Start/Stop Generating

Starts or stops generating the current pattern. This item can also be used to stop a running script, but it's much easier to hit escape or click the tool bar's stop button.

Next Generation

Advances the pattern to the next generation. Note that you can hit control-space to advance only the current selection, or shift-space to advance everything outside the selection (in both cases the generation count will not change).

Next Step

Advances the pattern to the next step. The current step size is displayed in the status bar as a number of the form "b^e" where b is the base step and e is the exponent. The base step can be changed by the Set Base Step dialog (see below), and the exponent can be changed by the Faster/Slower items (see below).

Reset

Restores the starting pattern and generation count. It also resets the algorithm, rule, scale, location, step size, selection and layer name to the values they had at the starting generation. The starting generation is typically zero, but it can be larger after loading an RLE/macrocell file that stores a non-zero generation count.

Set Generation...

Opens a dialog to change the generation count. You can enter readable numbers like "1,234,567", or include a leading +/- sign to specify a number relative to the current generation count.

Faster

Increases the step exponent in the status bar by 1. This increases the speed by displaying fewer generations. The step exponent is reset to 0 when you create a new pattern, load a pattern file, or switch to a different algorithm.

Slower

Decreases the step exponent in the status bar by 1. This decreases the speed by displaying more generations. The step exponent is reset to 0 when you create a new pattern, load a pattern file, or switch to a different algorithm. If the exponent is 0 when you select this item then a small delay will occur between each generation. Further slowing will double the delay until a maximum value is reached. Use Preferences > Control to set the minimum and maximum delay times.

Set Base Step...

Opens a dialog to change the current base step, but only temporarily. Golly will restore the default base step (set in Preferences > Control) when you create a new pattern, load a pattern file, or switch to a different algorithm. The base step can be any number from 2 to 10,000 (but be aware that Golly's hashing algorithms are most efficient when the base step is a power of 2).

Auto Fit

If ticked then Golly will automatically fit a generating pattern inside the view if any part of the pattern moves out of view. This option is only used when doing many generations via Start or Next Step (that's why it's in the Control menu rather than the View menu), or when displaying patterns in a timeline (see Show Timeline).

Note that if you are generating a pattern and decide to change scale or do any sort of scrolling then the Auto Fit option is automatically turned off (the assumption being that you now want manual control over the scale and/or location).

TIP: If you find the Auto Fit option too confusing then leave it off and hit "f" to manually fit the pattern inside the view whenever you like.

Hyperspeed

If ticked, and the current algorithm uses hashing, then Golly will automatically increase the step exponent at regular intervals (every 64 steps). Hyperspeed mode is a convenient way to run a complex pattern as far as possible. (For very chaotic patterns, using QuickLife may actually run it further.) For highly regular patterns, hyperspeed mode quickly "runs away", generating exponentially fast.

Show Hash Info

Tick this option to turn on status messages that inform you when a hashing algorithm is doing garbage collection, resizing its internal hash table, or changing the step size (which can involve walking the entire hash). The garbage collection messages say which garbage collection it is overall, and if it is a subsequent garbage collection for the same step (the count will be in parentheses), and the percentage of memory reclaimed.

Interpreting these numbers is more an art than a science because some patterns exhibit odd behavior, but in general, if a garbage collection is reclaiming less than 70% of the total memory, or more than ten garbage collections occur for a single step, you can be fairly certain that the algorithm is effectively stalled and further progress will be extremely slow. Reducing the step size may help, but it may need to be reduced substantially in order to have an impact. Increasing the maximum memory that the algorithm can use may also help.

Start/Stop Recording

This item lets you start recording a new timeline (if none exists), or extend an existing timeline (always from its final frame). Golly will proceed to generate and save (in memory) a sequence of patterns separated by the current step size.

If a timeline is being recorded then this item will stop the recording. Note that it's probably easier to click on the start/stop button in the timeline bar (use Show Timeline in the View menu to show/hide this bar). Recording will also stop if you hit the escape key, or if the maximum number of frames is reached (32,000).

A lot of Golly's functionality is disabled while a timeline exists (which includes when it's being recorded). For example, you can't do any editing or generating, nor can you change the current algorithm, rule or step size. You can however do the usual zooming and panning, and you can add/delete/switch layers (each non-cloned layer has its own separate timeline). You can also make selections, but only the last selection is remembered when the timeline is deleted.

Delete Timeline

Deletes the existing timeline. The currently displayed frame becomes the current generation (any later frames are lost), but Golly saves the first frame of the timeline so you can Reset/Undo back to that generation.

Set Algorithm

This submenu lets you switch algorithms. Note that changing the current algorithm can change the current rule. If the new algorithm doesn't support the current rule then Golly will switch to the new algorithm's default rule. If a pattern exists then some cell states might have to be modified if the new universe has fewer states than the old universe.

Golly assigns a different status bar color to each algorithm to give you some feedback about which algorithm is currently in use. You can use Preferences > Color to change these colors.

Most of Golly's algorithms (all except QuickLife) use a hashing technique to generate patterns. This method performs brilliantly on patterns that have a lot of regularity in time or space. Conversely, it can perform very poorly on chaotic patterns. A hashing algorithm may initially appear to be slow, but as the hash table fills up with knowledge about the pattern, it will run faster and faster, so be patient.

Use Preferences > Control to set the maximum amount of hash memory for each algorithm. The initial setting is 500MB. The higher you set the memory limit, the larger patterns you can run and the farther and faster you can run them. However, setting this limit high also increases the amount of time required to change the step size (both manually and in hyperspeed mode) and increases the length of the garbage collection pauses. Nonetheless, it is generally best to set this quite high — typically 80% of the amount of physical memory in your computer. Setting this number high enough often makes more than a difference of 1000 in performance. How high is high enough depends greatly on the pattern and the step size, however, in unpredictable ways.

Set Rule...

Opens a dialog to change the current rule (which is displayed inside square brackets in the main window's title bar). The dialog also allows you to change the current algorithm — if the current rule is not valid in the new algorithm then the algorithm's default rule will be used.

A help button can be used to expand the dialog and display information about the current algorithm along with examples of the rules it supports. If you click on one of the special rule links then the rule string is automatically pasted into the new rule box. Another way to enter a new rule is to choose one from the list of named rules. You can add your own names to this list.

By default, all algorithms create an unbounded universe, but it's also possible to create a bounded universe by adding a special suffix to the usual rule. See here for details.