Simulating singular matrix error in SEMinR

seminr_singular_error_test.R

library(seminr)

comp1_items <- multi_items("IMAG", 1:5)
comp2_items <- multi_items("CUEX", 1:3)
comp3_items <- multi_items("CUSA", 1:3)

mobi_mm <- constructs(
  # Three first-order composites
  composite("Comp1",        comp1_items),
  composite("Comp2",        comp2_items),
  composite("Comp3",        comp3_items),

  # First-order representation of higher-order composite (repeated indicators)
  composite("Comp_1_2",     c(comp1_items, comp2_items)),

  # Second-order composite of two composites
  higher_composite("HOC_1_2", c("Comp1", "Comp2"))
)


# HAPPY: no duplicate constructs
happy_sm_lower <- relationships(
  paths(from="Comp3", to="Comp1"),
  paths(from="Comp3", to="Comp2")
)

happy_pls_lower <- estimate_pls(mobi, mobi_mm, happy_sm_lower)
summary(happy_pls_lower)
# Path Coefficients:
#        Comp1 Comp2
# R^2    0.484 0.266
# AdjR^2 0.482 0.263
# Comp3  0.695 0.516


# SAD: duplicate endogenous constructs
sad_sm_lower <- relationships(
  paths(from="Comp3", to="Comp1"),
  paths(from="Comp3", to="Comp1")
)

sad_pls_lower <- estimate_pls(mobi, mobi_mm, sad_sm_lower)
# Error: Lapack routine dgesv: system is exactly singular: U[2,2] = 0
# [Traceback]: inner_paths[independant,dependant[i]] = solve(t(construct_scores[,independant]) %*% construct_scores[,independant], t(construct_scores[,independant]) %*% construct_scores[,dependant[i]])


# SAD: duplicate construct in higher-order
sad_sm_higher <- relationships(
  paths(from="Comp3", to="Comp1"),
  paths(from="Comp3", to="HOC_1_2")
)

sad_pls_higher <- estimate_pls(mobi, mobi_mm, sad_sm_higher)
# Error: Lapack routine dgesv: system is exactly singular: U[2,2] = 0
# [Traceback]: inner_paths[independant,dependant[i]] = solve(t(construct_scores[,independant]) %*% construct_scores[,independant], t(construct_scores[,independant]) %*% construct_scores[,dependant[i]])


# HAPPY: Duplicate items in constructs, but repeated indicators HOC
happy_sm_compcomp <- relationships(
  paths(from="Comp3", to="Comp1"),
  paths(from="Comp3", to="CompComp")
)

happy_pls_compcomp <- estimate_pls(mobi, mobi_mm, happy_sm_compcomp)
summary(happy_pls_compcomp)
# Path Coefficients:
#        Comp1 CompComp
# R^2    0.485    0.519
# AdjR^2 0.482    0.517
# Comp3  0.696    0.720