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The Twitter FEniCS bot

Visit the Twitter FEniCs bot

With FEniCs bot you can tweet your PDEs problems @fenicsbot and you will receive the solution, obtained with FEniCS, displayed as an answer!

Examples

Poisson equation

@fenicsbot Solve Poisson with domain=UnitSquare and f=pi*cos(pi*x[0])*cos(pi*x[1])

@fenicsbot Solve Poisson with domain=UnitSquare and f=0 and bdy0=1 and bdy1=1

Stokes equations

@fenicsbot Solve Stokes with domain=UnitSquare and f=pi*cos(pi*x[0])*cos(pi*x[1]),10

LinearElasticity

@fenicsbot Solve LinearElasticity with domain=Dolfin and f=sin(pi*x[0]),cos(pi*x[1])

Tweet Syntax

@fenicsbot Solve _Problem_ with par1=_par1val_ and par2=_par2val_ and ...

The valid options are problem specific.

Valid inputs:

_Problem_:

  1. Poisson, options: f: external force, domain: domain, bdyK: Dirichlet BC on piece K of the boundary, tolerance: the accuracy tolerance for $\int_\Omega u \textrm{d}x$, using automatic adaptivity
  2. Stokes, options: f: external force, domain: domain, bdyK: Dirichlet BC on piece K of the boundary
  3. LinearElasticity: f: external force, domain: domain, E: Youngs modulus, nu: Poissons ratio, bdyK: Dirichlet BC on piece K of the boundary
  4. Burgers: f: external force, domain: domain, ic: initial condition, dt: timestep, T: final time, nu: viscosity, bdyK: Dirichlet BC on piece K of the boundary

_Domain_:

  1. UnitInterval bdy0 is the point x[0]=0, bdy1 is the point x[0]=1
  2. UnitSquare bdy0 is the line x[0]=0, bdy1 is the line x[0]=1, bdy2 is the line x[1]=0, bdy3 is the line x[1]=1
  3. UnitCube bdy0 is the plane x[0]=0, bdy1 is the plane x[0]=1, bdy2 is the plane x[1]=0, bdy3 is the plane x[1]=1, bdy4 is the plane x[2]=0, bdy5 is the plane x[2]=1
  4. Dolfin bdy0 is the line x[0]=0, bdy1 is the line x[0]=1, bdy2 is the line x[1]=0, bdy3 is the line x[1]=1, bdy4 is the interior "Dolfin border"
  5. Circle bdy0 is the entire boundary.
  6. L bdy0 is the entire boundary.

_ExternalForce_: For Poisson you need to pass a forcing scalar, such as:

  1. Expression: f=pi*cos(pi*x[0])*cos(pi*x[1])
  2. Constant: f=0.0

For Stokes and LinearElasticity you need to pass a forcing vector, such as:

  1. Expression: f=cos(pi*x[0]),sin(pi*x[1])
  2. Constant: f=0,1

_BCs_: For solvers including bdy0, bdy1, ... as options, you can impose Dirichlet boundary conditions on reasonable pieces of the boundary. In order to impose the condition u=g on piece number 2 of the boundary, pass the option bdy2=g. All BCs not given default to 0.

Made by Karl Erik Holter, Eleonora Piersanti and Simon Funke at the BioComp Simula Hackathon 2015 at Finse, Norway.