refactor: Remous: make Z1,Z2 optionally undefined

refs #343

src/open-channel/remous.ts

@@ -547,6 +547,16 @@ export class CourbeRemous extends SectionNub {
         return this._prms as CourbeRemousParams;
     }
 
+    public isComputable(): boolean {
+        if (super.isComputable()) {
+            // au moins Z1 ou Z2 doit être défini
+            const z1 = this.prms.Z1;
+            const z2 = this.prms.Z2;
+            return z1.isDefined || z2.isDefined;
+        }
+        return false;
+    }
+
     /**
      * Retourne la cote de fond à l'abscisse x
      * @param x abscisse en m (0 = amont)

src/open-channel/remous_params.ts

-import { ParamDefinition, ParamFamily } from "../internal_modules";
+import { ParamDefinition, ParamDomain, ParamFamily } from "../internal_modules";
 import { ParamDomainValue } from "../internal_modules";
 import { ParamsEquation } from "../internal_modules";