Attribute Calculator Attribute Calculator icon

Attribute Calculator generates new numerical attributes from existing ones. The calculated attribute values, or even simply the values of an existing attribute, can be written to a file.

There are several ways to start Attribute Calculator, a tool in the Structure Analysis category.

One must specify a name for the attribute to be created and whether it will be an attribute of atoms, residues, or molecules (molecule models). The name must be an alphanumeric string without spaces; it can include underscores, but should not begin with a underscore, digit, or capital letter. Atom attributes with names containing area, volume, or charge (after word separation by camel case and/or underscores) will be totaled automatically to give the corresponding residue attributes.

The Formula is an arithmetic expression. Supported operators are + (addition), (subtraction), * (multiplication), and / (division). Parentheses can be used for grouping.

Terms in the expression can be: Several options further affect the calculation and attribute assignment:

OK performs the calculation/assignment and dismisses the dialog. Apply performs the calculation/assignment without dismissing the dialog. Close dismisses the dialog, and Help opens this manual page in a browser window.

The formula is not reevaluated automatically; if any constituent attribute values change, OK or Apply must be used again to recalculate the result with the new values.

UCSF Computer Graphics Laboratory / March 2014