# TIME_HISTORY_OUTPUT

Specify nodal solution output for a set of prescribed points.

AcuSolve Command

## Syntax

TIME_HISTORY_OUTPUT("name") {parameters...}

User-given name.

## Parameters

type (enumerated) [=nodal]
How the spatial location of the output points is specified.
nodal
Nodal points. Requires nodes.
coordinates
Coordinate points. Requires coordinates.
nodes (array) [no default]
List of nodes to be output. Used with nodal type.
coordinates or coord (array) [no default]
Four-column array consisting of a point identifier (integer) plus the xyz coordinate points to be output. Used with coordinates type.
output_frequency or out_freq (integer) >=0 [=1]
Time step frequency at which to output nodal solutions. If zero, this option is ignored.
output_time_interval or out_intv (integer) >=0 [=0]
Time frequency at which to output nodal solutions. If zero, this option is ignored.

## Description

This command specifies a list of points whose nodal solution fields are to be written into a results database. For example,
TIME_HISTORY_OUTPUT( "sample nodes" ) {
type                 = nodal
nodes                = { 1 ;13 ;26 ; }
output_frequency     = 10
output_time_interval = 2.5
}

specifies that the nodal solution values of nodes 1, 13, and 26 are to be output every 10 time steps, every 2.5 units of time, and at the last time step.

The nodes parameter is a single-column array containing a list of node numbers. Node numbers must be valid numbers, as given by the COORDINATE command. The nodal solution of these nodes is output at the frequency specified.

The nodal numbers may be read from a file. For the above example, the nodes may be placed in a file, such as sample.nod:
1
13
26
TIME_HISTORY_OUTPUT( "sample nodes" ) {
type                  = nodal
output_frequency      = 10
output_time_interval  = 2.5
}
Instead of outputting the nodal solution at particular nodes, the coordinates type may be used to interpolate the nodal solutions to the coordinate points given by coordinates. If there is mesh movement the reference coordinates are used, as opposed to the current coordinates. For example,
TIME_HISTORY_OUTPUT( "sample coordinates" ) {
type                  = coordinates
coordinates           = { 1, 1.1, 0.5, 7.8 ;
2, 1.5, 2.3, 4.6 ;
3, -3.2, 1.8, 5.4 ; }
output_frequency      = 10
output_time_interval  = 2.5
}
The coordinates parameter is a four-column array containing an identifying integer plus the xyz coordinates. This identifier is unrelated to the node numbers. For the above example, the coordinates may be placed in a file, such as sample.crd:
1 1.1 0.5 7.8
2 1.5 2.3 4.6
3 -3.2 1.8 5.4
TIME_HISTORY_OUTPUT( "sample coordinates" ) {
type                 = coordinates
output_frequency     = 10
output_time_interval = 2.5
}

Any point in coordinates that falls outside of the mesh is projected to the nearest point in the mesh.

Once the output to disk is complete, it can then be translated to other formats using the AcuTrans program and other post-processing modules; see the AcuSolve Programs Reference Manual for details.

If either output_frequency or output_time_interval is non-zero, the solution points will be output at the end of the run. If both are zero, no data are output.

Run times may not coincide with output_time_interval. In this case, the solution points are output every time step which passes through a multiple of output_time_interval.

The TIME_HISTORY_OUTPUT command is designed for outputting a select number of points at higher frequency levels than is practical with the NODAL_OUTPUT command. However, if the number of points in TIME_HISTORY_OUTPUT becomes large, the use of TIME_HISTORY_OUTPUT can become less efficient than the use of the NODAL_OUTPUT command.