Numerics Lab

New Users

When you ask DAE Solver to create a new document, it offers a few problem prototypes for you to choose from, as shown in the window below. Choose the one that is closest to the problem you would like to solve. You will be allowed to make as many changes as you want to these prototypes so choosing one of them does not constrain DAE Solver in any way. None is also a good way to get things started.

Example

Assume for example that you are trying to solve the system of three differential equations:

  1. dCa/dt = -Ca
  2. dCb/dt = Ca - Cb
  3. dCc/dt = Cb

with initial conditions:

  1. Ca = 1
  2. Cb = 0
  3. Cc = 0
Once this problem has been typed, it can be solved by clicking on the toolbar button named Solve. The problem also requires a domain to be specified for t, the independent variable, as shown below:

The additional numerical settings are hidden by default. We show them here to remind you that the independent variable domain is just one of many inputs you are allowed to change. Once you click the OK button, the solution will be displayed graphically. The curves in this graph are all black by default but can be easily colored, as illustrated below:

Problem Syntax

The syntax used by DAE Solver is similar to the syntax used by most programming languages and spreadsheet applications. The available operators are:

Parentheses are allowed:

Functions are available too:

Please be aware that functions abs, mod, ceil, and floor introduce discontinuities that could be problematic for the algorithms used to solve equation systems.