luke
/
ngspice
mirror of https://git.code.sf.net/p/ngspice/ngspice
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

enable removal of dangling nodes also when MODETRANOP is set. 

Removes singular nodes when op before tran is run.
This commit is contained in:
Holger Vogt 2026-07-03 14:11:02 +02:00
parent 6272cbaf1b
commit a86356980a
1 changed files with 18 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
src/spicelib/devices/cap/capload.c
View File

@ -49,20 +49,25 @@ CAPload(GENmodel *inModel, CKTcircuit *ckt)
vcap = *(ckt->CKTrhsOld+here->CAPposNode) -
*(ckt->CKTrhsOld+here->CAPnegNode) ;
}
if (here->CAPdangling) {
/* Topology reduction: this cap hangs on a
* floating (degree-1) node. Remove it from the system:
* pin the floating node(s) with a unit diagonal so the
* matrix stays nonsingular, and contribute no charge or
* current. This eliminates the spurious LTE pressure
* that otherwise drives "Timestep too small" at the
* dangling node (set in CKTtopologyReduce()). */
if (here->CAPdangling & 1)
*(here->CAPposPosPtr) += 1.0;
if (here->CAPdangling & 2)
*(here->CAPnegNegPtr) += 1.0;
*(ckt->CKTstate0+here->CAPqcap) = 0.0;
continue;
}
if(ckt->CKTmode & (MODETRAN | MODEAC)) {
if (here->CAPdangling) {
/* Topology reduction: this cap hangs on a
* floating (degree-1) node. Remove it from the system:
* pin the floating node(s) with a unit diagonal so the
* matrix stays nonsingular, and contribute no charge or
* current. This eliminates the spurious LTE pressure
* that otherwise drives "Timestep too small" at the
* dangling node (set in CKTtopologyReduce()). */
if (here->CAPdangling & 1) *(here->CAPposPosPtr) += 1.0;
if (here->CAPdangling & 2) *(here->CAPnegNegPtr) += 1.0;
*(ckt->CKTstate0+here->CAPqcap) = 0.0;
continue;
}
#ifndef PREDICTOR
if(ckt->CKTmode & MODEINITPRED) {
*(ckt->CKTstate0+here->CAPqcap) =