Prepare Cshunt: add a cpacitor to each voltage node

Function inppas4() will add the extra caps, to be done.

src/frontend/inp.c

@@ -1336,6 +1336,10 @@ inp_dodeck(
         }
     } // if (!noparse)  . . .
 
+    /* If option cshunt is given, add capacitors to each voltage node */
+    if (ft_curckt->ci_defTask->TSKcshunt > 0.)
+        INPpas4(ckt, tab);
+
     /* add title of deck to data base */
     /* this won't work if the title is the empty string
     *    cp_addkword() doesn't work for tt === ""

src/include/ngspice/cktdefs.h

@@ -215,6 +215,7 @@ struct CKTcircuit {
 #endif /* NEWTRUNC */
     double CKTgmin;             /* .options GMIN */
     double CKTgshunt;           /* .options RSHUNT */
+    double CKTcshunt;           /* .options CSHUNT */
     double CKTdelmin;           /* minimum time step for tran analysis */
     double CKTtrtol;            /* .options TRTOL */
     double CKTfinalTime;        /* TSTOP */

src/include/ngspice/inpdefs.h

@@ -136,6 +136,7 @@ void INPpas1(CKTcircuit *, struct card *, INPtables *);
 void INPpas2(CKTcircuit *, struct card *, INPtables *, TSKtask *);
 void INPpas3(
         CKTcircuit *, struct card *, INPtables *, TSKtask *, IFparm *, int);
+void INPpas4(CKTcircuit *, INPtables *);
 int INPpName(char *, IFvalue *, CKTcircuit *, int, GENinstance *);
 int INPtermInsert(CKTcircuit *, char **, INPtables *, CKTnode **);
 int INPtermSearch(CKTcircuit*, char**, INPtables*, CKTnode**);

src/include/ngspice/optdefs.h

@@ -120,6 +120,7 @@ enum {
     OPT_XMU,
     OPT_INDVERBOSITY,
     OPT_EPSMIN,
+    OPT_CSHUNT,
 };
 
 #ifdef XSPICE

src/include/ngspice/tskdefs.h

@@ -51,6 +51,7 @@ struct TSKtask {
 #endif /* NEWTRUNC */
     double TSKgmin;
     double TSKgshunt;   /* shunt conductance (CKTdiagGmin) */
+    double TSKcshunt;   /* shunt capacitor to ground */
     double TSKdelmin;
     double TSKtrtol;
     double TSKdefaultMosM;

src/spicelib/analysis/cktdojob.c

@@ -71,6 +71,7 @@ CKTdoJob(CKTcircuit *ckt, int reset, TSKtask *task)
     ckt->CKTvoltTol  = task->TSKvoltTol;
     ckt->CKTgmin  = task->TSKgmin;
     ckt->CKTgshunt  = task->TSKgshunt;
+    ckt->CKTcshunt  = task->TSKcshunt;
     ckt->CKTdelmin  = task->TSKdelmin;
     ckt->CKTtrtol  = task->TSKtrtol; 
 #ifdef XSPICE

src/spicelib/analysis/cktntask.c

@@ -86,6 +86,7 @@ CKTnewTask(CKTcircuit *ckt, TSKtask **taskPtr, IFuid taskName, TSKtask **defPtr)
         /* use the application defaults */
         tsk->TSKgmin            = 1e-12;
         tsk->TSKgshunt          = 0;
+        tsk->TSKcshunt          = -1;
         tsk->TSKabstol          = 1e-12;
         tsk->TSKreltol          = 1e-3;
         tsk->TSKchgtol          = 1e-14;

src/spicelib/analysis/cktsopt.c

@@ -172,6 +172,9 @@ CKTsetOpt(CKTcircuit *ckt, JOB *anal, int opt, IFvalue *val)
     case OPT_EPSMIN:
         task->TSKepsmin = val->rValue;
         break;
+    case OPT_CSHUNT:
+        task->TSKcshunt = val->rValue;
+        break;
 /* gtri - begin - wbk - add new options */
 #ifdef XSPICE
     case OPT_EVT_MAX_OP_ALTER:
@@ -238,6 +241,7 @@ static IFparm OPTtbl[] = {
  { "rshunt", OPT_ENH_RSHUNT, IF_SET|IF_REAL, "Shunt resistance from analog nodes to ground" },
 /* gtri - end   - wbk - add new options */
 #endif
+ { "cshunt", OPT_CSHUNT, IF_SET|IF_REAL, "Shunt capacitor from analog nodes to ground" },
  { "noopiter", OPT_NOOPITER,IF_SET|IF_FLAG,"Go directly to gmin stepping" },
  { "gmin", OPT_GMIN,IF_SET|IF_REAL,"Minimum conductance" },
  { "gshunt", OPT_GSHUNT,IF_SET|IF_REAL,"Shunt conductance" },

visualc/vngspice.vcxproj

@@ -1336,6 +1336,7 @@
     <ClInclude Include="..\src\spicelib\parser\inppas1.h" />
     <ClInclude Include="..\src\spicelib\parser\inppas2.h" />
     <ClInclude Include="..\src\spicelib\parser\inppas3.h" />
+    <ClInclude Include="..\src\spicelib\parser\inppas4.h" />
     <ClInclude Include="..\src\spicelib\parser\inpxx.h" />
     <ClInclude Include="..\src\winmain.h" />
     <ClInclude Include=".\src\include\inttypes.h" />
@@ -2655,6 +2656,7 @@
     <ClCompile Include="..\src\spicelib\parser\inppas1.c" />
     <ClCompile Include="..\src\spicelib\parser\inppas2.c" />
     <ClCompile Include="..\src\spicelib\parser\inppas3.c" />
+    <ClCompile Include="..\src\spicelib\parser\inppas4.c" />
     <ClCompile Include="..\src\spicelib\parser\inppname.c" />
     <ClCompile Include="..\src\spicelib\parser\inpptree.c" />
     <ClCompile Include="..\src\spicelib\parser\inpsymt.c" />