# Solving

A sequence of calculation cycles is most often performed via the model solve command.[1] This command allows for cycling to continue until one or more solve limits are met. The model cycle can also be specified to simply perform a specified number of cycles.

Either of these commands must be issued from one of two places in the program: in the i Console pane, or from within a data file.

cs: ok, this spot right here would be a great place to say, hey, check out TOPIC to get all the lowdown on cycling/solving (which I think should be something called “solution” right under the “cycling” topic in “underpinnings”)

Start Cycling

To start cycling:

During Cycling

During model cycling, non-command processing operations are available (plotting, data file editing, work with certain tools, etc.). Issuing commands in the Console or performing command-issuing operations (for instance, building an extrusion in FLAC3D’s Extrusion pane) cannot be performed.

While cycling, the program will emit information about program status and results of cycling in three specific locations:

• the Console pane, which echoes input commands and shows output from commands as they are processed
• the i Cycling dialog, and
• (if needed) the warnings dialog.

The i Cycling dialog is always present when cycling; the warnings dialog is shown as the occasion for doing so arises (that is, when an error or warning has been issued during command processing). Both are described in separate topics.

Stop Cycling

To stop cycling:

• press the stop button ( ) on the toolbar. During cycling, this button is available on the toolbar of every pane in the program.
• press the button in the i Cycling dialog.
• press Shift + Esc key once to request a halt to cycling at the end of the current cycle (this allows model state data to be saved as needed once cycling halts), or
• press the Shift + Esc key twice to halt cycling immediately — which will cause loss of data from the current cycle.

Endnotes

 [1] The terms “solving” and “cycling” are only semi-interchangeable, due to the differences in the commands that use these words — model solve and model cycle. “Solving” always implies cycling to a predetermined termination point (a solve limit). “Cycling” is more abstract. It either proceeds some given number of steps or endlessly, if no number is supplied with the command. Thus, cycling is more closely synonymous with “stepping” (see Timestep). As a result, though solving is usually more focal in the modeling process, the term cycling will be encountered more often in this documentation when referring generally to iteration through the timestep.