{"data":{"markdownRemark":{"html":"

Loading Data

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This part will get you started with populating models using data.

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Loading agents from data

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Let's take a simplified version of the agent class City and let's say you have the following kind of data where each City has:

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More precisely the data is organised like so:

\n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n
idnamepopulationsurface
23323443Kodiak783 90420 229
48217039Firebrick13 0034320
37410058Onalaska2 377 84361 839
93749281Ak-Chin Village453 15017 323
55283047Blacktail1 921 61349 315
............
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Here, there is an additional field called id (which is a unique number) that identifies each record.

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On the type of data supported

\nThe Simudyne SDK supports consistent schema of data : the records present in your data should not be duplicated and there must exist a field that identifies each individual record.\n

Each record will be mapped to an agent, and each field of a record, except the indexing field (that is defaulted to id), will be mapped to the eponymous agent attribute.

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Hence, if your data does not have a field identifying each of your record, you should add a new id column to your dataset to use.

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We can come up with a simplified version of the Agent class City described above to match this data:

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\n \n \n \n \n \n \n \n \n \n \n \n \n \n

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To import data, you have to annotate your fields like so so that records in your data can be mapped to Cities.

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Class definition (Java)

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class City extends Agent {\n  @Constant\n  String name;\n\n  @Constant\n  int population;\n\n  @Constant\n  float surface;\n\n  //...\n}
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Finally, to import your agents in your model, you have to use the system loadGroup() method.

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You have to specify a Source to use ; this object is dedicated to import data from your file or data base. Let's use a CSVSource to import the data from a CSV file !

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Is there only Source for CSV (CSVSource) out there ?

\nIn our example we suppose the data is stored in a CSV so we use a CSVSource to trigger it. However, you can use other Source -- like JDBCSource -- to import data from other data storage. Check the dedicated section in the following.\n
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Windows user

The `/` in the paths needs to be replaced with `\\`.
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Creating data group (Java)

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// Creating a Source to import data -- you can use another type of source too\nCSVSource citySource = new CSVSource(\"/path/to/myCities.csv\");\n\nGroup<City> cities = loadGroup(City.class, citySource);
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And now, all the Cities contains as records in your data are imported into your model !

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On IDs present in data vs IDs used in the AgentBasedModel

\nThe IDs present in the AgentBasedModel when importing data are not used any more as data gets remapped to agent that are given a new ID adapted to the state of the system.\n

Thus, IDs present in your data still remain important as they identify agents; but won't be used in the system once the records are imported.

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What if I do not have enough of fields for the agent that I want to model ?

\nIf you do not have enough fields in your dataset compared to what you would like to have in your model for an agent class, this is not restrictive to use data import. The fields present into your data will be mapped to some of the fields of your agents, leaving the remaining ones with their default values.\n
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Let's now imagine that you want to introduce Roads between your Cities.

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\n \n \n \n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n
idnamepopulationsurface
23323443Kodiak78390420229
48217039Firebrick130034320
37410058Onalaska237784361839
93749281Ak-Chin Village45315017323
55283047Blacktail192161349315
............
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... and that you have another a data sets of Roads linking Cities together:

\n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n
fromtolength
233234434821703923.32
3741005823323443343.3
233234435528304743.13
552830479374928133.38
.........
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Here, from and to identify respectively the source agents and the target agents.

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The remaining fields will be injected in the link at their creation. In our context, there is just one remaining field, length, that represent the length of a Road from the City identified by the ID from to the City identified by the ID to.

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You can import those links in your model and between your two groups using the connect() with a 'Source'.

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Connecting a Group Using Data (Java)

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CSVSource citySource = new CSVSource(\"/path/to/myCities.csv\");\nCSVSource roadSource = new CSVSource(\"/path/to/myRoads.csv\");\n\nGroup<City> cities = loadGroup(City.class, citySource);\n\ncities.loadConnections(cities, Road.class, roadSource);
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You can also connect two different Groups as well:

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Connect two Groups using Data

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CSVSource citySource = new CSVSource(\"/path/to/myCities.csv\");\nCSVSource countrySource = new CSVSource(\"/path/to/myCountry.csv\");\n\nCSVSource linkSource = new CSVSource(\"/path/to/myLinks.csv\");\n\nGroup<City> cities = loadGroup(City.class, citySource);\nGroup<Country> countries = loadGroup(Country.class, countrySource);\n\ncities.loadConnections(countries, MyLink.class, linkSource);
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More about Sources

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If you have data you want to import from a database, you can use a JDBCSource that supports MySQL, SQLite as well as PostGreSQL. Here is an example for SQLite:

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Using JDBC Sources (java)

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String connectionString = s\"jdbc:sqlite:path/to/myDataBase.db\";\n\nJDBCSource citySource = new JDBCSource(connectionString, \"Country\", \"username\", \"password\");
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Java JDBC connection string examples

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How about supporting other Sources ?

\nFor now, Source have been implemented for CSV files and relational databases. In the future, more solutions will be covered, especially non-relational databases a la NoSQL.\n
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