nimsundials

Nim wrapper for Sundials

WORK IN PROGRESS

If you have a 64-bit Windows machine, you should be able to run it without any modifications (you may need to use Nim with MinGW compiler). If you have Linux or Mac you have to compile Sundials yourself and copy the lib/ folder in the installation dir and replace the one I have.

Progress

• NVector - partial support
• CVode - basic example works, most is not implemented yet.
• The rest - Not Implemented

How to define a ODE

You define a ODE of the form y' = f(t, y) with the CVodeProc template:

CVodeProc f:
  ydot = 0.1 * y

CVodeProc f2:
  ydot[0] = y[0] + 2 * y[1]
  ydot[1] = -0.5 * y[0] - 5.4 * y[1]

ydot is the result variable that you should assign y' to. ydot, y, t are implicitly defined. ydot and y are NVectorType and t is realtype. Do not use result.

How to solve an ODE

To solve a ODE you need:

• t0 - start time
• y0 - initial conditions
• f - the ODE function
• tout - the time you want to solve for.

To solve the ODE call CVodeSolve:

var t0 = 0.0
var y0 = newNVector([1.0, 2.0, 3.0])
var tout = 2.0
var reltol = 1e-5
var abstol = 1e-5
CVodeProc f:
  ydot = 2.0 * y # y' = 2y
var yout = CVodeSolve(f, y0, t0, tout, abstol, reltol)

Contributions

are happily welcomed :-)