Optimize one edge-isometric repulsive unfolding stage
Source:R/gmds_edge_repulsive_unfolding.R
edge.repulsive.stage.Rd`edge.repulsive.stage()` performs one gradient-descent stage for the objective evaluated by `edge.repulsive.state()`. It uses Armijo backtracking, optionally recenters coordinates after each proposal, and returns the final coordinates plus a per-iteration trace.
Usage
edge.repulsive.stage(
coords,
edges,
edge.lengths,
edge.weights = NULL,
lambda = 0,
edge.family = c("quadratic", "upper_barrier"),
eps.plus = 0.35,
beta = 0,
pair.index = NULL,
pair.weights = NULL,
repulsion.family = c("log", "inverse_power"),
repulsion.delta = 0.001,
repulsion.power = 1,
max.iter = 80L,
initial.step = 0.02,
step.shrink = 0.5,
armijo = 1e-04,
min.step = 1e-08,
grad.tol = 1e-07,
recenter = TRUE,
distance.eps = 1e-10,
return.frames = FALSE,
engine = c("cpp", "R")
)Arguments
- coords
Numeric `n` by `dim` coordinate matrix.
- edges
Integer or numeric matrix with two columns containing 1-based graph edge endpoints.
- edge.lengths
Numeric vector of target edge lengths, parallel to `edges`.
- edge.weights
Optional non-negative edge weights. Defaults to one.
- lambda
Repulsion strength.
- edge.family
Edge potential family, either `"quadratic"` or `"upper_barrier"`.
- eps.plus
Upper-barrier slack parameter.
- beta
Upper-barrier strength. When `beta <= 0`, the edge potential is quadratic.
- pair.index
Optional two-column matrix of 1-based vertex pairs for the repulsion term. If `NULL` and `lambda > 0`, all unordered pairs are used.
- pair.weights
Optional pair weights, parallel to `pair.index`.
- repulsion.family
Repulsion potential family, either `"log"` or `"inverse_power"`.
- repulsion.delta
Small positive softening parameter for pair distances.
- repulsion.power
Power used by the `"inverse_power"` repulsion.
- max.iter
Maximum number of gradient-descent iterations.
- initial.step
Initial gradient step size.
- step.shrink
Multiplicative shrink factor used by backtracking.
- armijo
Armijo sufficient-decrease coefficient.
- min.step
Minimum allowable step before the stage stops.
- grad.tol
Gradient-norm stopping tolerance.
- recenter
Logical; whether to recenter coordinates after each proposal.
- distance.eps
Small positive distance floor used in derivatives.
- return.frames
Logical; whether to return accepted coordinate frames. Frame 0 is the starting coordinate matrix and later frames are accepted updates.
- engine
Backend engine. `"cpp"` is the default; `"R"` uses the reference implementation.