diff --git a/GCC_default.mk b/GCC_default.mk
new file mode 100644
index 0000000..66e43cf
--- /dev/null
+++ b/GCC_default.mk
@@ -0,0 +1,198 @@
+# Basic Defintions for using GNU-compiler suite sequentially
+# requires setting of COMPILER=GCC_
+
+CC	= gcc
+CXX = g++
+F77	= gfortran
+LINKER  = ${CXX}
+
+WARNINGS = -Wall -pedantic -Wextra -Weffc++ -Woverloaded-virtual -Wfloat-equal -Wshadow \
+           -Wredundant-decls -fmax-errors=1
+#  -Wunreachable-code  -Winline
+CXXFLAGS += -ffast-math -O3 -march=native -std=c++17 ${WARNINGS}
+#CXXFLAGS += -Ofast -funroll-all-loops -std=c++17 ${WARNINGS}
+#-msse3
+# -ftree-vectorizer-verbose=2  -DNDEBUG
+# -ftree-vectorizer-verbose=5
+# -ftree-vectorize -fdump-tree-vect-blocks=foo.dump  -fdump-tree-pre=stderr
+
+# CFLAGS	= -ffast-math -O3 -DNDEBUG -msse3 -fopenmp -fdump-tree-vect-details
+# CFLAGS	= -ffast-math -O3 -funroll-loops -DNDEBUG -msse3 -fopenmp -ftree-vectorizer-verbose=2
+# #CFLAGS	= -ffast-math -O3 -DNDEBUG -msse3 -fopenmp
+# FFLAGS	= -ffast-math -O3 -DNDEBUG -msse3 -fopenmp
+# LFLAGS  = -ffast-math -O3 -DNDEBUG -msse3 -fopenmp
+LINKFLAGS   += -O3
+
+#architecture
+#CPU = -march=znver2
+CXXFLAGS  += ${CPU}
+LINKFLAGS += ${CPU}
+
+# different libraries in Ubuntu or manajaró
+ifndef UBUNTU
+UBUNTU=1
+endif
+
+# BLAS, LAPACK
+ifeq ($(UBUNTU),1)
+#LINKFLAGS += -llapack -lblas -llapacke
+CXXFLAGS  += -I/usr/include/x86_64-linux-gnu
+LINKFLAGS += -L/usr/lib/x86_64-linux-gnu -lopenblas -llapack -llapacke
+# -lopenblas
+else
+# on  archlinux
+LINKFLAGS += -llapack -lopenblas -lcblas
+endif
+
+# interprocedural optimization
+#CXXFLAGS  += -flto
+#LINKFLAGS += -flto
+
+# for debugging purpose (save code)
+# -fsanitize=leak         # only one out the three can be used
+# -fsanitize=address
+# -fsanitize=thread
+SANITARY =  -fsanitize=address  -fsanitize=undefined -fsanitize=null -fsanitize=return \
+ -fsanitize=bounds -fsanitize=alignment -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow \
+ -fsanitize=bool -fsanitize=enum -fsanitize=vptr
+#CXXFLAGS  += ${SANITARY}
+#LINKFLAGS += ${SANITARY}
+
+# profiling tools
+#CXXFLAGS  += -pg
+#LINKFLAGS += -pg
+
+
+default: ${PROGRAM}
+
+${PROGRAM}:	${OBJECTS}
+	$(LINKER)  $^  ${LINKFLAGS} -o $@
+
+clean:
+	@rm -f ${PROGRAM} ${OBJECTS}
+
+clean_all:: clean
+	-@rm -f *_ *~ *.bak *.log *.out *.tar *.orig *.optrpt
+	-@rm -rf html
+
+run: clean ${PROGRAM}
+#run: ${PROGRAM}
+#	time  ./${PROGRAM} ${PARAMS}
+	./${PROGRAM} ${PARAMS}
+
+# tar the current directory
+MY_DIR = `basename ${PWD}`
+tar: clean_all
+	@echo "Tar the directory: " ${MY_DIR}
+	@cd .. ;\
+	tar cf ${MY_DIR}.tar ${MY_DIR} *default.mk ;\
+	cd ${MY_DIR}
+# 	tar cf `basename ${PWD}`.tar *
+#find . -size +10M > large_files
+#--exclude-from ${MY_DIR}/large_files
+
+zip: clean
+	@echo "Zip the directory: " ${MY_DIR}
+	@cd .. ;\
+	zip -r ${MY_DIR}.zip ${MY_DIR} *default.mk ;\
+	cd ${MY_DIR}
+
+doc:
+	doxygen Doxyfile
+
+#########################################################################
+.SUFFIXES: .f90
+
+.cpp.o:
+	$(CXX) -c $(CXXFLAGS) -o $@ $<
+#	$(CXX) -c $(CXXFLAGS) -o $@ $<  2>&1 | tee -a $<.log 
+#	$(CXX) -c $(CXXFLAGS) -o $@ $<  2>&1 | tee -a $(<:.cpp=.log)
+
+.c.o:
+	$(CC) -c $(CFLAGS) -o $@ $<
+
+.f.o:
+	$(F77) -c $(FFLAGS) -o $@ $<
+
+.f90.o:
+	$(F77) -c $(FFLAGS) -o $@ $<
+
+##################################################################################################
+#    some tools
+# Cache behaviour (CXXFLAGS += -g  tracks down to source lines; no -pg in linkflags)
+cache: ${PROGRAM}
+	valgrind --tool=callgrind --simulate-cache=yes ./$^  ${PARAMS}
+#	kcachegrind callgrind.out.<pid> &
+	kcachegrind `ls -1tr  callgrind.out.* |tail -1`
+
+# Check for wrong memory accesses, memory leaks, ...
+# use smaller data sets
+# no "-pg"  in compile/link options
+mem: ${PROGRAM}
+	valgrind -v --leak-check=yes --tool=memcheck --undef-value-errors=yes --track-origins=yes --log-file=$^.addr.out --show-reachable=yes ./$^  ${PARAMS}
+# Graphical interface
+# valkyrie
+
+#  Simple run time profiling of your code
+CXXFLAGS += -g -pg
+LINKFLAGS += -pg
+prof: ${PROGRAM}
+	./$^  ${PARAMS}
+	gprof -b ./$^ > gp.out
+#	kprof -f gp.out -p gprof &
+
+#                   sudo apt install gprofng-gui
+#                   https://parallel.computer/presentations/PPoPP2023/2023-Ruud-Slides.pdf
+#   read §3 in      https://sourceware.org/binutils/docs/gprofng.html
+# /usr/bin/gp-collect-app -o test.1.er -p on -S on /home/ghaase/Lectures/Math2CPP/Codes/seq/jacobi_oo_stl/main.GCC_ 
+prof2: ${PROGRAM}
+	gprofng collect app -h auto ./$^  ${PARAMS}
+#	gprofng display text -functions `ls -1tdr test.*.er |tail -1`
+	gprofng display text -script gprofng_script2 `ls -1tdr test.*.er |tail -1`
+#	gprofng display text -script gprofng_script2 test.*.er
+#	gprofng display gui &
+	
+prof3: ${PROGRAM}
+	perf record ./$^  ${PARAMS}
+	perf report
+#  perf in Ubuntu 20.04:   https://www.howtoforge.com/how-to-install-perf-performance-analysis-tool-on-ubuntu-20-04/
+#  * install 
+#  * sudo vi /etc/sysctl.conf
+#                add   kernel.perf_event_paranoid = 0
+
+#Trace your heap:
+#> heaptrack ./main.GCC_
+#> heaptrack_gui heaptrack.main.GCC_.<pid>.gz
+heap: ${PROGRAM}
+	heaptrack ./$^  ${PARAMS}
+	heaptrack_gui  `ls -1tr  heaptrack.$^.* |tail -1` &
+
+codecheck: $(SOURCES)
+	cppcheck --enable=all --inconclusive --std=c++17 --suppress=missingIncludeSystem $^
+
+
+########################################################################
+#  get the detailed  status of all optimization flags
+info:
+	echo "detailed  status of all optimization flags"
+	$(CXX) --version
+	$(CXX) -Q $(CXXFLAGS) --help=optimizers
+	lscpu
+	inxi -C
+	lstopo
+
+# Excellent hardware info
+#	hardinfo
+# Life monitoring of CPU frequency etc.
+#	sudo i7z
+
+# Memory  consumption
+#	vmstat -at -SM 3
+#	xfce4-taskmanager
+
+
+# https://www.tecmint.com/check-linux-cpu-information/
+#https://www.tecmint.com/monitor-cpu-and-gpu-temperature-in-ubuntu/
+
+# Debugging:
+# https://wiki.archlinux.org/index.php/Debugging