Hello,

I’m teaching myself Julia to solve PDE. As toy problem I am duplication this very simple heat equation problem:

Dirichlet boundary conditions

I’m trying to redefine the initial condition from:

```
bcs = [u(0, x) ~ cos(x),
u(t, 0) ~ exp(-t),
u(t, 1) ~ exp(-t) * cos(1)]
```

to:

```
bcs = [u(0, x) ~ cos(π*x),
u(t, 0) ~ exp(-t),
u(t, 1) ~ exp(-t) * cos(1)]
```

The first initial condition is not giving me error, but when I use the 2nd initial condition, Julia is giving this error:

```
ERROR: type PeriodicBoundary has no field order
```

I did a some investigating and added 1 * before pi, as shown below.

```
bcs = [u(0, x) ~ cos(1*π*x),
u(t, 0) ~ exp(-t),
u(t, 1) ~ exp(-t) * cos(1)]
```

This approach somehow solved the problem. My question is why do I need the multiplier?