diff --git a/src/CalculateE.c b/src/CalculateE.c
index f4b90baf..d72bde04 100644
--- a/src/CalculateE.c
+++ b/src/CalculateE.c
@@ -222,6 +222,7 @@ void MuellerMatrix(void)
 
 	// redundant initialization to remove warnings
 	mueller=ampl=NULL;
+	co=si=0;
 
 	// Everything is done on ROOT only
 	if (!IFROOT) return;
diff --git a/src/Makefile b/src/Makefile
index 4c7dd08f..31f6415b 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -41,6 +41,11 @@ PROGSEQ  = adda
 PROGMPI  = adda_mpi
 # Targets implying compilation (empty one is always included)
 NONTRIVIAL = all seq mpi
+# targets implying sequential or mpi compilation. This duplicates the functionality of the target
+# designation, but is required for timely update of .lastopts
+SEQGOALS = seq all
+MPIGOALS = mpi all
+LASTOPTSFILE = .lastopts
 
 #===================================================================================================
 # !!! Start of control section. Flags and options here can be modified by user. However, the default
@@ -67,11 +72,16 @@ ifneq ($(if $(MAKECMDGOALS),$(if $(filter $(NONTRIVIAL),$(MAKECMDGOALS)),1,),1),
 # separated by spaces, e.g. 'make OPTIONS="DEBUG FFT_TEMPERTON" ...'. OPTIONS that are uncommented
 # below are appended to the list specified elsewhere.
 # Full list of possible options is the following:
-VALID_OPTS=DEBUG FFT_TEMPERTON PRECISE_TIMING NOT_USE_LOCK ONLY_LOCKFILE NO_FORTRAN \
+VALID_OPTS=DEBUG DEBUGFULL FFT_TEMPERTON PRECISE_TIMING NOT_USE_LOCK ONLY_LOCKFILE NO_FORTRAN \
            OVERRIDE_STDC_TEST
 
-# Debug mode (debug.h).
+# Debug mode. By default, release configuration is used (no debug, no warnings, maximum
+# optimization). DEBUG turns on producing debugging symbols (-g) and warnings and brings
+# optimization down to O2 (this is required to produce all possible warnings by the compiler).
+# DEBUGFULL turns off optimization completely (for more accurate debugging symbols) and turns on
+# additional diagnostic messages in the source code (debug.c/h).
 #override OPTIONS += DEBUG
+#override OPTIONS += DEBUGFULL
 
 # Temperton FFT (fft.h).
 #override OPTIONS += FFT_TEMPERTON
@@ -111,9 +121,6 @@ COMPILER = gnu
 # command line of make (see explanation above for OPTIONS).
 override EXTRA_CFLAGS +=
 
-# --Warnings-- If uncommented, all warning are suppressed
-RELEASE = on
-
 # --FFTW3 paths--
 # Specify path to headers and libraries of FFTW3. Some systems do not need them at all, some specify
 # special global variables (first or second 2 lines), on some - FFTW3 is installed under user
@@ -177,9 +184,20 @@ $(foreach var,$(filter-out $(VALID_OPTS),$(OPTIONS)),\
               $(warning The option '$(var)' is not recognized. Please check the spelling.))
 
 $(info --- Compilation options: ---)
-ifneq ($(filter DEBUG,$(OPTIONS)),)
+ifneq ($(filter DEBUGFULL,$(OPTIONS)),)
+  $(info Full debug mode)
+  DBGLVL = 2
+  CDEFS += -DDEBUGFULL
+  ifneq ($(filter DEBUG,$(OPTIONS)),)
+    $(warning DEBUG has no effect when DEBUGFULL is enabled)
+  endif
+else ifneq ($(filter DEBUG,$(OPTIONS)),)
   $(info Debug mode)
+  DBGLVL = 1
   CDEFS += -DDEBUG
+else
+  $(info Release mode)
+  DBGLVL = 0
 endif
 ifneq ($(filter FFT_TEMPERTON,$(OPTIONS)),)
   $(info Temperton FFT)
@@ -241,22 +259,26 @@ ifeq ($(COMPILER),gnu)
   # You can add '-march=...' or 'mcpu=...' to COPT and FOPT in this section
   CC    = gcc
   CF    = g77
-  COPT  = -std=c99 -O3 -ffast-math -funroll-loops
+  CSTD  = -std=c99
+  CDBG  = -g
+  COPT1 = -O2
+  COPT2 = -O3 -ffast-math -funroll-loops
+  CWARN = -Wall -Wextra -pedantic -Wcast-qual -Wpointer-arith -Wwrite-strings -Wstrict-prototypes \
+          -Wstrict-aliasing=1 -Wshadow -Wcast-align -Wnested-externs -Wcomment -Wno-unknown-pragmas
   FOPT  = -O
   FLIBS += -lg2c
-  CWARN = -Wall -Wextra -pedantic -Wcast-qual -Wpointer-arith \
-          -Wwrite-strings -Wstrict-prototypes -Wstrict-aliasing=1 -Wshadow \
-          -Wcast-align -Wnested-externs -Wcomment \
-          -Wno-unknown-pragmas
 
 else ifeq ($(COMPILER),intel)
   CC    = icc
   CF    = ifort
-  COPT  = -std=c99 -O3
+  CSTD  = -std=c99
+  CDBG  = -g
+  COPT1 = -O2
+  COPT2 = -O3
+  CWARN = -Wall -Wcheck -diag-disable 981,1418,1419,1572,2259 -vec-report0
   FOPT  = -O3
   FWARN += -vec-report0
   FLIBS += -lifcore
-  CWARN = -Wall -Wcheck -diag-disable 981,1418,1419,1572,2259 -vec-report0
   # if IPO is used, corresponding flags should be added to linker options: LDFLAGS += ...
 else ifeq ($(COMPILER),compaq)
   # This compiler was not tested since 2007. In particular, warning options may not fit exactly the
@@ -266,7 +288,10 @@ else ifeq ($(COMPILER),compaq)
   # You can add option '-arch host' to COPT and FOPT in this section
   CC    = cc
   CF    = f77
-  COPT  = -fast
+  #CSTD  = -std=c99
+  CDBG  = -g
+  COPT1 = -O2
+  COPT2 = -fast
   CWARN = -w0 -msg_disable nestedcomment,unknownpragma,unreachcode
 else ifeq ($(COMPILER),ibm)
   # This compiler was not tested since 2008. In particular, it is not clear, whether and what FLIBS
@@ -277,15 +302,20 @@ else ifeq ($(COMPILER),ibm)
   # Then use '-O3 -qarch=... -qtune=...' instead
   CC      = xlc
   CF      = xlf
-  COPT    = -O3 -qcache=auto -qlanglvl=extc99
+  CSTD  = -qlanglvl=extc99
+  CDBG  = -g
+  COPT1 = -O2
+  COPT2 = -O3 -qcache=auto
   # DFREDIRECT = 2>nul -qipa=level=2 -qhot
   DEPFLAG = -qmakedep=gcc -qsyntaxonly
   CWARN   = -qsuppress=1506-224:1506-342:1500-036
 else ifeq ($(COMPILER),hpux)
   CC    = cc
   CF    = f90
-  FOPT  = +O3  +DD64
-  COPT  =  -AC99 +O3  +DD64
+  CSTD  = -AC99
+  CDBG  = -g
+  COPT1 = +O2 +DD64
+  COPT2 = +O3 +DD64
   CWARN =
   CFLAGS += -DNOT_USE_LOCK
 else ifeq ($(COMPILER),other)
@@ -300,17 +330,35 @@ ifneq ($(strip $(FSOURCE)),)
   LDLIBS += $(FLIBS)
 endif
 # if 'release' turn off warningns
-ifdef RELEASE
-  $(info All warnings are suppressed)
+ifeq ($(DBGLVL),0)
   CWARN = -w
   LDFLAGS += -w
+  COPT = $(COPT2)
+  CDBG =
+else ifeq ($(DBGLVL),1)
+  COPT = $(COPT1)
+else ifeq ($(DBGLVL),2)
+  COPT =
 endif
 # Finalize option flags (almost)
-CFLAGS += $(COPT) $(CWARN)
+CFLAGS += $(CSTD) $(CDBG) $(COPT) $(CWARN)
 FFLAGS += $(FOPT) $(FWARN)
 
 FOBJECTS = $(FSOURCE:.f=.o)
 
+ifneq ($(if $(MAKECMDGOALS),$(if $(filter $(SEQGOALS),$(MAKECMDGOALS)),1,),1),)
+  -include $(SEQ)/$(LASTOPTSFILE)
+  ifneq ($(strip $(filter-out $(LASTOPTS),$(OPTIONS)) $(filter-out $(OPTIONS),$(LASTOPTS))),)
+    $(shell rm -f $(SEQ)/$(LASTOPTSFILE))
+  endif
+endif
+ifneq ($(if $(MAKECMDGOALS),$(if $(filter $(MPIGOALS),$(MAKECMDGOALS)),1,),1),)
+  -include $(MPI)/$(LASTOPTSFILE)
+  ifneq ($(strip $(filter-out $(LASTOPTS),$(OPTIONS)) $(filter-out $(OPTIONS),$(LASTOPTS))),)
+    $(shell rm -f $(MPI)/$(LASTOPTSFILE))
+  endif
+endif
+
 $(info ----------------------------)
 
 #===================================================================================================
@@ -337,8 +385,8 @@ clean: cleanseq cleanmpi
 # Moving 'clean' commands to child makefiles is problematic due to included dependency files
 cleanseq:
 	@echo "Removing sequential compiled files"
-	cd $(SEQ) && rm -f *.o *.d $(PROGSEQ) $(PROGSEQ).exe
+	cd $(SEQ) && rm -f *.o *.d $(LASTOPTSFILE) $(PROGSEQ) $(PROGSEQ).exe
 
 cleanmpi:
 	@echo "Removing MPI compiled files"
-	cd $(MPI) && rm -f *.o *.d $(PROGMPI) $(PROGMPI).exe
+	cd $(MPI) && rm -f *.o *.d $(LASTOPTSFILE) $(PROGMPI) $(PROGMPI).exe
diff --git a/src/Romberg.c b/src/Romberg.c
index 89993578..8b2f1878 100644
--- a/src/Romberg.c
+++ b/src/Romberg.c
@@ -308,7 +308,7 @@ static double InnerRomberg(const int fixed,double * restrict res,const bool onep
 	double err;
 
 	// redundant initialization to remove warnings
-	abs_err=err=0;
+	abs_err=err=int_err=0;
 
 	if (input[PHI].Grid_size==1 ||  onepoint) { // if only one point (really or assumed)
 		int_err=(*func)(fixed,0,res);
@@ -416,7 +416,7 @@ static double OuterRomberg(double * restrict res)
 	double err;
 
 	// redundant initialization to remove warnings
-	err=0;
+	err=int_err=0;
 
 	if (input[THETA].Grid_size==1) { // if only one point
 		N_eval=0;
diff --git a/src/debug.c b/src/debug.c
index 852bec88..e0d55b00 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -1,7 +1,7 @@
 /* File: debug.c
  * $Author$
  * $Date::                            $
- * Descr: functions for printing debugging information when compiling with option -DDEBUG
+ * Descr: functions for printing debugging information when compiling with option -DDEBUGFULL
  *
  *        Previous versions by "vesseur"
  *
@@ -30,7 +30,7 @@
 #include "io.h"
 #include "vars.h"
 
-#ifdef DEBUG
+#ifdef DEBUGFULL
 //============================================================
 
 void DebugPrintf(ERR_LOC_DECL,const char * restrict fmt, ... )
@@ -66,4 +66,4 @@ void FieldPrint (doublecomplex * restrict x)
 	fprintf(logfile,"E = "CFORM3V,x[i][RE],x[i][IM],x[i+1][RE],x[i+1][IM],x[i+2][RE],x[i+2][IM]);
 }
 
-#endif // DEBUG
+#endif // DEBUGFULL
diff --git a/src/debug.h b/src/debug.h
index 49c1ebb7..f3442c4d 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -27,9 +27,9 @@
  * and convenient tool to generate such messages is used.
  */
 
-//#define DEBUG // uncomment to degug
+//#define DEBUGFULL // uncomment to degug
 
-#ifdef DEBUG
+#ifdef DEBUGFULL
 
 #	include "function.h" // for function attributes
 #	include "const.h"    // for POS
diff --git a/src/fft.c b/src/fft.c
index e1fe817d..6ca927cf 100644
--- a/src/fft.c
+++ b/src/fft.c
@@ -43,14 +43,17 @@
  */
 #	define PLAN_FFTW FFTW_MEASURE
 #	define PLAN_FFTW_DM FFTW_ESTIMATE
+#	define ONLY_FOR_FFTW3
+#else
+#	define ONLY_FOR_FFTW3 ATT_UNUSED
 #endif
 // for transpose YZ
 #define TR_BLOCK 64
 
 #ifdef FFT_TEMPERTON
-#define ONLY_FOR_TEMPERTON
+#	define ONLY_FOR_TEMPERTON
 #else
-#define ONLY_FOR_TEMPERTON ATT_UNUSED
+#	define ONLY_FOR_TEMPERTON ATT_UNUSED
 #endif
 
 // SEMI-GLOBAL VARIABLES
@@ -422,7 +425,7 @@ int fftFit(int x,int divis)
 
 //=============================================================
 
-static void fftInitBeforeD(const int lengthZ)
+static void fftInitBeforeD(const int lengthZ ONLY_FOR_FFTW3)
 // initialize fft before initialization of Dmatrix
 {
 #ifdef FFTW3
diff --git a/src/make_particle.c b/src/make_particle.c
index 26e0a08d..cc79925f 100644
--- a/src/make_particle.c
+++ b/src/make_particle.c
@@ -746,7 +746,7 @@ static double PlaceGranules(void)
 	 * small and large granules is largely independent (although there are some common parts, which
 	 * motivates against complete separation of them into two functions).
 	 */
-	zerofit=gX2=gY2=gZ2=locgZ2=id0=id1=jd0=jd1=kd0=kd1=indZ=locgZ=gr_locgN=0;
+	zerofit=gX2=gY2=gZ2=locgZ2=id0=id1=jd0=jd1=kd0=kd1=indZ=locgZ=gr_locgN=sx=sy=sz=0;
 	gdXh=gdYh=gdZh=0;
 	ginX=ginY=ginZ=NULL;
 	dom=NULL;
diff --git a/src/mpi/Makefile b/src/mpi/Makefile
index 80714a4b..0c289e20 100644
--- a/src/mpi/Makefile
+++ b/src/mpi/Makefile
@@ -77,19 +77,22 @@ $(PROGMPI): $(COBJECTS) $(FOBJECTS)
 	@echo "Building $@"
 	$(MPICC) -o $@ $(LDFLAGS) $(COBJECTS) $(FOBJECTS) $(LDLIBS)
 
-# Everything is recompiled when any of makefiles is changed)
-$(COBJECTS): %.o: %.c %.d $(MFILES)
+$(COBJECTS): %.o: %.c %.d
 	$(MPICC) -c $(CFLAGS) $(CDEFS) $<
 
 $(FOBJECTS): %.o: %.f $(MFILES)
 	$(CF) -c $(FFLAGS) $<
 
-# Dependencies are only generated for C sources; we assume that each Fortran file is completely
-# independent or all of them are compiled at once
+# Dependencies are only generated for C sources; we assume that each Fortran file is completely 
+# independent or all of them are compiled at once. 
+# Everything is recompiled when any of makefiles or .lastopts is changed
 
-$(CDEPEND): %.d: %.c $(MFILES)
-	$(MPICC) $(DEPFLAG) $(CFLAGS) $(CDEFS) $< $(DFFLAG) $@.$$$$; \
+$(CDEPEND): %.d: %.c $(MFILES) $(LASTOPTSFILE)
+	$(CC) $(DEPFLAG) $(CFLAGS) $(CDEFS) $< $(DFFLAG) $@.$$$$; \
 	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
 	rm -f $@.$$$$
 
+$(LASTOPTSFILE):
+	echo LASTOPTS = $(OPTIONS) > $@
+
 -include $(CDEPEND)
diff --git a/src/param.c b/src/param.c
index 928991fe..1f06bd4a 100644
--- a/src/param.c
+++ b/src/param.c
@@ -54,8 +54,10 @@
 #	endif
 #	define LOCK_WAIT 1 // in seconds
 #	define MAX_LOCK_WAIT_CYCLES 60
+#	define ONLY_FOR_LOCK
 #else
 #	define FILEHANDLE int
+#	define ONLY_FOR_LOCK ATT_UNUSED
 #endif
 
 // GLOBAL VARIABLES
@@ -350,8 +352,8 @@ static struct opt_struct options[]={
 	{PAR(asym),"","Calculate the asymmetry vector. Implies '-Csca' and '-vec'",0,NULL},
 	{PAR(beam),"<type> [<args>]","Sets a type of the incident beam. Four other float arguments are "
 		"relevant for all beam types except 'plane'. These are the width and x, y, z coordinates of "
-		"the center of the beam respectively (all in um). The latter three can be omitted (then "
-		"beam center is located in the origin).\n"
+		"the center of the beam respectively in the laboratory reference fram (all in um). The "
+		"latter three can be omitted (then beam center is located in the origin).\n"
 		"Default: plane",UNDEF,beam_opt},
 	{PAR(chp_dir),"<dirname>","Sets directory for the checkpoint (both for saving and loading).\n"
 		"Default: "FD_CHP_DIR,1,NULL},
@@ -1348,7 +1350,9 @@ PARSE_FUNC(V)
 		printf(" (%d-bit)\n",bits);
 		// extra build flags
 		strncpy(build_opts,
-#ifdef DEBUG
+#ifdef DEBUGFULL
+		"DEBUGFULL, "
+#elif defined(DEBUG)
 		"DEBUG, "
 #endif
 #ifdef FFT_TEMPERTON
@@ -1417,7 +1421,7 @@ PARSE_FUNC(yz)
 // end of parsing functions
 //=============================================================
 
-static FILEHANDLE CreateLockFile(const char * restrict fname)
+static FILEHANDLE CreateLockFile(const char * restrict fname ONLY_FOR_LOCK)
 // create lock file; works only if USE_LOCK is enabled
 {
 #ifdef USE_LOCK
@@ -1475,7 +1479,7 @@ static FILEHANDLE CreateLockFile(const char * restrict fname)
 
 //============================================================
 
-static void RemoveLockFile(FILEHANDLE fd,const char * restrict fname)
+static void RemoveLockFile(FILEHANDLE fd ONLY_FOR_LOCK,const char * restrict fname ONLY_FOR_LOCK)
 // closes and remove lock file; works only if USE_LOCK is enabled
 {
 #ifdef USE_LOCK
diff --git a/src/seq/Makefile b/src/seq/Makefile
index 3717de5f..648c8daf 100644
--- a/src/seq/Makefile
+++ b/src/seq/Makefile
@@ -34,19 +34,22 @@ $(PROGSEQ): $(COBJECTS) $(FOBJECTS)
 	@echo "Building $@"
 	$(CC) -o $@ $(LDFLAGS) $(COBJECTS) $(FOBJECTS) $(LDLIBS)
 
-# Everything is recompiled when any of makefiles is changed
-$(COBJECTS): %.o: %.c %.d $(MFILES)
+$(COBJECTS): %.o: %.c %.d
 	$(CC) -c $(CFLAGS) $(CDEFS) $<
 
 $(FOBJECTS): %.o: %.f $(MFILES)
 	$(CF) -c $(FFLAGS) $<
 
 # Dependencies are only generated for C sources; we assume that each Fortran file is completely 
-# independent or all of them are compiled at once
+# independent or all of them are compiled at once. 
+# Everything is recompiled when any of makefiles or .lastopts is changed
 
-$(CDEPEND): %.d: %.c $(MFILES)
+$(CDEPEND): %.d: %.c $(MFILES) $(LASTOPTSFILE)
 	$(CC) $(DEPFLAG) $(CFLAGS) $(CDEFS) $< $(DFFLAG) $@.$$$$; \
 	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
 	rm -f $@.$$$$
 
+$(LASTOPTSFILE):
+	echo LASTOPTS = $(OPTIONS) > $@
+
 -include $(CDEPEND)