Add set for realized time steps

Set `t_realized(t)` has the realized time steps in the simulation (excluding the starting point and any extra horizon).
This is included in file *results.gdx* as symbol `t`.

Closes #81

defOutput/resultSymbols.inc

@@ -19,6 +19,9 @@ $offtext
 * --- Results Symbols Included in Output --------------------------------------
 * =============================================================================
 
+* --- Symbols related to the simulation setup ---------------------------------
+t_realized = t
+
 * --- Cost Result Symbols -----------------------------------------------------
 
 // Total Objective Function

inc/1b_sets.gms

@@ -96,6 +96,7 @@ Sets
     t_current(t) "Set of time steps within the current solve horizon"
     t_active(t) "Set of active t:s within the current solve horizon, including necessary history"
     t_invest(t) "Time steps when investments can be made"
+    t_realized(t) "Set of realized time steps in the simulation"
     tt(t) "Temporary subset for time steps used for calculations"
     tt_(t) "Another temporary subset for time steps used for calculations"
     tt_block(counter, t) "Temporary time step subset for storing the time interval blocks"

inc/3a_periodicInit.gms

@@ -49,6 +49,12 @@ loop(m,
         abort "t_end is not divisible by t_jump";
     );
 
+    // Calculate realized timesteps in the simulation
+    t_realized(t_full(t))${ ord(t) >= mSettings(m, 't_start') + 1
+                            and ord(t) <= mSettings(m, 't_end') + 1
+                          }
+        = yes;
+
 * --- Samples and Forecasts ---------------------------------------------------
 $ontext
     // Check that forecast length is feasible