Misc

Misc

Simulator defaults

Starting a new simulation

Starting a new simulation will start a Gray–Scott simulation with two variables, $u$ and $v$.

Changing the default variable names

When changing Equations ($f(x)$) → Equations → Variables → Number to a higher number than the previously provided variable names cover, any additional variables will be named by default to VARIABLE2, VARIABLE3, …, VARIABLE8 (whichever position they fall in), regardless of how many variables there are in total.

You are advised to rename them to $v$, $w$, $q$ (for up to 4 variables) for simplicity, as other quantities are labelled according to these default names, e.g. $D_{VARIABLE2}$ corresponds to $D_v$ and so on. Variables beyond the fourth have no natural single-letter name; a common convention is u5 through u8, though any valid name works.

Default timestepping

By default, VisualPDE uses the forward Euler method with $\Delta t = 0.1$, which is likely to be too big for many problems. We recommend reducing the timestep and/or changing the timestepping scheme in this case.

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