Initial conditions

The initial conditions block sets the initial displacement and velocity fields. It groups conditions by type, each mapping to a list of entries. The two types are displacement and velocity:

initial conditions:
  displacement:
    - node set: nsall
      component: y
      function: "0.393701 * x * x"
  velocity:
    - node set: nsall
      component: z
      function: "10.0"

Each entry uses the same fields:

Key	Required	Meaning
`node set`	yes	node set to initialize
`component`	yes	`x`, `y`, or `z`
`function`	yes	function expression in `t, x, y, z`

For a displacement entry, the function gives the initial displacement; the initial velocity is taken from its time derivative when that is nonzero (see Function expressions). For a velocity entry, the function sets the velocity directly.

The block is optional. It cannot be combined with a restart (the restart snapshot already carries the initial state). Conflicting velocity assignments to the same node and component are rejected.

Canonical examples

Initial displacement profile: examples/single/static-solid, examples/single/implicit-dynamic-solid