R/coxph.R

Defines functions coxph

Documented in coxph

# Automatically generated from the noweb directory
#tt <- function(x) x
coxph <- function(formula, data, weights, subset, na.action,
        init, control, ties= c("efron", "breslow", "exact"),
        singular.ok =TRUE,  robust,
        model=FALSE, x=FALSE, y=TRUE,  tt, method=ties, 
        id, cluster, istate, statedata, nocenter=c(-1, 0, 1), ...) {

    ties <- match.arg(ties)
    Call <- match.call()
    ## We want to pass any ... args to coxph.control, but not pass things
    ##  like "dats=mydata" where someone just made a typo.  The use of ...
    ##  is simply to allow things like "eps=1e6" with easier typing
    extraArgs <- list(...)
    if (length(extraArgs)) {
        controlargs <- names(formals(coxph.control)) #legal arg names
        indx <- pmatch(names(extraArgs), controlargs, nomatch=0L)
        if (any(indx==0L))
            stop(gettextf("Argument %s not matched", 
                          names(extraArgs)[indx==0L]), domain = NA)
    }
    if (missing(control)) control <- coxph.control(...) 

    # Move any cluster() term out of the formula, and make it an argument
    #  instead.  This makes everything easier.  But, I can only do that with
    #  a local copy, doing otherwise messes up future use of update() on
    #  the model object for a user stuck in "+ cluster()" mode.
    if (missing(formula)) stop("a formula argument is required")
    
    ss <- c("cluster", "offset")
    if (is.list(formula))
        Terms <- if (missing(data)) terms(formula[[1]], specials=ss) else
                 terms(formula[[1]], specials=ss, data=data)
    else Terms <- if (missing(data)) terms(formula, specials=ss) else
                 terms(formula, specials=ss, data=data)

    tcl <- attr(Terms, 'specials')$cluster
    if (length(tcl) > 1) stop("a formula cannot have multiple cluster terms")

    if (length(tcl) > 0) { # there is one
        # subscripting of formulas is broken at least through R 3.5, if the
        #  formula contains an offset.  Adding offset to the "specials" above
        #  is just a sneaky way to find out if one is present, then call
        #  reformulate ourselves.  tt is a correct index into the row labels
        #  of the factors attribute, tt+1 to the variables attribute (which is
        #  a list, so you have to skip the "list" call).  The term.labels attr
        #  contains neither the response nor the offset, but does contain the
        #  interactions, which we need.  
        factors <- attr(Terms, 'factors')
        if (any(factors[tcl,] >1)) stop("cluster() cannot be in an interaction")
        if (attr(Terms, "response") ==0)
            stop("formula must have a Surv response")
        # reformulate with the response option puts ` ` around Surv, which messes
        #  up evaluation, hence the fancy dance to replace a piece rather
        #  than recreate
        temp <- attr(Terms, "term.labels")
        oo <- attr(Terms, 'specials')$offset
        if (!is.null(oo)) {
            # add the offset to the set of labels
            ooterm <- rownames(factors)[oo]
            if (oo < tcl) temp <- c(ooterm, temp)
            else temp <- c(temp, ooterm)
        }
        if (is.null(Call$cluster))
            Call$cluster <- attr(Terms, "variables")[[1+tcl]][[2]]
        else warning("cluster appears both in a formula and as an argument, formula term ignored")
        if (is.list(formula)) 
             formula[[1]][[3]] <- reformulate(temp[1-tcl])[[2]]
        else formula[[3]]      <- reformulate(temp[1-tcl])[[2]]

        Call$formula <- formula
        
    }
    
    # create a call to model.frame() that contains the formula (required)
    #  and any other of the relevant optional arguments
    #  but don't evaluate it just yet
    indx <- match(c("formula", "data", "weights", "subset", "na.action",
                    "cluster", "id", "istate"),
                  names(Call), nomatch=0) 
    if (indx[1] ==0) stop("A formula argument is required")
    tform <- Call[c(1,indx)]  # only keep the arguments we wanted
    tform[[1L]] <- quote(stats::model.frame)  # change the function called

    # if the formula is a list, do the first level of processing on it.
    if (is.list(formula)) {
        multiform <- TRUE
        dformula <- formula[[1]]   # the default formula for transitions   
        if (missing(statedata)) covlist <- parsecovar1(formula[-1])
        else {
            if (!inherits(statedata, "data.frame"))
                stop("statedata must be a data frame")
            if (is.null(statedata$state)) 
                stop("statedata data frame must contain a 'state' variable")
            covlist <- parsecovar1(formula[-1], names(statedata))
        }

        # create the master formula, used for model.frame
        # the term.labels + reformulate + environment trio is used in [.terms;
        #  if it's good enough for base R it's good enough for me
        tlab <- unlist(lapply(covlist$rhs, function(x) 
            attr(terms.formula(x$formula), "term.labels")))
        tlab <- c(attr(terms.formula(dformula), "term.labels"), tlab)
        newform <- reformulate(tlab, dformula[[2]])
        environment(newform) <- environment(dformula)
        formula <- newform
        tform$na.action <- na.pass  # defer any missing value work to later
    }
    else {
        multiform <- FALSE   # formula is not a list of expressions
        covlist <- NULL
        dformula <- formula
    }

    # add specials to the formula
    special <- c("strata", "tt", "frailty", "ridge", "pspline")
    tform$formula <- if(missing(data)) terms(formula, special) else
                                      terms(formula, special, data=data)

    # Make "tt" visible for coxph formulas, without making it visible elsewhere
    if (!is.null(attr(tform$formula, "specials")$tt)) {
        coxenv <- new.env(parent= environment(formula))
        assign("tt", function(x) x, envir=coxenv)
        environment(tform$formula) <- coxenv
    }

    # okay, now evaluate the formula
    mf <- eval(tform, parent.frame())
    Terms <- terms(mf)

    # Grab the response variable, and deal with Surv2 objects
    n <- nrow(mf)
    Y <- model.response(mf)
    isSurv2 <- inherits(Y, "Surv2")
    if (isSurv2) {
        # this is Surv2 style data
        # if there were any obs removed due to missing, remake the model frame
        if (length(attr(mf, "na.action"))) {
            tform$na.action <- na.pass
            mf <- eval.parent(tform)
        }
        if (!is.null(attr(Terms, "specials")$cluster))
            stop("cluster() cannot appear in the model statement")
        new <- surv2data(mf)
        mf <- new$mf
        istate <- new$istate
        id <- new$id
        Y <- new$y
        n <- nrow(mf)
    }       
    else {
        if (!is.Surv(Y)) stop("Response must be a survival object")
        id <- model.extract(mf, "id")
        istate <- model.extract(mf, "istate")
    }
    if (n==0) stop("No (non-missing) observations")

    type <- attr(Y, "type")
    multi <- FALSE
    if (type=="mright" || type == "mcounting") multi <- TRUE
    else if (type!='right' && type!='counting')
        stop(paste("Cox model doesn't support \"", type,
                          "\" survival data", sep=''))
    data.n <- nrow(Y)   #remember this before any time transforms

    if (!multi && multiform)
        stop("formula is a list but the response is not multi-state")
    if (multi && length(attr(Terms, "specials")$frailty) >0)
        stop("multi-state models do not currently support frailty terms")
    if (multi && length(attr(Terms, "specials")$pspline) >0)
        stop("multi-state models do not currently support pspline terms")
    if (multi && length(attr(Terms, "specials")$ridge) >0)
        stop("multi-state models do not currently support ridge penalties")

    if (control$timefix) Y <- aeqSurv(Y)
    if (length(attr(Terms, 'variables')) > 2) { # a ~1 formula has length 2
        ytemp <- terms.inner(formula[1:2])
        xtemp <- terms.inner(formula[-2])
        if (any(!is.na(match(xtemp, ytemp))))
            warning("a variable appears on both the left and right sides of the formula")
    }
        
    # The time transform will expand the data frame mf.  To do this
    #  it needs Y and the strata.  Everything else (cluster, offset, weights)
    #  should be extracted after the transform
    #
    strats <- attr(Terms, "specials")$strata
    hasinteractions <- FALSE
    dropterms <- NULL
    if (length(strats)) {
        stemp <- untangle.specials(Terms, 'strata', 1)
        if (length(stemp$vars)==1) strata.keep <- mf[[stemp$vars]]
        else strata.keep <- strata(mf[,stemp$vars], shortlabel=TRUE)
        istrat <- as.integer(strata.keep)

        for (i in stemp$vars) {  #multiple strata terms are allowed
            # The factors attr has one row for each variable in the frame, one
            #   col for each term in the model.  Pick rows for each strata
            #   var, and find if it participates in any interactions.
            if (any(attr(Terms, 'order')[attr(Terms, "factors")[i,] >0] >1))
                hasinteractions <- TRUE  
        }
        if (!hasinteractions) dropterms <- stemp$terms 
    } else istrat <- NULL

    if (hasinteractions && multi)
        stop("multi-state coxph does not support strata*covariate interactions")


    timetrans <- attr(Terms, "specials")$tt
    if (missing(tt)) tt <- NULL
    if (length(timetrans)) {
        if (multi || isSurv2) stop("the tt() transform is not implemented for multi-state or Surv2 models")
         timetrans <- untangle.specials(Terms, 'tt')
         ntrans <- length(timetrans$terms)

         if (is.null(tt)) {
             tt <- function(x, time, riskset, weights){ #default to O'Brien's logit rank
                 obrien <- function(x) {
                     r <- rank(x)
                     (r-.5)/(.5+length(r)-r)
                 }
                 unlist(tapply(x, riskset, obrien))
             }
         }
         if (is.function(tt)) tt <- list(tt)  #single function becomes a list
             
         if (is.list(tt)) {
             if (any(!sapply(tt, is.function))) 
                 stop("The tt argument must contain function or list of functions")
             if (length(tt) != ntrans) {
                 if (length(tt) ==1) {
                     temp <- vector("list", ntrans)
                     for (i in 1:ntrans) temp[[i]] <- tt[[1]]
                     tt <- temp
                 }
                 else stop("Wrong length for tt argument")
             }
         }
         else stop("The tt argument must contain a function or list of functions")

         if (ncol(Y)==2) {
             if (length(strats)==0) {
                 sorted <- order(-Y[,1], Y[,2])
                 newstrat <- rep.int(0L, nrow(Y))
                 newstrat[1] <- 1L
                 }
             else {
                 sorted <- order(istrat, -Y[,1], Y[,2])
                 #newstrat marks the first obs of each strata
                 newstrat <-  as.integer(c(1, 1*(diff(istrat[sorted])!=0))) 
                 }
             if (storage.mode(Y) != "double") storage.mode(Y) <- "double"
             counts <- .Call(Ccoxcount1, Y[sorted,], 
                             as.integer(newstrat))
             tindex <- sorted[counts$index]
         }
         else {
             if (length(strats)==0) {
                 sort.end  <- order(-Y[,2], Y[,3])
                 sort.start<- order(-Y[,1])
                 newstrat  <- c(1L, rep(0, nrow(Y) -1))
             }
             else {
                 sort.end  <- order(istrat, -Y[,2], Y[,3])
                 sort.start<- order(istrat, -Y[,1])
                 newstrat  <- c(1L, as.integer(diff(istrat[sort.end])!=0))
             }
             if (storage.mode(Y) != "double") storage.mode(Y) <- "double"
             counts <- .Call(Ccoxcount2, Y, 
                             as.integer(sort.start -1L),
                             as.integer(sort.end -1L), 
                             as.integer(newstrat))
             tindex <- counts$index
         }
         Y <- Surv(rep(counts$time, counts$nrisk), counts$status)
         type <- 'right'  # new Y is right censored, even if the old was (start, stop]

         mf <- mf[tindex,]
         istrat <- rep(1:length(counts$nrisk), counts$nrisk)
         weights <- model.weights(mf)
         if (!is.null(weights) && any(!is.finite(weights)))
             stop("weights must be finite")  

         tcall <- attr(Terms, 'variables')[timetrans$terms+2]
         pvars <- attr(Terms, 'predvars')
         pmethod <- sub("makepredictcall.", "", as.vector(methods("makepredictcall")))
         for (i in 1:ntrans) {
             newtt <- (tt[[i]])(mf[[timetrans$var[i]]], Y[,1], istrat, weights)
             mf[[timetrans$var[i]]] <- newtt
             nclass <- class(newtt)
             if (any(nclass %in% pmethod)) { # It has a makepredictcall method
                 dummy <- as.call(list(as.name(class(newtt)[1]), tcall[[i]][[2]]))
                 ptemp <- makepredictcall(newtt, dummy)
                 pvars[[timetrans$terms[i]+2]] <- ptemp
             }
         }
         attr(Terms, "predvars") <- pvars
        }
   
    xlevels <- .getXlevels(Terms, mf)

    # grab the cluster, if present.  Using cluster() in a formula is no
    #  longer encouraged
    cluster <- model.extract(mf, "cluster")
    weights <- model.weights(mf)
    # The user can call with cluster, id, robust, or any combination
    # Default for robust: if cluster or any id with > 1 event or 
    #  any weights that are not 0 or 1, then TRUE
    # If only id, treat it as the cluster too
    has.cluster <- !(missing(cluster) || length(cluster)==0) 
    has.id <-      !(missing(id) || length(id)==0)
    has.rwt<-      (!is.null(weights) && any(weights != floor(weights)))
    #has.rwt<- FALSE  # we are rethinking this
    has.robust <-  (!missing(robust) && !is.null(robust))  # arg present
    if (has.id) id <- as.factor(id)

    if (missing(robust) || is.null(robust)) {
        if (has.cluster || has.rwt ||
                 (has.id && (multi || anyDuplicated(id[Y[,ncol(Y)]==1]))))
            robust <- TRUE else robust <- FALSE
    }
    if (!is.logical(robust)) stop("robust must be TRUE/FALSE")

    if (has.cluster) {
        if (!robust) {
            warning("cluster specified with robust=FALSE, cluster ignored")
            ncluster <- 0
            clname <- NULL
        }
        else {
            if (is.factor(cluster)) {
                clname <- levels(cluster)
                cluster <- as.integer(cluster)
            } else {
                clname  <- sort(unique(cluster))
                cluster <- match(cluster, clname)
            }
            ncluster <- length(clname)
        }
    } else {
        if (robust && has.id) {
            # treat the id as both identifier and clustering
            clname <- levels(id)
            cluster <- as.integer(id)
            ncluster <- length(clname)
        }
        else {
            ncluster <- 0  # has neither
        }
    }

    # if the user said "robust", (time1,time2) data, and no cluster or
    #  id, complain about it
    if (robust && is.null(cluster)) {
        if (ncol(Y) ==2 || !has.robust) cluster <- seq.int(1, nrow(mf))
        else stop("one of cluster or id is needed") 
    }
    
    contrast.arg <- NULL  #due to shared code with model.matrix.coxph
    attr(Terms, "intercept") <- 1  # always have a baseline hazard

    if (multi) {
        # check for consistency of the states, and create a transition
        #  matrix
        if (length(id)==0) 
            stop("an id statement is required for multi-state models")

        mcheck <- survcheck2(Y, id, istate)
        # error messages here
        if (mcheck$flag["overlap"] > 0)
            stop("data set has overlapping intervals for one or more subjects")

        transitions <- mcheck$transitions
        istate <- mcheck$istate
        states <- mcheck$states

        #  build tmap, which has one row per term, one column per transition
        if (missing(statedata))
            covlist2 <- parsecovar2(covlist, NULL, dformula= dformula,
                                Terms, transitions, states)
        else covlist2 <- parsecovar2(covlist, statedata, dformula= dformula,
                                Terms, transitions, states)
        tmap <- covlist2$tmap
        if (!is.null(covlist)) {
            # first vector will be true if there is at least 1 transition for which all
            #  covariates are present, second if there is at least 1 for which some are not
            good.tran <- bad.tran <- rep(FALSE, nrow(Y))  
            # We don't need to check interaction terms
            termname <- rownames(attr(Terms, 'factors'))
            trow <- (!is.na(match(rownames(tmap), termname)))

            # create a missing indicator for each term
            termiss <- matrix(0L, nrow(mf), ncol(mf))
            for (i in 1:ncol(mf)) {
                xx <- is.na(mf[[i]])
                if (is.matrix(xx)) termiss[,i] <- apply(xx, 1, any)
                else termiss[,i] <- xx
            }

            for (i in levels(istate)) {
                rindex <- which(istate ==i)
                j <- which(covlist2$mapid[,1] == match(i, states))  #possible transitions
                for (jcol in j) {
                    k <- which(trow & tmap[,jcol] > 0)  # the terms involved in that 
                    bad.tran[rindex] <- (bad.tran[rindex] | 
                                         apply(termiss[rindex, k, drop=FALSE], 1, any))
                    good.tran[rindex] <- (good.tran[rindex] |
                                          apply(!termiss[rindex, k, drop=FALSE], 1, all))
                }
            }
            n.partially.used <- sum(good.tran & bad.tran & !is.na(Y))   
            omit <- (!good.tran & bad.tran) | is.na(Y)
            if (all(omit)) stop("all observations deleted due to missing values")
            temp <- setNames(seq(omit)[omit], attr(mf, "row.names")[omit])
            attr(temp, "class") <- "omit"
            mf <- mf[!omit,, drop=FALSE]
            attr(mf, "na.action") <- temp
            Y <- Y[!omit]
            id <- id[!omit]
            if (length(istate)) istate <- istate[!omit]  # istate can be NULL
        }
    }


    if (length(dropterms)) {
        Terms2 <- Terms[ -dropterms]
        X <- model.matrix(Terms2, mf, constrasts.arg=contrast.arg)
        # we want to number the terms wrt the original model matrix
        temp <- attr(X, "assign")
        shift <- sort(dropterms)
        for (i in seq(along.with=shift))
            temp <- temp + 1*(shift[i] <= temp)
        attr(X, "assign") <- temp 
    }
    else X <- model.matrix(Terms, mf, contrasts.arg=contrast.arg)

    # drop the intercept after the fact, and also drop strata if necessary
    Xatt <- attributes(X) 
    if (hasinteractions) adrop <- c(0, untangle.specials(Terms, "strata")$terms)
    else adrop <- 0
    xdrop <- Xatt$assign %in% adrop  #columns to drop (always the intercept)
    X <- X[, !xdrop, drop=FALSE]
    attr(X, "assign") <- Xatt$assign[!xdrop]
    attr(X, "contrasts") <- Xatt$contrasts
    offset <- model.offset(mf)
    if (is.null(offset) | all(offset==0)) offset <- rep(0., nrow(mf))
    else if (any(!is.finite(offset) | !is.finite(exp(offset)))) 
        stop("offsets must lead to a finite risk score")
        
    weights <- model.weights(mf)
    if (!is.null(weights) && any(!is.finite(weights)))
        stop("weights must be finite")   

    assign <- attrassign(X, Terms)
    contr.save <- attr(X, "contrasts")
    if (sum(Y[, ncol(Y)]) == 0) {
        # No events in the data!
        ncoef <- ncol(X)
        ctemp <- rep(NA, ncoef)
        names(ctemp) <- colnames(X)
        concordance= c(concordant=0, discordant=0, tied.x=0, tied.y=0, tied.xy=0,
                       concordance=NA, std=NA, timefix=FALSE)
        rval <- list(coefficients= ctemp,
                     var = matrix(0.0, ncoef, ncoef),
                     loglik=c(0,0),
                     score =0,
                     iter =0,
                     linear.predictors = offset,
                     residuals = rep(0.0, data.n),
                     means = colMeans(X), method=method,
                     n = data.n, nevent=0, terms=Terms, assign=assign,
                     concordance=concordance,  wald.test=0.0,
                     y = Y, call=Call)
        class(rval) <- "coxph"
        return(rval)
    }
    if (multi) {
        if (length(strats) >0) {
            stratum_map <- tmap[c(1L, strats),] # strats includes Y, + tmap has an extra row
            stratum_map[-1,] <- ifelse(stratum_map[-1,] >0, 1L, 0L)
            if (nrow(stratum_map) > 2) {
                temp <- stratum_map[-1,]
                if (!all(apply(temp, 2, function(x) all(x==0) || all(x==1)))) {
                    # the hard case: some transitions use one strata variable, some
                    #  transitions use another.  We need to keep them separate
                    strata.keep <- mf[,strats]  # this will be a data frame
                    istrat <- sapply(strata.keep, as.numeric)
                }
            }
        }
        else stratum_map <- tmap[1,,drop=FALSE]
        cmap <- parsecovar3(tmap, colnames(X), attr(X, "assign"), covlist2$phbaseline)
        xstack <- stacker(cmap, stratum_map, as.integer(istate), X, Y, strata=istrat,
                          states=states)

        rkeep <- unique(xstack$rindex)
        transitions <- survcheck2(Y[rkeep,], id[rkeep], istate[rkeep])$transitions

        X <- xstack$X
        Y <- xstack$Y
        istrat <- xstack$strata
        if (length(offset)) offset <- offset[xstack$rindex]
        if (length(weights)) weights <- weights[xstack$rindex]
        if (length(cluster)) cluster <- cluster[xstack$rindex]
        t2 <- tmap[-c(1, strats),,drop=FALSE]   # remove the intercept row and strata rows
        r2 <- row(t2)[!duplicated(as.vector(t2)) & t2 !=0]
        c2 <- col(t2)[!duplicated(as.vector(t2)) & t2 !=0]
        a2 <- lapply(seq(along.with=r2), function(i) {cmap[assign[[r2[i]]], c2[i]]})
        # which elements are unique?  
        tab <- table(r2)
        count <- tab[r2]
        names(a2) <- ifelse(count==1, row.names(t2)[r2],
                            paste(row.names(t2)[r2], colnames(cmap)[c2], sep="_"))
        assign <- a2
    }
 
    # infinite covariates are not screened out by the na.omit routines
    #  But this needs to be done after the multi-X part
    if (!all(is.finite(X)))
        stop("data contains an infinite predictor")

   
    # init is checked after the final X matrix has been made
    if (missing(init)) init <- NULL
    else {
        if (length(init) != ncol(X)) stop("wrong length for init argument")
        temp <- X %*% init - sum(colMeans(X) * init) + offset
        # it's okay to have a few underflows, but if all of them are too
        #   small we get all zeros
        if (any(exp(temp) > .Machine$double.xmax) || all(exp(temp)==0))
        stop("initial values lead to overflow or underflow of the exp function")
    }
    
    pterms <- sapply(mf, inherits, 'coxph.penalty')
    if (any(pterms)) {
        pattr <- lapply(mf[pterms], attributes)
        pname <- names(pterms)[pterms]
        # 
        # Check the order of any penalty terms
        ord <- attr(Terms, "order")[match(pname, attr(Terms, 'term.labels'))]
        if (any(ord>1)) stop ('Penalty terms cannot be in an interaction')
        pcols <- assign[match(pname, names(assign))] 
        
        fit <- coxpenal.fit(X, Y, istrat, offset, init=init,
                            control,
                            weights=weights, method=method,
                            row.names(mf), pcols, pattr, assign, 
                            nocenter= nocenter)
    }
    else {
        rname <- row.names(mf)
        if (multi) rname <- rname[xstack$rindex]
        if( method=="breslow" || method =="efron") {
            if (grepl('right', type))  
                fit <- coxph.fit(X, Y, istrat, offset, init, control, 
                                 weights=weights, method=method, 
                                 rname, nocenter=nocenter)
            else  fit <- agreg.fit(X, Y, istrat, offset, init, control, 
                                   weights=weights, method=method, 
                                   rname, nocenter=nocenter)
        }
        else if (method=='exact') {
            if (type== "right")  
                fit <- coxexact.fit(X, Y, istrat, offset, init, control, 
                                    weights=weights, method=method, 
                                    rname, nocenter=nocenter)
            else fit <- agexact.fit(X, Y, istrat, offset, init, control, 
                                    weights=weights, method=method, 
                                    rname, nocenter=nocenter)
        }
        else stop(paste ("Unknown method", method))
    }
    if (is.character(fit)) {
        fit <- list(fail=fit)
        class(fit) <- 'coxph'
    }
    else {
        if (!is.null(fit$coefficients) && any(is.na(fit$coefficients))) {
           vars <- (1:length(fit$coefficients))[is.na(fit$coefficients)]
           msg <-paste("X matrix deemed to be singular; variable",
                           paste(vars, collapse=" "))
           if (!singular.ok) stop(msg)
           # else warning(msg)  # stop being chatty
        }
        fit$n <- data.n
        fit$nevent <- sum(Y[,ncol(Y)])
        fit$terms <- Terms
        fit$assign <- assign
        class(fit) <- fit$class
        fit$class <- NULL

        # don't compute a robust variance if there are no coefficients
        if (robust && !is.null(fit$coefficients) && !all(is.na(fit$coefficients))) {
            fit$naive.var <- fit$var
            # a little sneaky here: by calling resid before adding the
            #   na.action method, I avoid having missings re-inserted
            # I also make sure that it doesn't have to reconstruct X and Y
            fit2 <- c(fit, list(x=X, y=Y, weights=weights))
            if (length(istrat)) fit2$strata <- istrat
            if (length(cluster)) {
                temp <- residuals.coxph(fit2, type='dfbeta', collapse=cluster,
                                          weighted=TRUE)
                # get score for null model
                if (is.null(init))
                        fit2$linear.predictors <- 0*fit$linear.predictors
                else fit2$linear.predictors <- c(X %*% init)
                temp0 <- residuals.coxph(fit2, type='score', collapse=cluster,
                                         weighted=TRUE)
            }
            else {
                temp <- residuals.coxph(fit2, type='dfbeta', weighted=TRUE)
                fit2$linear.predictors <- 0*fit$linear.predictors
                temp0 <- residuals.coxph(fit2, type='score', weighted=TRUE)
            }
            fit$var <- t(temp) %*% temp
            u <- apply(as.matrix(temp0), 2, sum)
            fit$rscore <- coxph.wtest(t(temp0)%*%temp0, u, control$toler.chol)$test
        }

        #Wald test
        if (length(fit$coefficients) && is.null(fit$wald.test)) {  
            #not for intercept only models, or if test is already done
            nabeta <- !is.na(fit$coefficients)
            # The init vector might be longer than the betas, for a sparse term
            if (is.null(init)) temp <- fit$coefficients[nabeta]
            else temp <- (fit$coefficients - 
                          init[1:length(fit$coefficients)])[nabeta]
            fit$wald.test <-  coxph.wtest(fit$var[nabeta,nabeta], temp,
                                          control$toler.chol)$test
        }

        # Concordance.  Done here so that we can use cluster if it is present
        # The returned value is a subset of the full result, partly because it
        #  is all we need, but more for backward compatability with survConcordance.fit
        if (length(cluster))
            temp <- concordancefit(Y, fit$linear.predictors, istrat, weights,
                                              cluster=cluster, reverse=TRUE,
                                    timefix= FALSE)
        else temp <- concordancefit(Y, fit$linear.predictors, istrat, weights,
                                      reverse=TRUE, timefix= FALSE)
        if (is.matrix(temp$count))
             fit$concordance <- c(colSums(temp$count), concordance=temp$concordance,
                                  std=sqrt(temp$var))
        else fit$concordance <- c(temp$count, concordance=temp$concordance, 
                                  std=sqrt(temp$var))
     
        na.action <- attr(mf, "na.action")
        if (length(na.action)) fit$na.action <- na.action
        if (model) {
            if (length(timetrans)) {
                stop("'model=TRUE' not supported for models with tt terms")
            }
            fit$model <- mf
        }
        if (x)  {
            fit$x <- X
            if (length(timetrans)) fit$strata <- istrat
            else if (length(strats)) fit$strata <- strata.keep
        }
        if (y)  fit$y <- Y
        fit$timefix <- control$timefix  # remember this option
    }
    if (!is.null(weights) && any(weights!=1)) fit$weights <- weights
    if (multi) {
        fit$transitions <- transitions
        fit$states <- states
        fit$cmap <- cmap
        fit$stratum_map <- stratum_map   # why not 'stratamap'?  Confusion with fit$strata
        fit$resid <- rowsum(fit$resid, xstack$rindex)
        # add a suffix to each coefficent name.  Those that map to multiple transitions
        #  get the first transition they map to
        single <- apply(cmap, 1, function(x) all(x %in% c(0, max(x)))) #only 1 coef
        cindx <- col(cmap)[match(1:length(fit$coefficients), cmap)]
        rindx <- row(cmap)[match(1:length(fit$coefficients), cmap)]
        suffix <- ifelse(single[rindx], "", paste0("_", colnames(cmap)[cindx]))
        names(fit$coefficients) <- paste0(names(fit$coefficients), suffix)
        if (x) fit$strata <- istrat  # save the expanded strata
        class(fit) <- c("coxphms", class(fit))
    }
    names(fit$means) <- names(fit$coefficients)
     
    fit$formula <- formula(Terms)
    if (length(xlevels) >0) fit$xlevels <- xlevels
    fit$contrasts <- contr.save
    if (any(offset !=0)) fit$offset <- offset

    fit$call <- Call
    fit
    }

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survival documentation built on April 26, 2021, 9:06 a.m.