ReplaceIndex

• ReplaceIndex[expr, rules] replaces indices of objects in expr as given by rules (a single rule or a list of rules of the form i1->i2). Note that the rules a->b and -a->-b are independent and both must be given if this is what we want.
• ReplaceIndex[expr, {rules1, rules2, ...}] is automatically threaded, giving a list of expressions.

• It is possible to change any valid index by any other expression, not necessarily an index. That is, there is no check on the RHS of the rules.
• The function tries to change first the basis indices as a whole and, if no rule applies, then the internal abstract index of the basis indices is changed.
• Patterns can be changed but a `Contact JMM´ message is sent.
• Blocked indices (components, directions and labels) can be changed.
• ReplaceIndex has attribute HoldFirst, and hence requires very often the use of Evaluate.
• See: Section 2.9.
• See also: SplitIndex, ReplaceDummies, SameDummies.
• New in version 0.
• Last update: 24-IX-2007 for version 0.9.3 of xTensor`.

Created by Mathematica  (May 16, 2008)