modification not defined in the optimal position of the peptide for a match

[lutzfischer]

Some times the modification a peptide is selected as the "correct" one for a match where the modification site id clearly wrong.
Example:
SearchID: 12828
PSMID: 7684197169
Scan: 27259

The sda modification should be on the lysine not the serine.

[lutzfischer]

just some notes for me:
largest precursor in the sample is mapped by:
E130808_11_Quty1_AB_DE_220_V127_K_6_666ul Index: 20025 Precursor: 0 multi
the offending scan is
E130808_12_Quty1_AB_DE_220_V127_L_6_666ul Index: 27259

[lutzfischer]

problem here was that peptides had 4 possible modification sites for 2 distinct modifications and that gave a combinatoric of 80 possible modified peptides and only 20 are considered.
currently this can not be circumvented do to the issue #302

[lutzfischer]

One way to address this would be to test at the point of matching what modification would work best where. but this would make the matching a lopt more complecated. Especially do to the way modifications are represented in xi