should we define "ligation_site_regex" if we choose enzyme "none"?

[shengqh]

Currently, we set enzyme "none" and didn't set ligation_site_regex in configuration json file since we used MNase. Based on the wdl code, the ligation_site would be determined as "XXXX" in hic-pipeline. However, in call-calculate_stats_on_library task, the stats_0_lib0.txt looks weird. Should we set ligation_site_regex to something else even the enzyme is none?

Read type: Paired End
Sequenced Read Pairs: 4144224
No chimera found: 187008411 (4512.51%)
One or both reads unmapped: 187008411 (4512.51%)
2 alignments: 72160909 (1741.24%)
2 alignments (A...B): 43056597 (1038.95%)
2 alignments (A1...A2B; A1B2...B1A2): 29104312 (702.29%)
3 or more alignments: 0 (0.00%)
Ligation Motif Present: N/A
Average insert size: 0.00
Total Unique: -68843076 (-95.40%, -1661.18%)
Total Duplicates: 141003985 (195.40%, 3402.42%)