.. Athena document is copyright 2016 Bruce Ravel and released under The Creative Commons Attribution-ShareAlike License http://creativecommons.org/licenses/by-sa/3.0/ Frozen groups ============= There is a feature that :demeter:`athena` shares with almost any other computer program |nd| not just analysis programs, but any program. Soon after starting to use :demeter:`athena`, you will do something silly and regrettable. Often this is as simple as changing a parameter to some bad value and forgetting what the good value was. To help mitigate this sort of problem, :demeter:`athena` allows you to *freeze* data groups. A frozen group is one for which you cannot change its parameter values. When a group is frozen, the entry boxes associated with parameters become deactivated, which means that it is impossible to type in them. Furthermore, any global action, such as constraining parameters or using the alignment tool, will have no effect on the frozen group. The idea behind frozen groups is that, after working for a while to find parameter values that you like, you can freeze the group to avoid inadvertently altering its parameters. The various group freezing functions can be found in the :guilabel:`Freeze` menu, as shown in the screenshot below. .. _fig-freeze: .. figure:: ../../_images/ui_freeze.png :target: ../_images/ui_freeze.png :align: center Several visual cues indicate that a group is frozen, including the green highlighting the group list and the disabling of most controls. The frozen state of the current group can be toggled using the :guilabel:`Freeze` check button or by typing :button:`Alt`-:button:`f`. You can set the frozen state of multiple groups using the items in the :guilabel:`Freeze` menu. There you will find options for freezing or unfreezing all groups, all marked groups, or groups which match `regular expressions `__. There are various visual changes when a group is frozen. The highlight color in the group list changes to light green and all the widgets on the main window become disabled. When a group is frozen, direct edits of parameter values are disallowed. Frozen groups are skipped for algorithmic edits, such as parameter constraints or alignment. You can, however, still remove a frozen group from the project. Unfreezing a group is a simple as hitting :button:`Alt`-:button:`f` again.