Editing Input syntax manual (section)

=== set xscalc ===

 '''set xscalc''' ''MODE'' 

Calculation mode for transmutation cross sections. Input values:

{|
| <tt>''MODE''</tt> 
| : Calculation mode (1 = direct tallies, 2 = spectrum-collapse)
|}

<u>Notes:</u>

*This parameter controls the way transmutation cross sections are calculated in burnup mode. 
**In spectrum-collapse mode these cross sections are calculated after the transport simulation, using a fine-group spectrum collected for each material.
**The spectrum-collapse mode leads to improved performance, but also increased memory footprint per depletion zone (see [[#set opti|set opti]]).
*The option is automatically set when using optimization modes, and it is not recommended to be defined manually.
**Many of the old example input files set spectrum collapse method on, which overrides the behaviour in lower optimization modes.