Arc decoder (#287)

[quantumjim]

• fix issue with string2nodes

• ignore undeeded boundary nodes option

• correct given nodes issue

• make non-neutral cluster if contains only boundary

• improvements to check_nodes

• check nodes also outputs error_num

• check_nodes also outputs error_num

• add check_nodes to RepetitionCodeCircuits

• black

• add decoder

• make decoder compatible with RepCodeCircs

• lint and black

• add tests for clustering decoder

• have check nodes output flipped logicals as nodes

• check_nodes outputs flipped logicals as nodes

• check_nodes outputs flipped logicals as nodes

• undo weirdness

Co-authored-by: grace-harper-ibm 74260313+grace-harper-ibm@users.noreply.github.com

Summary

Details and comments