Extract 2D cross-sections from the 3D sphere pack.

Hi All,

I modified the GravityDeposition.py from the examples for my case. Particularly, the 'checkUnbalanced()' function and here is how it looks:

def checkUnbalanced():
   if unbalancedForce() < .1:
      sp.toSimulation() # Add small sphere pack to the simulation until there are at least 100 bodies.
      O.run();
      if (len(O.bodies) > 100):# and (unbalancedForce() < .1): #O.bodies.numberOfGrains() > 5000
       O.run();
       if unbalancedForce() < .1:
        O.pause()
        #plot.saveDataTxt('bbb.txt.bz2')
        ### Write cross-sections to image files. ###
  X,Y,Z = np.meshgrid(np.arange(int(2*cylRad)),np.arange(int(2*cylRad)),np.arange(int(cylHt)),sparse=True,copy=False);
  F = np.zeros(X.shape);
  print len(O.bodies)
  for i in range(len(O.bodies)):
   b = O.bodies[i]
   if isinstance(b.shape,Sphere):
    a = b.state.pos
    idx = (np.sqrt((X - a[0])**2 + (Y - a[1])**2 + (Z - a[2])**2) <= b.shape.radius[i]).nonzero()
    F[idx] = 128;
  Xres = np.arange(int(4*cylRad)); Yres = np.arange(int(4*cylRad)); Zres = np.arange(int(2*cylHt));
  from scipy.interpolate import griddata
  I = griddata([X,Y,Z],F,[Xres,Yres,Zres],method='cubic');

In the above code, I have difficulty (or am getting errors) reproducing the assignment of F and the correct way to pass arguments to 'griddata' function. Could anyone please point out the correct way to do it?

** Following are the error messages**

Corresponding to assignment of 'idx' in my Python code, I get following error:

    --> 132 idx = (np.sqrt((X - spherePos[i,0])**2 + (Y - spherePos[i,1])**2 + (Z - spherePos[i,2])**2) <= sphereRad[i]).nonzero()
        133 F[idx] = 128;
        134 Xres = np.arange(int(4*cylRad)); Yres = np.arange(int(4*cylRad)); Zres = np.arange(int(2*cylHt));

    TypeError: 'float' object has no attribute '__getitem__'

If I comment the lines involving assignment of 'idx' and 'F' in my Python code, I get following error:

    /usr/lib/python2.7/dist-packages/scipy/interpolate/ndgriddata.pyc in griddata(points, values, xi, method, fill_value)
    177 xi, = xi
    178 # Sort points/values together, necessary as input for interp1d
    --> 179 idx = np.argsort(points)
        180 points = points[idx]
        181 values = values[idx]

    /usr/lib/python2.7/dist-packages/numpy/core/fromnumeric.pyc in argsort(a, axis, kind, order)
        873 except AttributeError:
        874 return _wrapit(a, 'argsort', axis, kind, order)
    --> 875 return argsort(axis, kind, order)
        876
        877

    ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()