Vector migration files#

Vector migration file describes the rate of migration of vectors out of a geographic node analogously to human migration (see Migration files for more information), although vector migration supports gender parameters, it does not support migration by age and age-based migration in the migration file will cause an error. Vector migration is one way, such that each trip made by a vector is independent of previous trips made by the vector. For Vector_Sampling_Type set to “TRACK_ALL_VECTORS” or “SAMPLE_IND_VECTORS”, the rates in the file are used to control whether or not a female vector will migrate: the rate specified is used to get a “time to leave on trip” value from an exponential distribution. If the value is less than one day, then the female vector will migrate. For male vectors (who are always in cohorts/compartments), and for female vectors when Vector_Sampling_Type is set to “VECTOR_COMPARTMENTS_NUMBER” or “VECTOR_COMPARTMENTS_PERCENT”, the rates in the file are used to calculate what fraction of the population is traveling out of the node on that day based on a total rate of travel out of that node and the traveling vectors are distributed to their destination nodes in proportion of rates to those nodes to the total outbound rate.

If default geography is used (the configuration parameter Enable_Demographics_Builtin is set to 1, and Default_Geography_Initial_Node_Population and Default_Geography_Torus_Size are configured), vector migration will be built internally and vectors will automatically migrate. It is a known issue, please see InstituteforDiseaseModeling/EMOD#43

Vectors “LOCAL_MIGRATION” MigrationType for all their migration needs, but are not limited to the default maximum data values of 8 (destinations).

Each vector species has its own Vector_Migration_Filename, if it is left as an empty string, no migration will happen for that species. The Vector_Migration_Modifier_Equation and its parameters can influence female vector migration to particular nodes over others, while x_Vector_Migration is a multiplier affects the migration rates for both genders. See Configuration parameters for more information on the parameters governing vector migration.

Migration Files#

Vectors use the same migration files as humans, with two caveats:

  1. Vectors do not migrate by-age, so multiple AgeBins in the by-age by-gender migration file will cause an error.

  2. Vector migration only uses MigrationType “LOCAL_MIGRATION” all other migration types will cause an error.