Makefile_fastmath

#----------------------------------------------------
# this is a utility to test the fast sqrt functions
# to see if they are faster than the native calls
# if so, then the appropriate pre-processor flags
# are added
#
.PHONY: .make_mathflags .make_nofastmath getmathflags checkmath
ifndef FASTSQRT
    FASTSQRT=${shell if [ -e .make_nofastmath ]; then echo no; fi}
endif

ifeq ($(FASTSQRT), no)
    OBJTESTMATH=
    FASTMATH=no
else
    OBJTESTMATH= random.o io.o fastmath.o mpi_utils.o test_fastmath.o getmathflags.o
    FASTMATH=${shell if [ -e .make_mathflags ]; then cat .make_mathflags; fi}
endif

.make_mathflags: checksys $(OBJTESTMATH)
     ifeq ($(FASTSQRT), no)
	@touch .make_mathflags
     else
	@if [ ! -e $@ ]; then \
	    $(FC) $(FFLAGS) -o $(BINDIR)/getmathflags $(OBJTESTMATH) || ${MAKE} fastmathlinkerr; \
	    $(BINDIR)/getmathflags > .make_mathflags; \
	fi
     endif

ifeq ($(FASTMATH), yes)
    SRCFASTMATH=fastmath.o
    TEST_FASTMATH=test_fastmath.f90
    FPPFLAGS+=-DFINVSQRT
else
    SRCFASTMATH=
    TEST_FASTMATH=
endif

fastmath.o: fastmath.f90
	$(FC) $(FFLAGS) -o $@ -c $< || ${MAKE} fastmathlinkerr
test_fastmath.o: test_fastmath.f90
	$(FC) $(FFLAGS) -o $@ -c $< || ${MAKE} fastmathlinkerr
getmathflags.o: getmathflags.f90
	$(FC) $(FFLAGS) -o $@ -c $< || ${MAKE} fastmathlinkerr

fastmathlinkerr:
	@echo "***********************************************************************"
	@echo "*** ERROR linking fastsqrt stuff (requires Fortran->C call)         ***"
	@echo "*** Type make again to ignore this and compile without it           ***"
	@echo "***********************************************************************"
	@touch .make_mathflags
	@touch .make_nofastmath
	${MAKE} err;