Hi, I am running a simulation on a mesh with large number of nodes. I need to capture the results at a subset of the nodes. I am running into trouble when I execute the job in parallel. Kindly take a look at the lines in red to understand the problem. While I am not getting an error, I am also not able to get the correct results here. I would appreciate your assistance in this regard. Thanks Abhishek ########################################### # Obtaining the solution for a subset of mesh nodes ########################################## x,y,z = SpatialCoordinate(W.mesh()) phi=ufl.mathfunctions.Atan2(y,x) Nsteps=int(T/deltat) time=np.linspace(0,T,Nsteps+1) resnodesx,rescoords=axialslice(mesh,Ro,np.pi/2) # axialslice returns a set of nodes and their coordinates corresponding to a particular criterion resnodes=resnodesx.astype(np.int32) #PETSc gives an error if the indices are not int32 # Trying to save the solution components at all time instants for a particular subset uradial=np.zeros((len(resnodes),len(time)+3)) utang=np.zeros((len(resnodes),len(time)+3)) uaxial=np.zeros((len(resnodes),len(time)+3)) uradial[:,:3]=rescoords utang[:,:3]=rescoords uaxial[:,:3]=rescoords for i in range(len(time)): t = time[i] collar_disp.assign([0.0,0.0,collar_load(t,T_pulse,f_c,amp=dispamp)]) solver1.solve() # Update old fields with new quantities u_nm1.assign(u_n) u_n.assign(u_np1) u_r.assign(interpolate(u_n[0]*cos(phi)+u_n[1]*sin(phi),W)) u_t.assign(interpolate(-u_n[0]*sin(phi)+u_n[1]*cos(phi),W)) u_z.assign(interpolate(u_n[2],W)) with u_r.dat.vec_ro as vur: #Obtained this idea from Printing in Parallel page of Firedrake Docs urad=vur.getValues(resnodes) print(len(urad)) # length of urad seems to differ for each process uradial[:,i+3]=urad with u_t.dat.vec_ro as vut: utan=vut.getValues(resnodes) utang[:,i+3]=utan with u_z.dat.vec_ro as vuz: uax=vuz.getValues(resnodes) uaxial[:,i+3]=uax if i%20 ==0: outfile.write(u_n,u_r,u_t,u_z, time=t) gc.collect() #Consequently the CSV's contain only a subset of the nodal results np.savetxt(csvradfilename,uradial,fmt='%1.6e',delimiter=',') np.savetxt(csvtangfilename,utang,fmt='%1.6e',delimiter=',') np.savetxt(csvaxialfilename,uaxial,fmt='%1.6e',delimiter=',') -- Abhishek Venketeswaran NETL Research Associate - ORISE National Energy Technology Laboratory Department of Energy abhishek.venketeswaran@netl.doe.gov Work: 412-386-4833 Mobile: 716-507-7890 www.netl.doe.gov<http://www.netl.doe.gov> [cid:fc8c5c43-be1a-42c1-880c-cb38951ae7af]