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Exercise objective:
· Making easy re-runs
Suggested reading:
Chapter 7.6 of the book, ORYZA2000: modelling lowland rice.
ORYZA2000 can make automatic reruns. In a rerun, ORYZA2000 is executed again with new values for selected parameters.
Exercise:
Reruns can be executed for all parameters, initial states, and variable names occurring in all input data files, and for the names of all input files specified in the control file CONTROL.DAT. Functions can also be redefined in a rerun file. All parameter variables and data files that are not redefined in the so-called rerun file (RERUNS.DAT) retain their original values. More than one rerun can be defined in the rerun file and there is no limit to the number of reruns that can be made. Names of variables originating from different data files can be redefined in the same rerun file. However, the order and number of the variables should be the same in each so-called rerun set. A new set starts when the first variable name is repeated. The name of the rerun data file is defined in the CONTROL.DAT file. If the rerun file is empty, or absent, ORYZA2000 will be executed just once with the settings and input data files specified in the CONTROL.DAT file.
Ex-I.50. Read the CONTROL.DAT file and verify that the experimental data file is EXPLORE.DAT (verify here that the weather station is PHIL1.992 and that ETMOD = 'PENMAN'). Locate in CONTROL.DAT the name of the rerun file. Open the file RERUNS.DAT and note that this file is empty: all lines start with an * and are, therefore, ignored by ORYZA2000. Remove the * for all lines that define the start time of simulation (7 times) and run ORYZA2000. Remember that the emergence dates (EMD) will be the same as the start times (STTIME) since we make the simulations in the exploration mode (see Ex-I.12-I.15). Open OP.DAT and note the 8 sets of output: the first line is the original simulation run with STTIME=4., and the subsequent 7 lines define the outputs associated with STTIME=50., STTIME=100., etc. Compare your results with Table I.5. Verify that the first line is the same as the values in the column original of Table I.4. The last column in OP.DAT gives cumulative rainfall since transplanting (RAINCU), and we see how rainfall strongly varies throughout the year. Next, open RES.DAT and note the 8 sets of output data files, Run_0 till Run_7. Each set contains the detailed results of one rerun. Verify that each rerun was indeed executed with the correct STTIME. Next, open the graphics window and select total above-ground biomass (WAGT) on the Y-axis and TIME on the X-axis. Then, open option Runs next to the option Axes, and select all 8 runs. Now produce the graph.
Table I.5.
Figure I.3. Simulated above-ground biomass (kg ha-1) versus time, for eight runs with different start times/emergence dates.
Ex-I.51. Edit the file RERUNS.DAT so that the contents read:
* rerun set 1
SBDUR = 14
NH = 10.
* rerun set 2
SBDUR = 20
NH = 15.
We now have defined two reruns, in each of which two parameter values change at the same time. Run ORYZA2000 and study OP.DAT (compare with Table I.6), RES.DAT and make some graphs. Next, we want to make the second rerun with the same number of hills (NH) as the first rerun. But each variable that is redefined in the first rerun set should also be redefined in the second, even if you want to retain the same value. The correct file for this exercise should therefore read:
SBDUR = 14
NH = 10.
* rerun set 2
SBDUR = 20
NH = 10.
Run the model again and examine the results; compare with Table I.7.
Table I.6.
Table I.7.
Ex-I.52. Delete the contents of the file RERUNS.DAT and run the model. Verify whether there is only one run now.
In this course, extensive use will be made of the rerun option and various other uses of RERUNS.DAT will be demonstrated.
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