rotations: Rotations

In GPArotation: Gradient Projection Factor Rotation

Rotations

Description

Optimize factor loading rotation objective.

Usage

    oblimin(A, Tmat=diag(ncol(A)), gam=0, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    quartimin(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    targetT(A, Tmat=diag(ncol(A)), Target=NULL, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0, L=NULL)
    targetQ(A, Tmat=diag(ncol(A)), Target=NULL, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0, L=NULL)
    pstT(A, Tmat=diag(ncol(A)), W=NULL, Target=NULL, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0, L=NULL)
    pstQ(A, Tmat=diag(ncol(A)), W=NULL, Target=NULL, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0, L=NULL)
    oblimax(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    entropy(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    quartimax(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5,maxit=1000,randomStarts=0)
    Varimax(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    simplimax(A, Tmat=diag(ncol(A)), k=nrow(A), normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    bentlerT(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    bentlerQ(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    tandemI(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    tandemII(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    geominT(A, Tmat=diag(ncol(A)), delta=.01, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    geominQ(A, Tmat=diag(ncol(A)), delta=.01, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    bigeominT(A, Tmat=diag(ncol(A)), delta=.01, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    bigeominQ(A, Tmat=diag(ncol(A)), delta=.01, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    cfT(A, Tmat=diag(ncol(A)), kappa=0, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    cfQ(A, Tmat=diag(ncol(A)), kappa=0, normalize=FALSE, eps=1e-5, 
    		maxit=1000, randomStarts=0)
    equamax(A, Tmat=diag(ncol(A)), kappa=ncol(A)/(2*nrow(A)), normalize=FALSE,
    		eps=1e-5, maxit=1000, randomStarts = 0)
    parsimax(A, Tmat=diag(ncol(A)), kappa=(ncol(A)-1)/(ncol(A)+nrow(A)-2), 
    		normalize=FALSE, eps=1e-5, maxit=1000, randomStarts = 0)
    infomaxT(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    infomaxQ(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    mccammon(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    varimin(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000, randomStarts=0)
    bifactorT(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000,randomStarts=0)
    bifactorQ(A, Tmat=diag(ncol(A)), normalize=FALSE, eps=1e-5, maxit=1000,randomStarts=0)
    

Arguments

A	an initial loadings matrix to be rotated.
Tmat	initial rotation matrix.
gam	0=Quartimin, .5=Biquartimin, 1=Covarimin.
Target	rotation target for objective calculation.
W	weighting of each element in target.
k	number of close to zero loadings.
delta	constant added to Lambda^2 in objective calculation.
kappa	see details.
normalize	parameter passed to optimization routine (GPForth or GPFoblq).
eps	parameter passed to optimization routine (GPForth or GPFoblq).
maxit	parameter passed to optimization routine (GPForth or GPFoblq).
randomStarts	parameter passed to optimization routine (GPFRSorth or GPFRSoblq).
L	provided for backward compatibility in target rotations only. Use A going forward.

Details

These functions optimize a rotation objective. They can be used directly or the function name can be passed to factor analysis functions like factanal. Several of the function names end in T or Q, which indicates if they are orthogonal or oblique rotations (using GPFRSorth or GPFRSoblq respectively).

Rotations which are available are

oblimin	oblique	oblimin family
quartimin	oblique
targetT	orthogonal	target rotation
targetQ	oblique	target rotation
pstT	orthogonal	partially specified target rotation
pstQ	oblique	partially specified target rotation
oblimax	oblique
entropy	orthogonal	minimum entropy
quartimax	orthogonal
varimax	orthogonal
simplimax	oblique
bentlerT	orthogonal	Bentler's invariant pattern simplicity criterion
bentlerQ	oblique	Bentler's invariant pattern simplicity criterion
tandemI	orthogonal	Tandem principle I criterion
tandemII	orthogonal	Tandem principle II criterion
geominT	orthogonal
geominQ	oblique
bigeominT	orthogonal
bigeominQ	oblique
cfT	orthogonal	Crawford-Ferguson family
cfQ	oblique	Crawford-Ferguson family
equamax	orthogonal	Crawford-Ferguson family
parsimax	orthogonal	Crawford-Ferguson family
infomaxT	orthogonal
infomaxQ	oblique
mccammon	orthogonal	McCammon minimum entropy ratio
varimin	orthogonal
bifactorT	orthogonal	Jennrich and Bentler bifactor rotation
bifactorQ	oblique	Jennrich and Bentler biquartimin rotation

Note that Varimax defined here uses vgQ.varimax and is not varimax defined in the stats package. stats:::varimax does Kaiser normalization by default whereas Varimax defined here does not.

The argument kappa parameterizes the family for the Crawford-Ferguson method. If m is the number of factors and p is the number of indicators then kappa values having special names are 0=Quartimax, 1/p=Varimax, m/(2*p)=Equamax, (m-1)/(p+m-2)=Parsimax, 1=Factor parsimony.

Value

A list (which includes elements used by factanal) with:

loadings	Lh from GPFRSorth or GPFRSoblq.
Th	Th from GPFRSorth or GPFRSoblq.
Table	Table from GPForth or GPFoblq.
method	A string indicating the rotation objective function.
orthogonal	A logical indicating if the rotation is orthogonal.
convergence	Convergence indicator from GPFRSorth or GPFRSoblq.
Phi	t(Th) %*% Th. The covariance matrix of the rotated factors. This will be the identity matrix for orthogonal rotations so is omitted (NULL) for the result from GPFRSorth and GPForth.
randStartChar	Vector indicating results from random starts from GPFRSorth or GPFRSoblq

Author(s)

Coen A. Bernaards and Robert I. Jennrich with some R modifications by Paul Gilbert.

References

Bernaards, C.A. and Jennrich, R.I. (2005) Gradient Projection Algorithms and Software for Arbitrary Rotation Criteria in Factor Analysis. Educational and Psychological Measurement, 65, 676–696.

Bifactor rotation, bifactorT and bifactorQ are called bifactor and biquartimin in Jennrich, R.I. and Bentler, P.M. (2011) Exploratory bi-factor analysis. Psychometrika, 76.

See Also

GPFRSorth, GPFRSoblq, vgQ, eiv, echelon, WansbeekMeijer, factanal, varimax

Examples

  # see GPFRSorth and GPFRSoblq for more examples
  
  # getting loadings matrices
  data("Harman", package="GPArotation")
  qHarman  <- GPFRSorth(Harman8, Tmat=diag(2), method="quartimax")
  qHarman <- quartimax(Harman8) 
  loadings(qHarman) - qHarman$loadings   #2 ways to get the loadings

  # factanal loadings used in GPArotation
  data("WansbeekMeijer", package="GPArotation")
  fa.unrotated  <- factanal(factors = 2, covmat=NetherlandsTV, normalize=TRUE, rotation="none")
  quartimax(loadings(fa.unrotated), normalize=TRUE)
  geominQ(loadings(fa.unrotated), normalize=TRUE, randomStarts=100)

  # passing arguments to factanal (See vignette for a caution)
  # vignette("GPAguide", package = "GPArotation")
  data(ability.cov)
  factanal(factors = 2, covmat = ability.cov, rotation="infomaxT")
  factanal(factors = 2, covmat = ability.cov, rotation="infomaxT", 
    control=list(rotate=list(normalize = TRUE, eps = 1e-6)))
  # when using factanal for oblique rotation it is best to use the rotation command directly
  # instead of including it in the factanal command (see Vignette).  
  fa.unrotated  <- factanal(factors = 3, covmat=NetherlandsTV, normalize=TRUE, rotation="none")
  quartimin(loadings(fa.unrotated), normalize=TRUE)

  # oblique target rotation of 2 varimax rotated matrices towards each other
  # See vignette for additional context and computation,
  trBritain <- matrix( c(.783,-.163,.811,.202,.724,.209,.850,.064,
    -.031,.592,-.028,.723,.388,.434,.141,.808,.215,.709), byrow=TRUE, ncol=2)
  trGermany <- matrix( c(.778,-.066, .875,.081, .751,.079, .739,.092,
    .195,.574, -.030,.807, -.135,.717, .125,.738, .060,.691), byrow=TRUE, ncol = 2)
  trx <- targetQ(trGermany, Target = trBritain)
  # Difference between rotated loadings matrix and target matrix 
  y <- trx$loadings - trBritain
  
  # partially specified target; See vignette for additional method
  A <- matrix(c(.664, .688, .492, .837, .705, .82, .661, .457, .765, .322, 
    .248, .304, -0.291, -0.314, -0.377, .397, .294, .428, -0.075,.192,.224,
    .037, .155,-.104,.077,-.488,.009), ncol=3)  
  SPA <- matrix(c(rep(NA, 6), .7,.0,.7, rep(0,3), rep(NA, 7), 0,0, NA, 0, rep(NA, 4)), ncol=3)
  targetT(A, Target=SPA)

  # using random starts
  data("WansbeekMeijer", package="GPArotation")
  fa.unrotated  <- factanal(factors = 3, covmat=NetherlandsTV, normalize=TRUE, rotation="none")
  # single rotation with a random start
  oblimin(loadings(fa.unrotated), Tmat=Random.Start(3))
  oblimin(loadings(fa.unrotated), randomStarts=1)
  # multiple random starts
  oblimin(loadings(fa.unrotated), randomStarts=100)

  # assessing local minima for box26 data
  data(Thurstone, package = "GPArotation")
  infomaxQ(box26, normalize = TRUE, randomStarts = 150)
  geominQ(box26, normalize = TRUE, randomStarts = 150)
  # for detailed investigation of local minima, consult package 'fungible' 
  # library(fungible)
  # faMain(urLoadings=box26, rotate="geominQ", rotateControl=list(numberStarts=150))
  # library(psych) # package 'psych' with random starts:
  # faRotations(box26, rotate = "geominQ", hyper = 0.15, n.rotations = 150)

  

GPArotation documentation built on May 29, 2024, 8:16 a.m.