next up previous contents
Next: Energy Budget Up: Problems and Pitfalls Previous: The Ionizing Spectrum   Contents

The use of critf

This input parameter allows the user to control the size of the matrix solved when calculating level populations.

In versions 2.1lxx and before this matrix had a maximum size of 2400, and an attempt to solve for more than this number of levels simultaneously would result in xstar stopping with a message `ipmat too large'. This is most likely to occur in situations where more than 4 or 5 of the lower ion stages of iron meet the critf criterion; for problems with zero iron abundance critf can probably be specified as small as 1.e-15; when iron is non-zero the limit may be reached if critf is less than 1.e-8.

With version 2.2 this is no longer true and small values of this parameter are recommended.



Tim Kallman 2014-09-12