# install.packages("dodgr")  # run once if needed
library(dodgr)

# --- 1. Perfect full binary tree, 3 levels, with extra upstream node X ------
#              X
#              |
#              A
#            /   \
#           B     C
#          / \   / \
#         D   E F   G
#
# Edges: parent -> child

graph <- data.frame(
  edge_id  = 1:7,
  from     = c("X", "A","A",  "B","B",  "C","C"),
  to       = c("A", "B","C",  "D","E",  "F","G"),
  weight   = rep(1, 7),   # routing weight
  distance = rep(1, 7)    # distance metric
)

# --- 2. OD pairs with flows at the LEAVES -----------------------------------
# Origin:      the new upstream node "X"
# Destinations: the four leaves "D", "E", "F", "G"
from  <- "X"
to    <- c("D", "E", "F", "G")

# Flows matrix: nrow = length(from) = 1, ncol = length(to) = 4
# X->D = 5, X->E = 5, X->F = 10, X->G = 10
flows <- matrix(c(5, 5, 10, 10), nrow = length(from))

# --- 3. Aggregate flows along shortest paths --------------------------------
agg <- dodgr_flows_aggregate(
  graph    = graph,
  from     = from,
  to       = to,
  flows    = flows,
  contract = FALSE,   # avoid small-graph contraction issues
  norm_sums = FALSE   # <-- KEY CHANGE
)

# --- 4. Inspect results ------------------------------------------------------
# Show only edges with non-zero flow
agg[agg$flow > 0, ]

# The flow between X and A is simply the 'flow' value on edge X -> A,
# which will be the sum of all leaf flows: 5 + 5 + 10 + 10 = 30.