Conduct log-ratio lasso regression for continuous, binary and survival outcomes.
Usage
FLORAL(
x,
y,
ncov = 0,
family = "gaussian",
longitudinal = FALSE,
id = NULL,
tobs = NULL,
failcode = NULL,
length.lambda = 100,
lambda.min.ratio = NULL,
ncov.lambda.weight = 0,
a = 1,
mu = 1,
ncv = 5,
ncore = 1,
intercept = FALSE,
foldid = NULL,
step2 = TRUE,
progress = TRUE,
plot = TRUE
)
Arguments
- x
Feature matrix, where rows specify subjects and columns specify features. The first
ncov
columns should be patient characteristics and the rest columns are microbiome absolute counts corresponding to various taxa. Ifx
contains longitudinal data, the rows must be sorted in the same order of the subject IDs used iny
.- y
Outcome. For a continuous or binary outcome,
y
is a vector. For survival outcome,y
is aSurv
object.- ncov
An integer indicating the number of first
ncov
columns inx
that will not be subject to the zero-sum constraint.- family
Available options are
gaussian
,binomial
,cox
,finegray
.- longitudinal
TRUE
orFALSE
, indicating whether longitudinal data matrix is specified for inputx
. (Still under development. Please use with caution)- id
If
longitudinal
isTRUE
,id
specifies subject IDs corresponding to the rows of inputx
.- tobs
If
longitudinal
isTRUE
,tobs
specifies time points corresponding to the rows of inputx
.- failcode
If
family = finegray
,failcode
specifies the failure type of interest. This must be a positive integer.- length.lambda
Number of penalty parameters used in the path
- lambda.min.ratio
Ratio between the minimum and maximum choice of lambda. Default is
NULL
, where the ratio is chosen as 1e-2.- ncov.lambda.weight
Weight of the penalty lambda applied to the first
ncov
covariates. Default is 0 such that the firstncov
covariates are not penalized.- a
A scalar between 0 and 1:
a
is the weight for lasso penalty while1-a
is the weight for ridge penalty.- mu
Value of penalty for the augmented Lagrangian
- ncv
Folds of cross-validation. Use
NULL
if cross-validation is not wanted.- ncore
Number of cores for parallel computing for cross-validation. Default is 1.
- intercept
TRUE
orFALSE
, indicating whether an intercept should be estimated.- foldid
A vector of fold indicator. Default is
NULL
.- step2
TRUE
orFALSE
, indicating whether a second-stage feature selection for specific ratios should be performed for the features selected by the main lasso algorithm. Will only be performed if cross validation is enabled.- progress
TRUE
orFALSE
, indicating whether printing progress bar as the algorithm runs.- plot
TRUE
orFALSE
, indicating whether returning plots of model fitting.
Value
A list with path-specific estimates (beta), path (lambda), and others. Details can be found in README.md
.
References
Fei T, Funnell T, Waters N, Raj SS et al. Scalable Log-ratio Lasso Regression Enhances Microbiome Feature Selection for Predictive Models. bioRxiv 2023.05.02.538599.
Examples
set.seed(23420)
# Continuous outcome
dat <- simu(n=50,p=30,model="linear")
fit <- FLORAL(dat$xcount,dat$y,family="gaussian",ncv=2,progress=FALSE,step2=TRUE)
# Binary outcome
# dat <- simu(n=50,p=30,model="binomial")
# fit <- FLORAL(dat$xcount,dat$y,family="binomial",progress=FALSE,step2=TRUE)
# Survival outcome
# dat <- simu(n=50,p=30,model="cox")
# fit <- FLORAL(dat$xcount,survival::Surv(dat$t,dat$d),family="cox",progress=FALSE,step2=TRUE)
# Competing risks outcome
# dat <- simu(n=50,p=30,model="finegray")
# fit <- FLORAL(dat$xcount,survival::Surv(dat$t,dat$d,type="mstate"),failcode=1,
# family="finegray",progress=FALSE,step2=FALSE)