Initial condition records

These records describe the initial conditions. They are counted by nic in the Components size record, and the numbering must start at one and end at n, where n is the number of records.

An initial condition works in one of three mutually exclusive modes, selected by which of conditions, f and field is present — tested in that order. Giving none of them is an error.

Expression mode

The preferred form. The initial value, velocity and acceleration are given as expressions, which may depend on position through the variables x, y and z, the coordinates of the node.

Record syntax

InitialCondition num (in) f (expr) set (in) dofs (ia) [dfdt (expr)] [d2fdt2 (expr)] [valType (in)]

Parameters

f (expr)

Expression for the initial value of the unknown. Defaults to 0.0.

[dfdt (expr)]

Expression for the initial velocity, the first time derivative. Defaults to 0.0.

[d2fdt2 (expr)]

Expression for the initial acceleration, the second time derivative. Defaults to 0.0.

dofs (ia)

The individual DOFs the condition applies to, using the DofIDItem values listed under Dof manager records.

set (in)

The set of nodes the initial condition is applied to; see Set records.

[valType (in)]

Physical meaning of the value; see valType under Load and boundary condition records.

Field mode

Initialises the unknowns from an externally registered field, for example one exported by a preceding sub-problem of a staggered analysis; see Exporting fields to a subsequent analysis.

Record syntax

InitialCondition num (in) field (in) set (in) dofs (ia) [valType (in)]

Parameters

field (in)

Identifier of the field to read the initial values from, as a FieldType enumeration value; see src/core/field.h.

Dictionary mode (deprecated)

Warning

Retained only for compatibility with old input files. Use the expression mode instead.

Record syntax

InitialCondition num (in) conditions (dc) [valType (in)]

Parameters

conditions (dc)

Dictionary of initial values, listing keys followed by their values. The key v is the velocity and a the acceleration.

In this mode the condition is attached to dof managers through their ic array rather than through a set; see Dof manager records.