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contact_prob

Syntax

place <place-name> {
    contact_prob = <number>
    contact_prob_for_<condition_name> = <number>
}

network <network-name> {
    contact_prob = <number>
    contact_prob_for_<condition_name> = <number>
}

Description

Network and place property that sets the hourly rate at which agents contact each other in a given mixing group.

One of two contact modes in mixing groups; the other is contact_rate. In contact_prob, each transmissible agent has a fixed probability of contacts with any other agent within any given hour that the mixing group is in operation. In this mode, the total number of potential transmission contacts for a given condition in a mixing group during its open hours on a given day is given by the formula:

contacts = (hourly contact probability of group) * (number of members of the group - 1) * (number of transmissible agents) * (transmissibility of the condition) * (duration of the meeting in the group)

The contact_prob property specifies the contact probability per hour for all conditions.

If the contact_prob_for_<condition_name> property is present, it overrides the first property for the named condition.

The conversion from contact_rate to contact_prob for an equal number of contacts is:

contact_prob = contact_rate / (number of members of the place - 1)

The group agent for individual mixing groups can change the effective contact rate using the adjust_contacts action.

Examples

The contact rate of a Place such as households can be set at the start of the simulation with:

place Household {
    contact_prob = 0.3
}

See Also