`repulsive.state()` evaluates only the repulsion term used by the experimental GMDS repulsive-unfolding operators. Unlike [edge.repulsive.state()], this function has no graph-edge term and does not require placeholder edges or edge lengths.
repulsive.state(
coords,
lambda = 1,
pair.index = NULL,
pair.weights = NULL,
repulsion.family = c("log", "inverse_power"),
repulsion.delta = 0.001,
repulsion.power = 1,
distance.eps = 1e-10,
engine = c("cpp", "R")
)A list containing energy, unscaled repulsion energy, gradient, gradient norm, and embedded pair lengths.
Numeric `n` by `dim` coordinate matrix.
Repulsion strength. The returned total energy is `lambda * repel.energy`; the gradient is scaled by `lambda`.
Optional two-column matrix of 1-based vertex pairs. If `NULL` and `lambda > 0`, all unordered pairs are used.
Optional non-negative pair weights parallel to `pair.index`.
Repulsion potential family, either `"log"` or `"inverse_power"`.
Small positive softening parameter for pair distances.
Power used by the `"inverse_power"` repulsion.
Small positive distance floor used in derivatives.
Backend engine. `"cpp"` is the default; `"R"` uses the reference implementation.