This brick encapsulates a chain of interleaved resources, i.e., the current resource is not released until the next one in the chain is available. An interesting property of such a pattern is that, if one resource is blocked for some reason, the whole chain stops.
Arguments
- .trj
the trajectory object.
- resources
character vector of resource names.
- task
the timeout duration supplied by either passing a numeric or a callable object (a function) which must return a numeric (negative values are automatically coerced to positive).
- amount
the amount to seize/release, accepts either a numeric or a callable object (a function) which must return a numeric.
Value
Returns the following chain of activities: seize
(1) > timeout > [seize (token to 2)
> release (1) > seize (2) >
timeout > release (2) >
release (token to 2) > ... (repeat) ]
(see examples below). Thus, the total number of activities appended is
length(resources) * 3 + (length(resources)-1) * 2.
Details
Both task and amount accept a list of values/functions,
instead of a single one, that should be of the same length as resources,
so that each value/function is applied to the resource of the same index.
The transition to the second and subsequent resources is guarded by a token,
an auxiliary resource whose capacity must be equal to the capacity + queue
size of the guarded resource, and its queue size must be infinite. For example,
if two resources are provided, c("A", "B"), the auxiliary resource will
be named "B_token". If capacity=2 and queue_size=1 for B,
then capacity=3 and queue_size=Inf must be the values for
B_token. But note that the user is responsible for adding such an auxiliary
resource to the simulation environment with the appropriate parameters.
Examples
## These are equivalent:
trajectory() %>%
interleave(c("A", "B"), c(2, 10), 1)
#> trajectory: anonymous, 8 activities
#> { Activity: Seize | resource: A, amount: 1 }
#> { Activity: Timeout | delay: 2 }
#> { Activity: Seize | resource: B_token, amount: 1 }
#> { Activity: Release | resource: A, amount: 1 }
#> { Activity: Seize | resource: B, amount: 1 }
#> { Activity: Timeout | delay: 10 }
#> { Activity: Release | resource: B, amount: 1 }
#> { Activity: Release | resource: B_token, amount: 1 }
trajectory() %>%
seize("A", 1) %>%
timeout(2) %>%
seize("B_token", 1) %>%
release("A", 1) %>%
seize("B", 1) %>%
timeout(10) %>%
release("B", 1) %>%
release("B_token", 1)
#> trajectory: anonymous, 8 activities
#> { Activity: Seize | resource: A, amount: 1 }
#> { Activity: Timeout | delay: 2 }
#> { Activity: Seize | resource: B_token, amount: 1 }
#> { Activity: Release | resource: A, amount: 1 }
#> { Activity: Seize | resource: B, amount: 1 }
#> { Activity: Timeout | delay: 10 }
#> { Activity: Release | resource: B, amount: 1 }
#> { Activity: Release | resource: B_token, amount: 1 }