In SuperMemo, subsets are sets of elements. Subsets are usually viewed in the browser. Subsets are processed with subset operations. Subsets can be stored in subset files for later use. The default extension of subset files is sub. Each element in a subset file is stored as a four-byte element number. This way, subset file size in bytes is four times the number of elements in the subset. The same subset files can be used by different collections, but such use is meaningful only if the collections have the same numbering of elements (e.g. if these are copies of the same collection).
Choosing a subset
To select a subset and open it in the browser, you may use many options that are too numerous to list. Here are only a few frequently used examples:
- Search : Find elements (Ctrl+F) - to collect elements containing the same text (e.g. "Eisenhower")
- View : Outstanding - to inspect all outstanding elements
- View : Branch in the contents window - to inspect elements belonging to a single branch
- View : Filter - to inspect all elements that fall into a selected range of priority, interval, repetition date, difficulty, etc.
- View : Subset - to open a given subset file in the browser
- Child options on the browser menu - to create a sub-browser with all memorized, pending, dismissed or selected elements from the current browser
- Subset operations in registries with View : Browse current, View : Browse selected, and View : Browse all - to create browsers with elements using a given subset of registry members
Creating subset files
To create a subset file use one of the following options:
- Subset : Save all on the browser menu saves the contents of the browser in a subset file (e.g. this option used on the browser opened with View : Memorized will create a subset with all memorized elements)
- Select : Save selection on the browser menu saves all selected elements in the browser. Selections are made by clicking the leftmost browser column or with subset operations such as Select : Select browser range, etc.
- Export : Subset on the contents menu saves a contents branch in a subset file
Some subset files are created automatically for you. You can view them with View : Subset. For example: last_browser (subset with all elements displayed in the last opened browser), searched (subset with all elements found with the last Ctrl+F search), last_child (subset with elements extracted with the last Child operation in the browser), tasklist (subset will all tasks extracted with Tools : Open in browser on the tasklist manager menu), etc.
Subset can be processed using a nearly infinite combination of options and commands in SuperMemo. Here are only a few examples:
- Process browser : Learning : Learn (Ctrl+L) on the browser menu makes it possible to make repetitions on a subset of elements
- Process browser : Learning : Review all on the browser menu makes it possible to execute repetitions on the whole subset. Elements that are not outstanding will be subject to mid-interval repetition. Only dismissed elements will not be processed
- Process browser : Postpone on the browser menu postpones outstanding repetitions in a subset of elements
- Export : Transfer elements on the browser menu makes it possible to transfer the subset of element to another collection
- Export : XML on the browser menu makes it possible to export a subset of elements in the XML format (e.g. for using it with other SuperMemos such as SuperMemo for Pocket PC, etc.)
- Export : Q&A text file on the browser menu makes it possible to export a subset of elements as a text file of questions and answers
- Sort options on the browser menu help you review a subset of elements sorted by intervals, difficulty, memory lapses, etc.
- Subset : Match to subset on the registry menu displays all registry members that are in use by the elements of a given subset