If compatmode hs is set, don't run an extra iteration with

differing mode settings, but go directly to CKTop().
If other or none compat modes, keep existing behavior, as
for example CIDER example may otherwise slow down significantly.

This is to keep dc sim in accordance with other simulators.

src/spicelib/analysis/dctrcurv.c

@@ -14,6 +14,7 @@ Modified: 1999 Paolo Nenzi
 #include "ngspice/const.h"
 #include "ngspice/sperror.h"
 #include "ngspice/fteext.h"
+#include "ngspice/compatmode.h"
 
 #ifdef XSPICE
 #include "ngspice/evt.h"
@@ -297,8 +298,8 @@ DCtrCurv(CKTcircuit *ckt, int restart)
         if (ckt->evt->counts.num_insts == 0) {
             /* If no event-driven instances, do what SPICE normally does */
 #endif
-            converged = NIiter(ckt, ckt->CKTdcTrcvMaxIter);
-            if (converged != 0) {
+
+            if (newcompat.hs) {
                 converged = CKTop(ckt,
                                   (ckt->CKTmode & MODEUIC) | MODEDCTRANCURVE | MODEINITJCT,
                                   (ckt->CKTmode & MODEUIC) | MODEDCTRANCURVE | MODEINITFLOAT,
@@ -306,6 +307,17 @@ DCtrCurv(CKTcircuit *ckt, int restart)
                 if (converged != 0)
                     return(converged);
             }
+            else {
+                converged = NIiter(ckt, ckt->CKTdcTrcvMaxIter);
+                if (converged != 0) {
+                    converged = CKTop(ckt,
+                        (ckt->CKTmode & MODEUIC) | MODEDCTRANCURVE | MODEINITJCT,
+                        (ckt->CKTmode & MODEUIC) | MODEDCTRANCURVE | MODEINITFLOAT,
+                        ckt->CKTdcMaxIter);
+                    if (converged != 0)
+                        return(converged);
+                }
+            }
 #ifdef XSPICE
         }
         else {