Added multiplicity parameter m to resistors and updated tests

DEVICES

@@ -19,8 +19,8 @@ IND - Inductor
 RES - Resistor
       This is a modified version of the spice3 resistance model. This
       model supports different ac and dc values (ac=...). This changes
-      are introduced by Serban Popescu. This device needs more
-      testing.
+      are introduced by Serban Popescu. The "multiplicity factor" (m) 
+      has been introduced.
       
       *)Rework 11: The code has been modified to reflect spice parsing
         standard. 

src/spicelib/devices/res/res.c

@@ -16,6 +16,7 @@ IFparm RESpTable[] = { /* parameters */
  IOPZU( "temp",        RES_TEMP,   IF_REAL,"Instance operating temperature"),
  IOPQU( "l",          RES_LENGTH, IF_REAL,"Length"),
  IOPZU( "w",          RES_WIDTH,  IF_REAL,"Width"),
+ IOPU( "m", RES_M, IF_REAL, "Multiplication factor"),
  IP(   "sens_resist", RES_RESIST_SENS, IF_FLAG,   
         "flag to request sensitivity WRT resistance"),
  OP( "i",          RES_CURRENT,IF_REAL,"Current"),

src/spicelib/devices/res/resask.c

@@ -43,9 +43,12 @@ RESask(CKTcircuit *ckt, GENinstance *inst, int which, IFvalue *value,
         case RES_LENGTH:
             value->rValue = fast->RESlength;
             return(OK);
-        case RES_WIDTH :
+        case RES_WIDTH:
             value->rValue = fast->RESwidth;
             return(OK);
+	case RES_M:
+	    value->rValue = fast->RESm;
+	    return(OK);
         case RES_QUEST_SENS_DC:
             if(ckt->CKTsenInfo){
                 value->rValue = *(ckt->CKTsenInfo->SEN_Sap[select->iValue + 1]+

src/spicelib/devices/res/resdefs.h

@@ -36,6 +36,7 @@ typedef struct sRESinstance {
     double RESacConduct; /* AC conductance */
     double RESwidth;    /* width of the resistor */
     double RESlength;   /* length of the resistor */
+    double RESm;        /* Multiplicity factor for this instance */
     double *RESposPosptr;    /* pointer to sparse matrix diagonal at 
                               * (positive,positive) */
     double *RESnegNegptr;    /* pointer to sparse matrix diagonal at 
@@ -49,7 +50,8 @@ typedef struct sRESinstance {
     unsigned RESlengthGiven : 1;    /* flag to indicate length given */
     unsigned REStempGiven   : 1;    /* indicates temperature specified */
 /* serban */
-    unsigned RESacresGiven   : 1;   /* indicates AC value specified */
+    unsigned RESacresGiven  : 1;    /* indicates AC value specified */
+    unsigned RESmGiven      : 1;    /* indicates M parameter specified */
     int    RESsenParmNo;         /* parameter # for sensitivity use;
                 set equal to  0 if not a design parameter*/
 #ifndef NONOISE
@@ -97,6 +99,7 @@ typedef struct sRESmodel {       /* model structure for a resistor */
 /* serban */
 #define RES_ACRESIST 10
 #define RES_ACCONDUCT 11
+#define RES_M 12 /* pn */
 
 
 /* model parameters */

src/spicelib/devices/res/resparam.c

@@ -39,6 +39,10 @@ RESparam(int param, IFvalue *value, GENinstance *inst, IFvalue *select)
             break;
         case RES_RESIST_SENS:
             here->RESsenParmNo = value->iValue;
+	    break;
+	case RES_M:
+	    here->RESm = value->rValue;
+	    here->RESmGiven = TRUE;
             break;
         default:
             return(E_BADPARM);

src/spicelib/devices/res/restemp.c

@@ -64,9 +64,14 @@ REStemp(GENmodel *inModel, CKTcircuit *ckt)
 
             here->RESconduct = 1.0/(here->RESresist * factor);
 	    
+	    if(here->RESmGiven)
+	      here->RESconduct = here->RESconduct * here->RESm;
+	    
 	    /* Paolo Nenzi: Temperature effects for AC value */
 	    if(here->RESacresGiven) 
 	       here->RESacConduct = 1.0/(here->RESacResist * factor);
+	    if (here->RESmGiven)
+	       here->RESacConduct = here->RESacConduct * here->RESm;
         }
     }
     return(OK);

tests/resistor.cir

@@ -1,9 +1,24 @@
-A simple resistor with a voltage source
+A paralled resistor array
 
-R1 1 0 10k
-V1 1 0 1
+Vin 1 0 DC 1 SIN (0 1 100MEG 1NS 0.0) AC 1
 
-.TRAN 1ns 6ns
-.PRINT TRAN I(V1)
+VR1 1 2 DC 0
+R1  2 0 10K
+
+VR2 1 3 DC 0
+R2  3 0 10K ac=5K
+
+VR3 1 4 DC 0
+R3  4 0 rmodel1 L=11u W=2u ac=2.5k
+
+VR4 1 5 DC 0
+R4  5 0 10K ac=5k m=2
+.model rmodel1 R  RSH = 1000 NARROW = 1u
+
+.OP
+.TRAN 1ns 10ns
+.AC DEC 100 1MEG 100MEG
+.PRINT TRAN I(VR1), I(VR2), I(VR3), I(VR4)
+.PRINT AC I(VR1), I(VR2), I(VR3), I(VR4)
 
 .END