 	if(VerboseSolution()) _printf0_("   done with initial complete transient\n");
 
@@ -366,5 +387,5 @@
 	}
 	else{
-		femmodel->IceVolumex(&J,false);
+		femmodel->IceVolumeAboveFloatationx(&J,false);
 	}
 	if(IssmComm::GetRank()==0) tape_codi.registerOutput(J);
@@ -380,5 +401,5 @@
 
 	/*reverse loop for transient step (G)*/
-	for(int reverse_step = step;reverse_step>0; reverse_step--){
+	for(int reverse_step = finalcheckpoint;reverse_step>0; reverse_step-=recording_frequency){
 
 		/*Restore model from this step*/
@@ -403,5 +424,11 @@
 
 		/*Get New state*/
-		transient_step(femmodel);
+		for(int ii=0;ii<recording_frequency;ii++){
+			int        thisstep = reverse_step+ii;
+			IssmDouble thistime = time_all[reverse_step+ii-1];
+			_printf0_("step "<<thisstep<<" ("<<ii+1<<"/"<<recording_frequency<<") time [yr]: "<<std::fixed<<std::setprecision(2)<<thistime/yts<<"\n");
+			transient_step(femmodel);
+			if(thisstep==finalstep) break;
+		}
 
 		/*Register output*/
@@ -422,5 +449,4 @@
 
 		/* here we access the gradient data via the stored identifiers.*/
-		//for(int i=0; i<Ysize_i; i++) if(tape_codi.gradient(Yin[i])!=0.) printf(" %g (%i)",tape_codi.gradient(Yin[i]),Yin[i]);
 		for(int i=0; i<Ysize_i; i++) Yb[i]  = tape_codi.gradient(Yin[i]);
 		for(int i=0; i<Xsize;   i++) Xb[i] += X[i].gradient();