Select the number of tensor synergies by a VAF threshold — muscleSynergyTensorOrder • PhysioEMG

Fits non-negative PARAFAC for increasing rank and returns the smallest number of synergies whose reconstruction VAF reaches vaf_threshold.

Usage

muscleSynergyTensorOrder(tensor, max_synergies = 6, vaf_threshold = 0.9, ...)

Arguments

tensor: A non-negative muscle x time x trial array.
max_synergies: Largest rank to try (default 6).
vaf_threshold: VAF target (default 0.90).
...: Passed to muscleSynergyTensor().

Value

A list with n_synergies (selected), vaf (per rank), and fit (the selected "synergy_tensor").

Examples

set.seed(1)
M <- 6; Tt <- 40; K <- 8; R <- 2
A0 <- matrix(runif(M * R), M, R); B0 <- matrix(runif(Tt * R), Tt, R)
C0 <- matrix(runif(K * R), K, R)
X <- array(0, c(M, Tt, K))
for (r in 1:R) for (k in 1:K) X[, , k] <- X[, , k] +
  (A0[, r] %o% B0[, r]) * C0[k, r]
ord <- muscleSynergyTensorOrder(X, max_synergies = 3, seed = 1)
ord$n_synergies
#> [1] 1