Fixed bug that caused a failure to braket the SFD slope when it is ne…

…gative

src/fraggle/fraggle_util.f90

@@ -81,6 +81,7 @@ module subroutine fraggle_util_set_mass_dist(self, param)
       !! Sets the mass of fragments based on the mass distribution returned by the regime calculation.
       !! This subroutine must be run after the the setup routine has been run on the fragments
       !!
+      use, intrinsic :: ieee_exceptions
       implicit none
       ! Arguments
       class(collision_fraggle),   intent(inout) :: self  !! Fraggle collision system object
@@ -101,6 +102,10 @@ module subroutine fraggle_util_set_mass_dist(self, param)
       integer(I4B), dimension(:), allocatable :: ind
       integer(I4B), parameter :: MAXLOOP = 20
       logical :: flipper
+      logical, dimension(size(IEEE_ALL))      :: fpe_halting_modes
+
+      call ieee_get_halting_mode(IEEE_ALL,fpe_halting_modes)  ! Save the current halting modes so we can turn them off temporarily
+      call ieee_set_halting_mode(IEEE_ALL,.false.)
 
       associate(impactors => self%impactors, min_mfrag => self%min_mfrag)
          ! Get mass weighted mean of Ip and density
@@ -146,6 +151,7 @@ module subroutine fraggle_util_set_mass_dist(self, param)
                fragments%density(1) = impactors%mass_dist(1) / volume(jtarg)
                if (param%lrotation) fragments%Ip(:, 1) = impactors%Ip(:,1)
             end associate
+            call ieee_set_halting_mode(IEEE_ALL,fpe_halting_modes)
             return
          case default
             write(*,*) "fraggle_util_set_mass_dist_fragments error: Unrecognized regime code",impactors%regime
@@ -176,8 +182,8 @@ module subroutine fraggle_util_set_mass_dist(self, param)
                   y1 = y1 - (i-1)**(-x1/3.0_DP)
                end do
                if (y0*y1 < 0.0_DP) exit
-               x1 = x1 * 1.6_DP
-               x0 = x0 / 1.6_DP
+               x1 = x1 * 1.1_DP
+               x0 = x0 * 1.1_DP
             end do
 
             ! Find the mass scaling factor with bisection
@@ -276,6 +282,7 @@ module subroutine fraggle_util_set_mass_dist(self, param)
 
       end associate
 
+      call ieee_set_halting_mode(IEEE_ALL,fpe_halting_modes)
       return
    end subroutine fraggle_util_set_mass_dist