Running and Saving Simulations

Simulation Mode: Manual vs. Auto-Run

music can be run in two modes: Auto Run or Manual. To switch between modes, go to the 'Settings' tabs and set Auto Run Models to on (green) or off (red). In Auto Run mode, music will automatically re-run the simulation, any time a change is made to the Catchment (for example, a new Node is added, or the properties of a Source Node or Treatment Node are changed). This allows you to see the results of your changes instantly, but it can be very time-consuming, particularly for complex simulations over long durations.

In manual mode (Auto Run turned off), click the Run Catchment Models Button ( or press F5) to run the simulation, when required.

music starts automatically in manual mode (Auto Run turned off). Whether you wish to leave Auto Run turned off depends on the complexity, time-step and duration of simulation you are running, your computer’s speed, and your need to see the results of changes ‘on the fly’.

The following table summarises the advantages and disadvantages of running music in Auto Run or Manual mode.

	Manual (Auto Run OFF)	Automatic (Auto Run ON)
Advantages	Faster operation, particularly for Catchments with many nodes, small time-steps, or long durations Smooth and efficient construction of model	Immediate simulation of nodes creation or modification ‘on the fly’ Automatic updating of output screens (graphs, statistics tables, etc) when a node is modified Detection of ‘mistakes’ more likely (results immediately shown) Allows informal ‘what if?’ playing
Disadvantages	Results of modifications to the catchment file (such as modifying the specifications of a treatment node) are not immediately visible Output display (graphs and statistics tables) will disappear if modifications to the catchment are made (since results of the previous simulation no longer apply) Mistakes made in specifying node parameters may be more difficult to identify	Operation will be slower and less efficient, particularly for complex models with many nodes, small time-steps, and a long duration

Tip Box

In most cases (except for very simple simulations), it is recommended that you construct your simulation with Auto Run turned OFF, and manually run the simulation when required.

Running music from the Command Line

In addition to using the graphical user interface, you can use the command line mode to run music. A major advantage of this is that it allows you to run music in batch mode, or use it with other third-party tools (for example, optimisation software such as eWater Insight).

You can perform several actions in music using the command line including:

Specifying various files to use, such as the input data files, music project files, climate template files and configuration files;

Obtain the output files for several parameters such as:

oTime series;

oMean annual loads;

oTreatment train effectiveness;

oNode water balance;

oLife cycle cost; and

oStatistics.

Specifying the output file type. For example, choose a flux file or time series output.

Note that any errors occurring during execution are written to a log file.

For more information on using the command line, contact eWater support.

Saving music files

Whenever you run a simulation, music will prompt you to save the file; it is a good idea to do so, to reduce the risk of losing the model in the event of a system hang.

music has two primary file types:

music data files (.sqz): saves model setup (and its attached meteorological template), but not simulation results - file size generally < 500kb; and

music data files with results (.sqr): saves the full model setup and all simulation results - file size may be very large, depending on model complexity, time-step and period of meteorological template.

It is generally advisable to save .sqz files (to save disk space), but the model will need to be re-run upon opening (this takes no longer, and often less time, than opening the full file with all simulation results).

However, in some instances, you may wish to save the simulation with all attached results, so that the exact simulation is preserved when you next open (particularly where you are using stochastic simulation of pollutant time-series, when results from subsequent simulations may vary slightly).

music can import and/or open files created by earlier versions of music, BUT if you want to open them again using an earlier version of music, you must use "Save As" to save them with a different name (leaving the original file unchanged).

Tip Box

Use the "Save As" function to save old music Version 3 or earlier files with a different name, so that the original files can be opened again in music Version 3 or earlier, if required.