Merge pull request #10 from ipelupessy/fractalcluster_nsmax_fix

fix for nsmax problem 

closes #7 7

src/amuse/community/fractalcluster/interface.py

@@ -212,7 +212,7 @@ def clear_particle_set(self):
 class MakeFractalCluster(object):
 
     def __init__(self, N=None, convert_nbody=None, masses=None, do_scale=True,
-            random_seed=None, fractal_dimension=1.6, virial_ratio=0.5, verbose=False):
+            random_seed=None, fractal_dimension=1.6, virial_ratio=0.5, verbose=False, match_N=True):
         if masses is None:
             if N is None:
                 raise exceptions.AmuseException("Either keyword argument 'N' (number of particles) or "
@@ -231,6 +231,7 @@ def __init__(self, N=None, convert_nbody=None, masses=None, do_scale=True,
         self.fractal_dimension=fractal_dimension
         self.virial_ratio=virial_ratio
         self.verbose=verbose
+        self.match_N=match_N
 
     def new_model(self):
         generator = FractalCluster(redirection=("none" if self.verbose else "null"))
@@ -239,6 +240,9 @@ def new_model(self):
         if self.random_seed is not None:
             generator.parameters.random_seed = self.random_seed
         generator.generate_particles()
+        if self.match_N:
+            while len(generator.particles)<self.N:
+                generator.generate_particles()
         result = generator.particles.copy()
         generator.stop()
         result.mass = self.masses

src/amuse/community/fractalcluster/src/amuse_helpers.f90

@@ -30,8 +30,8 @@ function amuse_generator() result(err)
   endif  
   if(allocated(r)) deallocate(r,v)
   allocate(r(3,nstar),v(3,nstar))
-  call makefractal(nstar,r,v,fdim,iseed)
   n_generated = nstar
+  call makefractal(n_generated,r,v,fdim,iseed)
 end function
 
 end module

src/amuse/community/fractalcluster/src/makefractal.f90

@@ -235,17 +235,20 @@ SUBROUTINE makefractal(nstar,rstar,vstar,fdim,idum)
      IF (ndo==nsnow) EXIT
    END DO
    nsmax=ndo - 1
-   IF (nsmax<nstar) STOP 'nsmax<nstar - change random number seed'
+   IF (nsmax<nstar) THEN
+     WRITE(6,*) 'nsmax<nstar - change random number seed'
+     nstar=nsmax
+  ENDIF
 !
 ! we now have a fractal of nsmax stars
 ! need to randomly remove stars until we get nstar
    DO
 ! star to remove
+     IF (nsmax==nstar) EXIT
      is=INT(ran2(idum)*REAL(nsmax)) + 1
      r(1:3,is)=r(1:3,nsmax)
      v(1:3,is)=v(1:3,nsmax)
      nsmax=nsmax - 1
-     IF (nsmax==nstar) EXIT
    END DO
    WRITE(6,*) 'Cut to size', nsmax
 !