Get Positions of a Specific Occurrence State Transition Within Candidate Indices

Returns the positions within `day0_idx` where a specified state transition occurs, based on wet/dry/extreme day thresholds.

Usage

match_transition_positions(
  state_from,
  state_to,
  precip_vec,
  day0_idx,
  wet_threshold,
  extreme_threshold
)

Arguments

state_from

Integer. The current occurrence state (0 = dry, 1 = wet, 2 = extreme).

state_to

Integer. The next occurrence state (0 = dry, 1 = wet, 2 = extreme).

precip_vec

Numeric vector of precipitation values.

day0_idx

Integer vector of indices representing candidate "day 0" positions in the time series.

wet_threshold

Numeric. Threshold separating dry and wet days.

extreme_threshold

Numeric. Threshold above which days are considered extreme.

Value

Integer vector of positions within `day0_idx` where the transition from `state_from` to `state_to` occurs.

Details

Occurrence states are defined as: - 0: Dry day (precipitation <= wet_threshold) - 1: Wet day (precipitation > wet_threshold and <= extreme_threshold) - 2: Extreme wet day (precipitation > extreme_threshold)

Examples

precip_vec <- c(0, 0, 5, 15, 30, 0, 2, 25, 40, 0)
day0_idx <- 1:(length(precip_vec) - 1)
wet_threshold <- 1
extreme_threshold <- 20

match_transition_positions(0, 1, precip_vec, day0_idx, wet_threshold, extreme_threshold)
#> [1] 2 6
match_transition_positions(1, 2, precip_vec, day0_idx, wet_threshold, extreme_threshold)
#> [1] 4 7
match_transition_positions(2, 0, precip_vec, day0_idx, wet_threshold, extreme_threshold)
#> [1] 5 9