CFLAGS = -Wall -pthread -Ofast -march=native

Out.error.png:Out.data.txt Makefile
	echo '\
	set term png ;\
	set out "$@" ;\
	set title "Monte Carlo calculation of $$\pi$$";\
	set logscale x ;\
	set logscale y ;\
	set xlabel "number of points $$N$$";\
	set ylabel "absolute error";\
	a=1 ;\
	f(x)=a/sqrt(x) ;\
	fit f(x) "$<" using 1:3 via a ;\
	plot [][1e-5:8e-3]\
	 "$<" using 1:3 with linespoints title "actual error"\
	,f(x) with lines title "$$1/\sqrt{N}$$"\
	'|pyxplot

ns = 1 1.5 2 4 8
Out.data.txt:main #Makefile
	>$@
	for n in $(ns); do ./$< "$$n"e5 >> $@; done
	for n in $(ns); do ./$< "$$n"e6 >> $@; done
	for n in $(ns); do ./$< "$$n"e7 >> $@; done

.PHONEY:clean
clean:
	$(RM) main Out* *.log