# Criterion Function

Criterion Function — MC Grating documentation for Modal Crossed and Chandezon Crossed. The Optimization procedure objective is the minimum mean-square…

Canonical: https://mcgrating.com/docs/common-crossed/criterion.html


Written by Nikolay M. LyndinLast revised 2012-12-18

This documentation was written for releases up to 2018 and is being revised. Some dialogs have changed since. If something does not match what you see, write to [mc@mcgrating.com](mailto:mc@mcgrating.com).

The Optimization procedure objective is the minimum mean-square deviation of the user defined values assigned in the *Criterion Function* from the calculated values. The user can construct this function in the form of a number of (***Number of Points***) completely independent criterion points. The ***Point*** control provides the possibility to select the criterion point index. By clicking the mouse right button at this control the user activates the *Popup Menu* for editing the criterion points.
 Every criterion point targets the assigned power of the given diffraction order (edit control ***Value***) with the ***Weighting Factor*** of this criterion point within the whole criterion function and its characteristics (***Diffraction Order*** and ***Cover/Substrate*** propagation). The ***Output Polarizer*** and its orientation (edit control ***Angle***) is an additional criterion point characteristic. All these characteristics are placed in the ***Criterion Diffraction Order Power*** panel. The right hand ***Criterion Arguments ***panel contains other parameters. These arguments are: the polarization type, the incident conditions ***Normal Angle***, ***Plane Angle***, ***Wavelength*** and the grating ***X-Period ***and ***Y-Period***. The edit controls of the corresponding ***Variable*** parameters are inactive.

During the ***[Optimization](https://mcgrating.com/docs/common/optimization.html)*** process these two panels are inactive, but at the bottom of the left panel under the label ***Current Power Value*** the user can see the updated every second power of the appropriate diffracted wave. In addition this information will be updated every time the user changes the criterion ***Point*** index.

From the in-application help of Modal Crossed, documented through 2018. If you publish results computed with MC Grating, see [how to cite it](https://mcgrating.com/references.html#cite).