Hi Ankita,
This looks like a misunderstanding about the purpose of that parameter. As explained in the
User Guide on the
Run GSEA Page, this parameter simply controls the "Number of features (gene or probes) to include in the butterfly plot in the Gene Markers section of the gene set enrichment report." It need not - and in fact
should not - match the number of features in the dataset.
As that page points out, the entire Advanced Fields section of parameters should be avoided unless you're highly familiar with GSEA. While this parameter could quite arguably have a better name, it's best to leave all of these set at their defaults in general unless directed otherwise. I'll make a note of the changing the parameter name for a possible future release, though.
Regarding the max & min thresholds, these are related to the number of matches from the Gene Set (GMT, GMX, or GRP) rather than the number of genes in the dataset. Again, especially with MSigDB Gene Sets, there should be no need to change these other than minor tweaking.
By the way, it's best to work with full datasets (thousands of genes) rather than filtered lists as otherwise it blunts the statistical power of GSEA.
Regards,
David Eby