C+
C NAME:
C	IPSFuncQ
C CALLING SEQUENCE:
	real function IPSFuncQ(q)
C COMMON BLOCKS:
	common	/FQIPS/	hachodz,thetadz
!$omp threadprivate(/FQIPS/)
C INCLUDE:
	include		'math.h'
C MODIFICATION HISTORY:
C-
	    real	q

	if (q .eq. 0.0) then

	    IPSFuncQ = 0.0

	else

	    pi2 = 2.0*MATH__PI

	    a = q*q*hachodz/(2.0*pi2)	! Effect of fresnel filtering
	    do while (a .ge. 0.7)
		a = a-pi2*1000.0  !1.e+3
	    end do
	    a = sin(a)
	    fresnel = a*a

	    a = q*thetadz		! Effect of source size
	    a = a*a*0.5
	    sizeq = 0.0
	    if (a .lt. 10.0) sizeq = exp(-a)

	    a = 3.0			! JGR paper says: a=3.3
	    spectr = 1.0/(q**a)		! Effect of spectrum fluctuation 

	    IPSFuncQ = q*fresnel*sizeq*spectr

	end if

	return
	end