I managed to obtain an executable with -O2 set that does not produce segmentation faults with the following arch file:<br><br>INTEL_MKL = /opt/intel/Compiler/11.1/069/mkl<br>INTEL_INC = $(INTEL_MKL)/include<br>INTEL_INC_FFTW = $(INTEL_INC)/fftw<br>INTEL_LIB = $(INTEL_MKL)/lib/em64t<br>INTEL_FFTW_LIB = $(INTEL_MKL)/interfaces/fftw3xf<br>#LIBINT_LIB = /opt/lib/libint.intel11.x64/lib<br>LIBINT_LIB = /u/roger/build/libint1.1.4-ompi/lib<br>LIBINT_INC = /u/roger/build/libint1.1.4-ompi/include<br><br>CC       = cc<br>CPP      = cpp<br>FC       = mpif90<br>LD       = mpif90<br>AR       = xiar -r<br>DFLAGS   = -D__INTEL -D__FFTSG -D__parallel -D__BLACS -D__SCALAPACK -D__FFTW3 -D__FFTMKL -D__LIBINT -D__HAS_NO_ISO_C_BINDING<br>CPPFLAGS = -C -traditional $(DFLAGS) -I$(INTEL_INC) -I$(INTEL_INC_FFTW) -I/u/roger/temp -I$(LIBINT_INC)<br>FCFLAGS  = $(DFLAGS) -I$(INTEL_INC) -I/u/roger/temp -O2 -xW -heap-arrays 64 -funroll-loops -fpp -free <br>FCFLAGS2 = $(DFLAGS) -I$(INTEL_INC) -I/u/roger/temp -O1 -xW -heap-arrays 64 -fpp -free<br>#FCFLAGS  = $(DFLAGS) -I$(INTEL_INC) -I/u/roger/temp -O2 -xHost -heap-arrays 64 -fpp -free <br>LDFLAGS  = $(FCFLAGS) -I$(INTEL_INC) -I/u/roger/temp<br>LIBS     = -L$(INTEL_LIB) -L$(INTEL_FFTW_LIB) -lfftw3xf_intel -limf -lm -lmkl_scalapack_lp64 -lmkl_blacs_openmpi_lp64 \<br>           -lmkl_blacs_lp64 -lmkl_intel_lp64 -lmkl_sequential -lmkl_core \<br>           /u/roger/opt/r422e2/cp2k/tools/hfx_tools/libint_tools-mpi/libint_cpp_wrapper.o \<br>           $(LIBINT_LIB)/libderiv.a $(LIBINT_LIB)/libint.a -lstdc++ -lpthread <br><br>OBJECTS_ARCHITECTURE = machine_intel.o<br><br><br>graphcon.o: graphcon.F <br>        $(FC) -c $(FCFLAGS2) $<<br>