Table 1.

List of abbreviations for regularization parameter selection methods. To indicate the use of unconstrained P(r) in a method, the suffix ‘u’ is appended to the abbreviation. If a tuning parameter is used, its value is appended as well.

Acronym	Full name
AIC	Akaike information criterion
AICC	corrected Akaike information criterion
BIC	Bayesian information criterion
BP	balancing principle
CV	leave-one-out cross validation
DP	discrepancy principle
EE	extrapolated error
GCV	generalized cross validation
GML	generalized maximum-likelihood
hBP	hardened balancing principle
ICOMP	information complexity criterion
LC	L-curve, maximum curvature
LR	L-curve, minimum radius
LR2	L-curve, minimum radius 2
MCL	Mallows’ CL
mGCV	modified generalized cross validation
NCP	normalized cumulative periodogram
QO	quasi-optimality criterion
rGCV	robust generalized cross validation
RM	residual method
SC	self-consistency method
srGCV	strong robust generalized cross validation
tDP	transformed discrepancy principle