-if (rnaStruc == null || !rnaStruc.isValidStruc ()) {\r
-this.calcMan.workerComplete (this);\r
-return;\r
-}try {\r
-var arr = alignment.getSequencesArray ();\r
-this.nseq = arr.length;\r
-jalview.analysis.StructureFrequency.calculate (arr, 0, alignment.getWidth (), this.hStrucConsensus, true, rnaStruc);\r
-} catch (x) {\r
-if (Clazz.exceptionOf (x, ArrayIndexOutOfBoundsException)) {\r