. If you are unfamiliar with this argument you should refer to
in the Introduction to the NAG Library FL Interface for details.
For environments where it might be inappropriate to halt program execution when an error is detected, the value
is recommended. If the output of error messages is undesirable, then the value
is recommended. Otherwise, because for this routine the values of the output arguments may be useful even if
on exit, the recommended value is
. When the value is used it is essential to test the value of ifail on exit.