请教ultrasim问题

hongmy

spfrcnet

在看ultrasim的帮助时的问题，请教下面红色的这段是什么意思？
   寄生电容和电阻被提取出来后，我们不是已经认为他是属于集总参数吗？parasitic capacitor与lumped capacitance，这两个为什么会来一个二选一，是对立的吗？


Spectre Syntax
usim_opt spfrcnet=net_name
SPICE Syntax
.usim_opt spfrcnet=net_name
Description
This option specifies the name of the net to be stitched with parasitic resistors and capacitors.
The other nets are stitched with lumped capacitances. Multiple nets can be specified on
separate lines.
Example
Spectre Syntax:
usim_opt spfrcnet=vcc
usim_opt spfrcnet=gnd
SPICE Syntax:
.usim_opt spfrcnet=vcc
.usim_opt spfrcnet=gnd
tells the virtuoso UltraSim simulator to stitch parasitic resistors and capacitors for both vcc
and gnd nets and to stitch all other nets with lumped capacitances.