ParamDefinition: save initial value for dicho calculated params

src/param/param-definition.ts

@@ -772,6 +772,13 @@ export class ParamDefinition implements INamedIterableValues, IObservable {
                 paramRep.value = this.singleValue;
                 break;
 
+            case ParamValueMode.CALCUL:
+                // save initial value if param is calculated using dichotomy
+                if (this.calculability === ParamCalculability.DICHO) {
+                    paramRep.value = this.singleValue;
+                }
+                break;
+
             case ParamValueMode.MINMAX:
                 paramRep.min = this.min;
                 paramRep.max = this.max;
@@ -874,6 +881,9 @@ export class ParamDefinition implements INamedIterableValues, IObservable {
             case ParamValueMode.CALCUL:
                 // although calculated param is set at Nub level (see below),
                 // it is detected as "the only parameter in CALC mode"
+                if (obj.value !== undefined) { // dichotomy params have an initial value, others don't
+                    this.singleValue = obj.value;
+                }
                 ret.calculated = true;
                 break;