我在官网上找到了答案。
The NETLIST_MINRES_HANDLING: MERGE will not work on resistor nodes with
more than 3 branches. This means it will do only series merging. However,
NETLIST_MINRES_HANDLING: SHORT will work on all resistor nodes and short the
nodes appropriately. merge不工作超过3个分支,只做串联的合并。