datamax | For use with Datamax label printers | 3D Printing library

There are a few things going on:

• Some solvers don't like the spherical mesh, probably because of the enormous range in cell volumes. The SciPy LinearLUSolver seems to work. Judicious preconditioning might help other solvers.
• Eq. (45) in the paper you linked below defines the flux, but you are constraining the gradient. You need to divide by the diffusivity.
• X_ca is in units of [stoichiometry], but BoundaryR1_ca is in units of mol/(m**2 * s) (or mol/m**4 after dividing by D_ca. You need to divide by C_ca_max to get [stoichiometry]/m, as you're solving something halfway between Eq. (43) and Eq. (52).
• No-flux is the natural boundary condition for FiPy, so there's no need to constrain at mesh.facesLeft.
• The gradient at mesh.facesRight should be constrained to a vector (even in 1D).

With the changes below, I get behavior that looks consistent with Fig. 7 in Mayur et al..

tl;dr: You're probably seeing a difference in the behavior of the Matplotlib viewer and not in the solver.

• When I adjust for bugs and regressions with Matplotlib, I see very similar evolution with Py27 and Py3k. Until we get that fixed, you can see if these changes help:

By default the text is converted to and SVG elements, to use different tags such as enable the useHTML option:

Try to use this solution with the load instead the render. Doing update in the render callback creates the infinity loop. Code:

• These equations are ODEs, not PDEs. FiPy may be able to solve them, but there are other tools much better optimized for solving ODEs, such as SciPy's odeint and scikits.odes.
• I am not sure exactly what you mean by "It is not giving any pattern but just different monochromatic square(s) over a period of time." The random initial condition does not appear to evolve, but if I increase dt to 1.0, then V evolves to a uniform value of about 0.5. U does not appear to evolve for me, but that's a display glitch of some kind. V evolves to 0.598 and U evolves to 0.179. There is no pattern in space (if that's what you were expecting) because these equations have no spatial dependence; they only have partial derivatives in time, so there is absolutely nothing to cause the variables to flux from one cell to another.
• You appear to get away with it here, but your variables should always be defined on the same mesh, rather than u_mesh for U and v_mesh for V.
• No-flux boundary conditions are the default in FiPy, so there's no reason to specify U.faceGrad.constrain, etc.
  • Furthermore, there are no fluxes in these equations (because they're ODEs), so setting boundary fluxes isn't meaningful.
• Normally I would recommend making your equations more implicit, coupling them together, and sweeping, but none of this seems to have much effect on their evolution in this case.

You can have two approachs to achieve your goal. Install the library or add manually the js files.

You must use break; at the end of each case.(if you want to run only that particular case). What's happening in your code is whatever the toggle value is; case 2 will always run and overwrite the values of case0/case1.

To add a title: just add some text to your draw loop.