When NGSPICE performs a transient simulation with initial conditions, it

prints out an "Initial Transient Solution" and plots the first timestep.

This is despite the fact that the first timestep is not meaningful when
initial conditions are applied. The first "real" output is available
only after the second transient timestep.

This patch suppresses "Initial Transient Solution" output and
plotting for the first timestep.

src/spicelib/devices/ind/indload.c

@@ -59,15 +59,24 @@ INDload(GENmodel *inModel, CKTcircuit *ckt)
                 muthere=MUTnextInstance(muthere)) {
 
             if(!(ckt->CKTmode& (MODEDC|MODEINITPRED))) {
-                *(ckt->CKTstate0 + muthere->MUTind1->INDflux)  +=
-                    muthere->MUTfactor * *(ckt->CKTrhsOld +
-                                           muthere->MUTind2->INDbrEq);
+                /* set initial conditions for mutual inductance here, if uic is set */
+                if (ckt->CKTmode & MODEUIC && ckt->CKTmode & MODEINITTRAN) {
+                   *(ckt->CKTstate0 + muthere->MUTind1->INDflux) +=
+                        muthere->MUTfactor * muthere->MUTind2->INDinitCond;
 
-                *(ckt->CKTstate0 + muthere->MUTind2->INDflux)  +=
-                    muthere->MUTfactor * *(ckt->CKTrhsOld +
-                                           muthere->MUTind1->INDbrEq);
+                   *(ckt->CKTstate0 + muthere->MUTind2->INDflux) +=
+                        muthere->MUTfactor * muthere->MUTind1->INDinitCond;
+                }
+                else {
+                    *(ckt->CKTstate0 + muthere->MUTind1->INDflux) +=
+                        muthere->MUTfactor * *(ckt->CKTrhsOld +
+                            muthere->MUTind2->INDbrEq);
+
+                    *(ckt->CKTstate0 + muthere->MUTind2->INDflux) +=
+                        muthere->MUTfactor * *(ckt->CKTrhsOld +
+                            muthere->MUTind1->INDbrEq);
+                }
             }
-
             *(muthere->MUTbr1br2Ptr) -= muthere->MUTfactor*ckt->CKTag[0];
             *(muthere->MUTbr2br1Ptr) -= muthere->MUTfactor*ckt->CKTag[0];
         }