FunctionQDepends¶

Description¶

This fitting function is the base class for all fitting functions that have:

• A range of energy transfers as their one-dimensional domain from which to take values
• The magnitude of the momemtum transfer, $Q$, as one of their attributes.

Fitting functions for QENS data depending on $Q$ should derive from this class.

There are two ways to update attribute $Q$ in the fit function:

• The user inputs a particular value.
• The spectrum contains $Q$ in addition to the range of energy transfers.

Conflict may arise when both options are available. In that case, priority is given to the $Q$-value contained in the spectrum. Here are some user cases:

• User cannot override the value of attribute $Q$ if the spectrum contains a $Q$-value.
• User can set or update the value of of attribute $Q$ is the spectrum does not contain a $Q$-value.
• The value of attribute $Q$ will be updated everytime we pass a new spectrum containing a $Q$-value.
• The value of attribute $Q$ will be erased if we pass a new spectrum not containing a $Q$-value. In this case it is the responsibility of the user to set the appropriate value.