implement an "ECL output interval"

i.e., the ECL restart files are not necessarily updated after each
report step, but only each N-th (where N is the number specified by
the EclOutputInterval parameter). if this value is set to something
smaller than zero, the value which is computed by the EclipseState
object is used.

ebos/eclbasevanguard.hh

@@ -63,9 +63,11 @@ NEW_PROP_TAG(EquilGrid);
 NEW_PROP_TAG(Scalar);
 NEW_PROP_TAG(EclDeckFileName);
 NEW_PROP_TAG(EclOutputDir);
+NEW_PROP_TAG(EclOutputInterval);
 
 SET_STRING_PROP(EclBaseVanguard, EclDeckFileName, "ECLDECK.DATA");
 SET_STRING_PROP(EclBaseVanguard, EclOutputDir, ".");
+SET_INT_PROP(EclBaseVanguard, EclOutputInterval, -1); // use the deck-provided value
 
 END_PROPERTIES
 
@@ -101,6 +103,8 @@ public:
                              "The name of the file which contains the ECL deck to be simulated");
         EWOMS_REGISTER_PARAM(TypeTag, std::string, EclOutputDir,
                              "The directory to which the ECL result files are written");
+        EWOMS_REGISTER_PARAM(TypeTag, int, EclOutputInterval,
+                             "The number of report steps that ought to be skipped between two writes of ECL results");
     }
 
     /*!
@@ -227,6 +231,12 @@ public:
         // the eclState is supposed to be immutable here, IMO.
         ioConfig.setOutputDir(outputDir);
 
+        // Possibly override IOConfig setting for how often RESTART files should get
+        // written to disk (every N report step)
+        int outputInterval = EWOMS_GET_PARAM(TypeTag, int, EclOutputInterval);
+        if (outputInterval >= 0)
+            eclState_->getRestartConfig().overrideRestartWriteInterval(outputInterval);
+
         asImp_().createGrids_();
         asImp_().filterCompletions_();
         asImp_().finalizeInit_();