def update(self, strand5p: StrandT, idx: int = None):
"""Pass ``idx`` to this method in order to install a floating
Xover for the forced xover tool
Args:
strand5p: Description
idx: Default is ``None``
"""
self._strand5p = strand5p
strand3p = strand5p.connection3p()
vhi5p = self._virtual_helix_item
part_item = vhi5p.partItem()
# This condition is for floating xovers
idx_3_prime = idx if idx else strand5p.idx3Prime()
if self._node5 is None:
self._node5 = XoverNode5(vhi5p, self, strand5p, idx_3_prime)
if strand3p is not None:
if self._node3 is None:
vhi3p = part_item.idToVirtualHelixItem(strand3p.idNum())
self._node3 = XoverNode3(vhi3p, self, strand3p,
strand3p.idx5Prime())
else:
self._node5.setIdx(idx_3_prime)
self._node3.setIdx(strand3p.idx5Prime())
self._node5.setPartnerVirtualHelix(strand5p)
self._updatePath(strand5p)
else:
if self._node3:
self._node3.destroyItem()
self._node3 = None
def canInstallXoverAt(self, idx: int,
from_strand: StrandT,
from_idx: int) -> bool:
"""Assumes idx is:
self.lowIdx() <= idx <= self.highIdx()
"""
if self.hasXoverAt(idx):
return False
ss = self.strandSet()
is_same_strand = from_strand == self
is_forward = ss.isForward()
index_diff_H = self.highIdx() - idx
index_diff_L = idx - self.lowIdx()
idx3p = self.idx3Prime()
idx5p = self.idx5Prime()
# ensure 2 bps from 3p end if not the 3p end
index3_lim = idx3p - 1 if is_forward else idx3p + 1
if is_same_strand:
index_diff_strands = from_idx - idx
if idx == idx5p or idx == index3_lim:
return True
elif index_diff_strands > -3 and index_diff_strands < 3:
return False
# end if for same Strand
else:
from_idx3p = from_strand.idx3Prime()
from_idx5p = from_strand.idx5Prime()
if idx == idx5p or idx == index3_lim:
if from_idx3p == from_idx:
return True
elif (abs(from_idx3p - from_idx) > 1 and
abs(from_idx5p - from_idx) > 1):
return True
else:
# print("this:", idx, idx3p, idx5p)
# print("from:", from_idx, from_idx3p, from_idx5p)
return False
elif index_diff_H > 2 and index_diff_L > 1:
if from_idx3p == from_idx:
return True
elif (abs(from_idx3p - from_idx) > 1 and
abs(from_idx5p - from_idx) > 1):
return True
else:
return False
else:
# print("default", index_diff_H, index_diff_L)
return False