yade-users team mailing list archive

[Rohit John <question685903@xxxxxxxxxxxxxxxxxxxxx>]

New question #685903 on Yade:
https://answers.launchpad.net/yade/+question/685903

Hello,

I am using Yade 2018.02b on a Virtual Box machine running Ubuntu 18.04.3 LTS. The host machine runs Windows 10.  

I was trying to learn how to plot using the first tutorial given in the YADE tutorial page. (The one with a ball bouncing on another ball). I followed the commands given about plotting in the section Data mining. It works for a sometime then gives an error. 

There was a post with a similar error. It recommended increasing iterPeriod in PyRunner by a few orders of magnitude. All it did was delay when the error occured
The code is given below


# basic simulation showing sphere falling ball gravity,
# bouncing against another sphere representing the support

# DATA COMPONENTS

# add 2 particles to the simulation
# they the default material (utils.defaultMat)
O.bodies.append([
	# fixed: particle's position in space will not change (support)
	sphere(center=(0,0,0),radius=.5,fixed=True),
	# this particles is free, subject to dynamics
	sphere((0,0,2),.5)
])

# FUNCTIONAL COMPONENTS

# simulation loop -- see presentation for the explanation
O.engines=[
	ForceResetter(),
	InsertionSortCollider([Bo1_Sphere_Aabb()]),
	InteractionLoop(
		[Ig2_Sphere_Sphere_ScGeom()],        # collision geometry
		[Ip2_FrictMat_FrictMat_FrictPhys()], # collision "physics"
		[Law2_ScGeom_FrictPhys_CundallStrack()]   # contact law -- apply forces
	),
	# Apply gravity force to particles. damping: numerical dissipation of energy.
	NewtonIntegrator(gravity=(0,0,-9.81),damping=0.1)
]

# set timestep to a fraction of the critical timestep
# the fraction is very small, so that the simulation is not too fast
# and the motion can be observed
O.dt=.5e-4*PWaveTimeStep()

# save the simulation, so that it can be reloaded later, for experimentation
O.saveTmp()

from yade import plot
plot.plots={'t':('coordNum','unForce',None,'Ek')}                # kinetic energy will have legend on the right as indicated by None separator.

O.trackEnergy=True
def addPlotData():
        # this function adds current values to the history of data, under the names specified
        plot.addData(t=O.time,Ek=utils.kineticEnergy(),coordNum=utils.avgNumInteractions(),unForce=utils.unbalancedForce())

O.engines+=[PyRunner(command='addPlotData()',iterPeriod=2000)]

plot.plots={'t':('coordNum','unForce',None,'Ek')}
plot.plot()

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
***********************************************************************************************************************

The error that I get is  given below

Unhandled exception in thread started by <function liveUpdate at 0x7f45b3db18c0>
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
/usr/lib/x86_64-linux-gnu/yade/py/yade/plot.py in liveUpdate(timestamp)
    506                         for ax in axes:
    507                                 try:
--> 508                                         ax.relim() # recompute axes limits
    509                                         ax.autoscale_view()
    510                                 except RuntimeError: pass # happens if data are being updated and have not the same dimension at the very moment

/usr/lib/python2.7/dist-packages/matplotlib/axes/_base.pyc in relim(self, visible_only)
   1936         for line in self.lines:
   1937             if not visible_only or line.get_visible():
-> 1938                 self._update_line_limits(line)
   1939 
   1940         for p in self.patches:

/usr/lib/python2.7/dist-packages/matplotlib/axes/_base.pyc in _update_line_limits(self, line)
   1799         Figures out the data limit of the given line, updating self.dataLim.
   1800         """
-> 1801         path = line.get_path()
   1802         if path.vertices.size == 0:
   1803             return

/usr/lib/python2.7/dist-packages/matplotlib/lines.pyc in get_path(self)
    955         """
    956         if self._invalidy or self._invalidx:
--> 957             self.recache()
    958         return self._path
    959 

/usr/lib/python2.7/dist-packages/matplotlib/lines.pyc in recache(self, always)
    665             y = self._y
    666 
--> 667         self._xy = np.column_stack(np.broadcast_arrays(x, y)).astype(float)
    668         self._x, self._y = self._xy.T  # views
    669 

/home/intern/.local/lib/python2.7/site-packages/numpy/lib/stride_tricks.pyc in broadcast_arrays(*args, **kwargs)
    257     args = [np.array(_m, copy=False, subok=subok) for _m in args]
    258 
--> 259     shape = _broadcast_shape(*args)
    260 
    261     if all(array.shape == shape for array in args):

/home/intern/.local/lib/python2.7/site-packages/numpy/lib/stride_tricks.pyc in _broadcast_shape(*args)
    191     # use the old-iterator because np.nditer does not handle size 0 arrays
    192     # consistently
--> 193     b = np.broadcast(*args[:32])
    194     # unfortunately, it cannot handle 32 or more arguments directly
    195     for pos in range(32, len(args), 31):

ValueError: shape mismatch: objects cannot be broadcast to a single shape



-- 
You received this question notification because your team yade-users is
an answer contact for Yade.