Debugging &homalg; Beside the &GAP; builtin debugging facilities (&see; ) &homalg; provides two ways to debug the computations.
Increase the assertion level &homalg; comes with numerous builtin assertion checks. They are activated if the user increases the assertion level using
SetAssertionLevel( level );
(&see; ), where level is one of the values below:

level description
0 no assertion checks whatsoever
3 high-level homological assertions are checked
4 mid-level homological assertions are checked
5 low-level homological assertions are checked
6 assertions about basic matrix operations are checked (&see; Appendices of the &MatricesForHomalg; package)
(these are among the operations often delegated to external systems)

In particular, if &homalg; delegates matrix operations to an external system then SetAssertionLevel( 4 ); can be used to let &homalg; debug the external system.