R/mincontrast.R

In spatstat/spatstat.core: Core Functionality of the 'spatstat' Family

c#'
#'  mincontrast.R
#'
#'  Functions for estimation by minimum contrast
#'
#'  $Revision: 1.122 $ $Date: 2022/03/22 00:52:06 $
#' 


##################  base ################################

safePositiveValue <- function(x, default=.Machine$double.eps) {
  ## ensure x is finite, positive, and acceptable to C routines
  ifelse(is.finite(x),
         pmin(.Machine$double.xmax,
              pmax(.Machine$double.eps,
                   x)),
         default)
}

safeFiniteValue <- function(x, default=0) {
  ## ensure x is finite and acceptable to C routines
  biggest <- .Machine$double.xmax
  ifelse(is.finite(x),
         pmin(biggest,
              pmax(-biggest,
                   x)),
         default)
}

bigvaluerule <- function(objfun, objargs, startpar, ...) {
  ## Determine suitable large number to replace Inf values of objective
  ## Evaluate objective at starting parameter vector
  startval <- do.call(objfun,  list(par=startpar, objargs=objargs, ...))
  ## check 
  with(.Machine, {
    hugeval <- sqrt(double.xmax) * double.eps
    if(abs(startval) > hugeval) {
      warning(paste("Internal error: objective function returns huge value",
                    paren(startval),
                    "which may cause numerical problems"),
              call.=FALSE)
      return(sqrt(double.xmax))
    }
    bigvalue <- min(hugeval, max(sqrt(hugeval), 1024 * abs(startval)))
    return(bigvalue)
  })
}

mincontrast <- local({

  ## objective function (in a format that is re-usable by other code)
  contrast.objective <- function(par, objargs, ...) {
    with(objargs, {
      theo <- theoretical(par=par, rvals, ...)
      if(!is.vector(theo) || !is.numeric(theo))
        stop("theoretical function did not return a numeric vector")
      if(length(theo) != nrvals)
        stop("theoretical function did not return the correct number of values")
      

      ## integrand of discrepancy 
      discrep <- (abs(theo^qq - obsq))^pp
      ## protect C code from weird values
      bigvalue <- BIGVALUE + sqrt(sum(par^2))
      discrep <- safePositiveValue(discrep, default=bigvalue)
      ## rescaled integral of discrepancy
      value <- mean(discrep)
      

      return(value)
    })
  }


  mincontrast <- function(observed, theoretical, startpar,
                          ...,
                          ctrl=list(q = 1/4, p = 2, rmin=NULL, rmax=NULL),
                          fvlab=list(label=NULL, desc="minimum contrast fit"),
                          explain=list(dataname=NULL,
                                       modelname=NULL, fname=NULL),
                          action.bad.values=c("warn", "stop", "silent"),
                          control=list(), stabilize=TRUE, 
                          pspace=NULL) {
    verifyclass(observed, "fv")
    action.bad.values <- match.arg(action.bad.values)

    
    stopifnot(is.function(theoretical))
    if(!any("par" %in% names(formals(theoretical))))
      stop(paste("Theoretical function does not include an argument called",
                 sQuote("par")))

    ## enforce defaults
    ctrl <- resolve.defaults(ctrl, list(q = 1/4, p = 2, rmin=NULL, rmax=NULL))
    fvlab <- resolve.defaults(fvlab,
                              list(label=NULL, desc="minimum contrast fit"))
    explain <- resolve.defaults(explain,
                                list(dataname=NULL, modelname=NULL, fname=NULL))
  
    ## extract vector of r values
    argu <- fvnames(observed, ".x")
    rvals <- observed[[argu]]
    
    ## determine range of r values
    rmin <- ctrl$rmin
    rmax <- ctrl$rmax
    if(!is.null(rmin) && !is.null(rmax)) 
      stopifnot(rmin < rmax && rmin >= 0)
    else {
      alim <- attr(observed, "alim") %orifnull% range(rvals)
      if(is.null(rmax)) rmax <- alim[2]
      if(is.null(rmin)) {
        rmin <- alim[1]
        if(rmin == 0 && identical(explain$fname,"g"))
          rmin <- rmax/1e3 # avoid artefacts at zero in pcf
      }
    }
    ## extract vector of observed values of statistic
    valu <- fvnames(observed, ".y")
    obs <- observed[[valu]]
    ## restrict to [rmin, rmax]
    if(max(rvals) < rmax)
      stop(paste("rmax=", signif(rmax,4),
                 "exceeds the range of available data",
                 "= [", signif(min(rvals),4), ",", signif(max(rvals),4), "]"),
           call.=FALSE)
    sub <- (rvals >= rmin) & (rvals <= rmax)
    rvals <- rvals[sub]
    obs <- obs[sub]
    ## sanity clause
    if(!all(ok <- is.finite(obs))) {
      doomed <- !any(ok)
      if(!doomed && all(ok[-1])) {
        ## common case: all finite except the value for r=0
        whinge <- paste("The value of the empirical function",
                        sQuote(explain$fname),
                        "for r=", rvals[1],
                        "was", paste0(obs[1], "."))
        if(action.bad.values == "stop")
          stop(whinge, call.=FALSE)
        iMIN <- 2
        iMAX <- length(obs)
        success <- TRUE
      } else {
        ## general case: some non-finite values
        whinge <- paste(if(doomed) "All" else "Some",
                        "values of the empirical function",
                        sQuote(explain$fname),
                        "were infinite, NA or NaN.")
        if(doomed || action.bad.values == "stop")
          stop(whinge, call.=FALSE)
        ## trim each end of domain
        ra <- range(which(ok))
        iMIN <- ra[1]
        iMAX <- ra[2]
        success <- all(ok[iMIN:iMAX])
      }
      if(!success) {
        ## Finite and non-finite values are interspersed;
        ## find the longest run of finite values
        z <- rle(ok)
        k <- which.max(z$lengths * z$values)
        ## Run must be at least half of the data
        if(2 * z$lengths[k] > length(ok)) {
          csl <- cumsum(z$lengths)
          iMAX <- csl[k]
          iMIN <- 1L + if(k == 1) 0 else csl[k-1]
          success <- TRUE
        }
      }
      if(success) {
        ## accept trimmed domain
        rmin <- rvals[iMIN]
        rmax <- rvals[iMAX]
        obs   <- obs[iMIN:iMAX]
        rvals <- rvals[iMIN:iMAX]
        sub[sub] <- ok
        if(action.bad.values == "warn") {
          warning(paste(whinge,
                        "Range of r values was reset to",
                        prange(c(rmin, rmax))),
                  call.=FALSE)
        }
      } else stop(paste(whinge,
                        "Unable to recover.",
                        "Please choose a narrower range [rmin, rmax]"),
                  call.=FALSE)
    }
    

    ## pack data into a list
    objargs <- list(theoretical = theoretical,
                    rvals       = rvals,
                    nrvals      = length(rvals),
                    obsq        = obs^(ctrl$q),   ## for efficiency
                    qq          = ctrl$q,
                    pp          = ctrl$p,
                    rmin        = rmin,
                    rmax        = rmax,
                    BIGVALUE    = 1)
    ## determine a suitable large number to replace Inf values of objective
    objargs$BIGVALUE <- bigvaluerule(contrast.objective,
                                     objargs,
                                     startpar, ...)
    

    ## ................... optimization algorithm control parameters .......................
    if(stabilize) {
      ## Numerical stabilisation 
      ## evaluate objective at starting state
      startval <- contrast.objective(startpar, objargs, ...)
      ## use to determine appropriate global scale
      smallscale <- sqrt(.Machine$double.eps)
      fnscale <- max(abs(startval), smallscale)
      parscale <- pmax(abs(startpar), smallscale)
      scaling <- list(fnscale=fnscale, parscale=parscale)
    } else {
      scaling <- list() 
    }
    control <- resolve.defaults(control, scaling, list(trace=0))

    ## .....................................................................................
    ## >>>>>>>>>>>>>>>>>  .  .  .  .  O  P  T  I  M  I  Z  E  .  .  .  .  <<<<<<<<<<<<<<<<<<
    minimum <- optim(startpar, fn=contrast.objective, objargs=objargs, ..., control=control)
    ## .....................................................................................
    
    ## if convergence failed, issue a warning 
    signalStatus(optimStatus(minimum), errors.only=TRUE)
    ## evaluate the fitted theoretical curve
    fittheo <- theoretical(minimum$par, rvals, ...)
    ## pack it up as an `fv' object
    label <- fvlab$label %orifnull% "%s[fit](r)"
    desc  <- fvlab$desc
    fitfv <- bind.fv(observed[sub, ],
                     data.frame(fit=fittheo),
                     label, desc)
    result <- list(par      = minimum$par,
                   fit      = fitfv,
                   opt      = minimum,
                   ctrl     = list(p=ctrl$p,q=ctrl$q,rmin=rmin,rmax=rmax),
                   info     = explain,
                   startpar = startpar,
                   objfun   = contrast.objective,
                   objargs  = objargs,
                   dotargs  = list(...),
                   pspace   = pspace)
    class(result) <- c("minconfit", class(result))
    return(result)
  }

  mincontrast
})


print.minconfit <- function(x, ...) {
  terselevel <- spatstat.options('terse')
  digits <- getOption('digits')
  ## explanatory
  cat(paste("Minimum contrast fit ",
            "(",
            "object of class ",
            dQuote("minconfit"),
            ")",
            "\n", sep=""))
  mo <- x$info$modelname
  fu <- x$info$fname
  da <- x$info$dataname
  cm <- x$covmodel
  if(!is.null(mo))
    cat("Model:", mo, fill=TRUE)
  if(!is.null(cm)) {
    ## Covariance/kernel model and nuisance parameters 
    cat("\t", cm$type, "model:", cm$model, fill=TRUE)
    margs <- cm$margs
    if(!is.null(margs)) {
      nama <- names(margs)
      tags <- ifelse(nzchar(nama), paste(nama, "="), "")
      tagvalue <- paste(tags, margs)
      splat("\t", cm$type, "parameters:",
            paste(tagvalue, collapse=", "))
    }
  }
  if(!is.null(fu)) {
    if(length(fu) > 1) {
      ## compress names like c("K", "inhom") -> "K[inhom]"
      fsub <- paste(fu[-1], collapse=",")
      fu <- paste0(fu[1], paren(fsub, "["))
    }
    if(!is.null(da)) {
      splat("Fitted by matching theoretical", fu, "function to", da)
    } else {
      splat(" based on", fu)
    }
  } else if(!is.null(da)) {
    splat(" fitted to", da)
  }

  if(waxlyrical('space', terselevel))
      cat("\n")
  ## Values
  splat("Internal parameters fitted by minimum contrast ($par):")
  print(x$par, ...)
  if(waxlyrical('space', terselevel))
      cat("\n")
  
  ## Handling new parameters
  isPCP <- x$isPCP %orifnull% x$internal$model!="lgcp"
  cpar <- x$clustpar
  if (!is.null(cpar)) {
    splat("Fitted",
          if(isPCP) "cluster" else "covariance",
          "parameters:")
    print(cpar, digits=digits)
  } else{
    ## Old modelpar field if necessary
    mp <- x$modelpar
    if(!is.null(mp)) {
      splat("Derived parameters of",
            if(!is.null(mo)) mo else "model",
            "($modelpar):")
      print(mp)
    }
  }
  if(length(mu <- x$mu)) {
    if(isPCP) {
      splat("Mean cluster size: ",
            if(is.numeric(mu)) paste(signif(mu, digits), "points") else
            if(is.im(mu)) "[pixel image]" else "[unknown]")
    } else {
      splat("Fitted mean of log of random intensity: ",
            if(is.numeric(mu)) signif(mu, digits) else
            if(is.im(mu)) "[pixel image]" else "[unknown]")
    }
  }
  if(waxlyrical('space', terselevel))
      cat("\n")
  ## Diagnostics
  printStatus(optimStatus(x$opt))
  ## Starting values
  if(waxlyrical('gory', terselevel)){
      cat("\n")
      splat("Starting values of parameters:")
      print(x$startpar)
      ## Algorithm parameters
      ct <- x$ctrl
      splat("Domain of integration:",
            "[",
            signif(ct$rmin,4),
            ",",
            signif(ct$rmax,4),
            "]")
      splat("Exponents:",
            "p=", paste(signif(ct$p, 3), ",",  sep=""),
            "q=", signif(ct$q,3))
  }
  invisible(NULL)
}
              

plot.minconfit <- function(x, ...) {
  xname <- short.deparse(substitute(x))
  xf <- x$fit
  dont.complain.about(xf)
  do.call(plot.fv,
          resolve.defaults(list(quote(xf)),
                           list(...),
                           list(main=xname)))
}

unitname.minconfit <- function(x) {
  unitname(x$fit)
}

"unitname<-.minconfit" <- function(x, value) {
  unitname(x$fit) <- value
  return(x)
}

as.fv.minconfit <- function(x) x$fit

######  convergence status of 'optim' object

optimConverged <- function(x) { x$convergence == 0 }

optimNsteps <- function(x) { x$counts[["function"]] }

optimStatus <- function(x, call=NULL) {
  cgce <- x$convergence
  neval <- x$counts[["function"]]
  switch(paste(cgce),
         "0" = {
           simpleMessage(
                         paste("Converged successfully after", 
                               neval, "function evaluations"),
                         call)
         },
         "1" = simpleWarning(
           paste("Iteration limit maxit was reached after",
                 neval, "function evaluations"),
           call),
         "10" = simpleWarning("Nelder-Mead simplex was degenerate", call),
         "51"= {
           simpleWarning(
                         paste("Warning message from L-BGFS-B method:",
                               sQuote(x$message)),
                         call)
         },
         "52"={
           simpleError(
                         paste("Error message from L-BGFS-B method:",
                               sQuote(x$message)),
                         call)
         },
         simpleWarning(paste("Unrecognised error code", cgce), call)
         )
}

#' general code for collecting status reports

signalStatus <- function(x, errors.only=FALSE) {
  if(is.null(x)) return(invisible(NULL))
  stopifnot(inherits(x, "condition"))
  if(inherits(x, "error")) stop(x)
  if(inherits(x, "warning")) warning(x) 
  if(inherits(x, "message") && !errors.only) message(x)
  return(invisible(NULL))
}

printStatus <- function(x, errors.only=FALSE) {
  if(is.null(x)) return(invisible(NULL))
  prefix <-
    if(inherits(x, "error")) "error: " else 
    if(inherits(x, "warning")) "warning: " else NULL
  if(!is.null(prefix) || !errors.only)
    cat(paste(prefix, conditionMessage(x), "\n", sep=""))
  return(invisible(NULL))
}

accumulateStatus <- function(x, stats=NULL) {
  values      <- stats$values      %orifnull% list()
  frequencies <- stats$frequencies %orifnull% integer(0)
  if(inherits(x, c("error", "warning", "message"))) {
    same <- unlist(lapply(values, identical, y=x))
    if(any(same)) {
      i <- min(which(same))
      frequencies[i] <- frequencies[i] + 1L
    } else {
      values <- append(values, list(x))
      frequencies <- c(frequencies, 1L)
    }
  }
  stats <- list(values=values, frequencies=frequencies)
  return(stats)
}

printStatusList <- function(stats) {
  with(stats,
       {
         for(i in seq_along(values)) {
           printStatus(values[[i]])
           fi <- frequencies[i]
           splat("\t", paren(paste(fi, ngettext(fi, "time", "times"))))
         }
       }
       )
  invisible(NULL)
}

  
############### applications (specific models) ##################


getdataname <- function(defaultvalue, ..., dataname=NULL) {
  if(!is.null(dataname)) dataname else defaultvalue
}
  
thomas.estK <- function(X, startpar=c(kappa=1,scale=1),
                        lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...) {

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)

  if(inherits(X, "fv")) {
    K <- X
    if(!identical(attr(K, "fname")[1], "K"))
      warning("Argument X does not appear to be a K-function")
  } else if(inherits(X, "ppp")) {
    K <- Kest(X)
    dataname <- paste("Kest(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("Thomas")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$K
  
  result <- mincontrast(K, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)",
                          desc="minimum contrast fit of Thomas process"),
                        explain=list(dataname=dataname,
                          fname=attr(K, "fname"),
                          modelname="Thomas process"), ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "sigma2")
  result$par <- par
  ## infer meaningful model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="Thomas")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  return(result)
}

lgcp.estK <- function(X, startpar=c(var=1,scale=1),
                      covmodel=list(model="exponential"), 
                      lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...) {

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)
  
  if(inherits(X, "fv")) {
    K <- X
    if(!identical(attr(K, "fname")[1], "K"))
      warning("Argument X does not appear to be a K-function")
  } else if(inherits(X, "ppp")) {
    K <- Kest(X)
    dataname <- paste("Kest(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("LGCP")
  startpar <- info$checkpar(startpar, native=TRUE)

  ## digest parameters of Covariance model and test validity
  cmodel <- do.call(info$resolveshape, covmodel)$covmodel
  
  theoret <- info$K

  result <- mincontrast(K, theoret, startpar,
                        ctrl=list(q=q, p=p, rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)",
                          desc="minimum contrast fit of LGCP"),
                        explain=list(dataname=dataname,
                          fname=attr(K, "fname"),
                          modelname="log-Gaussian Cox process"),
                        ...,
                        model=cmodel$model,
                        margs=cmodel$margs)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("sigma2", "alpha")
  result$par <- par
  result$covmodel <- cmodel
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="lgcp")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  result$clustargs <- info$outputshape(cmodel$margs)
  return(result)
}

matclust.estK <- function(X, startpar=c(kappa=1,scale=1),
                          lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...) {

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)

  if(inherits(X, "fv")) {
    K <- X
    if(!identical(attr(K, "fname")[1], "K"))
      warning("Argument X does not appear to be a K-function")
  } else if(inherits(X, "ppp")) {
    K <- Kest(X)
    dataname <- paste("Kest(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("MatClust")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$K
  
  result <- mincontrast(K, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)",
                          desc="minimum contrast fit of Matern Cluster process"),
                        explain=list(dataname=dataname,
                          fname=attr(K, "fname"),
                          modelname="Matern Cluster process"),
                        ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "R")
  result$par <- par
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="MatClust")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  return(result)
}

## versions using pcf (suggested by Jan Wild)

thomas.estpcf <- function(X, startpar=c(kappa=1,scale=1),
                          lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...,
                          pcfargs=list()){

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)

  if(inherits(X, "fv")) {
    g <- X
    if(!identical(attr(g, "fname")[1], "g"))
      warning("Argument X does not appear to be a pair correlation function")
  } else if(inherits(X, "ppp")) {
    g <- do.call(pcf.ppp, append(list(X), pcfargs))
    dataname <- paste("pcf(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("Thomas")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$pcf
  
  ## avoid using g(0) as it may be infinite
  argu <- fvnames(g, ".x")
  rvals <- g[[argu]]
  if(rvals[1] == 0 && (is.null(rmin) || rmin == 0)) {
    rmin <- rvals[2]
  }
  result <- mincontrast(g, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(
                          label="%s[fit](r)",
                          desc="minimum contrast fit of Thomas process"),
                        explain=list(
                          dataname=dataname,
                          fname=attr(g, "fname"),
                          modelname="Thomas process"), ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "sigma2")
  result$par <- par
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="Thomas")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  return(result)
}

matclust.estpcf <- function(X, startpar=c(kappa=1,scale=1),
                            lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...,
                            pcfargs=list()){

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)

  if(inherits(X, "fv")) {
    g <- X
    if(!identical(attr(g, "fname")[1], "g"))
      warning("Argument X does not appear to be a pair correlation function")
  } else if(inherits(X, "ppp")) {
    g <- do.call(pcf.ppp, append(list(X), pcfargs))
    dataname <- paste("pcf(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("MatClust")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$pcf
  
  ## avoid using g(0) as it may be infinite
  argu <- fvnames(g, ".x")
  rvals <- g[[argu]]
  if(rvals[1] == 0 && (is.null(rmin) || rmin == 0)) {
    rmin <- rvals[2]
  }
  result <- mincontrast(g, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)",
                          desc="minimum contrast fit of Matern Cluster process"),
                        explain=list(dataname=dataname,
                          fname=attr(g, "fname"),
                          modelname="Matern Cluster process"),
                        ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "R")
  result$par <- par
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="MatClust")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  return(result)
}

lgcp.estpcf <- function(X, startpar=c(var=1,scale=1),
                      covmodel=list(model="exponential"), 
                        lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...,
                        pcfargs=list()) {
  
  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)
  
  if(inherits(X, "fv")) {
    g <- X
    if(!identical(attr(g, "fname")[1], "g"))
      warning("Argument X does not appear to be a pair correlation function")
  } else if(inherits(X, "ppp")) {
    g <- do.call(pcf.ppp, append(list(X), pcfargs))
    dataname <- paste("pcf(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("LGCP")
  startpar <- info$checkpar(startpar, native=TRUE)

  ## digest parameters of Covariance model and test validity
  cmodel <- do.call(info$resolveshape, covmodel)$covmodel
  
  theoret <- info$pcf
  
  result <- mincontrast(g, theoret, startpar,
                        ctrl=list(q=q, p=p, rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)",
                          desc="minimum contrast fit of LGCP"),
                        explain=list(dataname=dataname,
                          fname=attr(g, "fname"),
                          modelname="log-Gaussian Cox process"),
                        ...,
                        model=cmodel$model,
                        margs=cmodel$margs)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("sigma2", "alpha")
  result$par <- par
  result$covmodel <- cmodel
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="lgcp")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  result$clustargs <- info$outputshape(cmodel$margs)
  return(result)
}


cauchy.estK <- function(X, startpar=c(kappa=1,scale=1),
                        lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...) {

## omega: scale parameter of Cauchy kernel function
## eta: scale parameter of Cauchy pair correlation function
## eta = 2 * omega

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)

  if(inherits(X, "fv")) {
    K <- X
    if(!identical(attr(K, "fname")[1], "K"))
      warning("Argument X does not appear to be a K-function")
  } else if(inherits(X, "ppp")) {
    K <- Kest(X)
    dataname <- paste("Kest(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("Cauchy")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$K

  desc <- "minimum contrast fit of Neyman-Scott process with Cauchy kernel"
  result <- mincontrast(K, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)", desc=desc),
                        explain=list(dataname=dataname,
                          fname=attr(K, "fname"),
                          modelname="Cauchy process"), ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "eta2")
  result$par <- par
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="Cauchy")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  return(result)
}


cauchy.estpcf <- function(X, startpar=c(kappa=1,scale=1),
                          lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, ...,
                          pcfargs=list()) {

## omega: scale parameter of Cauchy kernel function
## eta: scale parameter of Cauchy pair correlation function
## eta = 2 * omega

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)

  if(inherits(X, "fv")) {
    g <- X
    if(!identical(attr(g, "fname")[1], "g"))
      warning("Argument X does not appear to be a pair correlation function")
  } else if(inherits(X, "ppp")) {
    g <- do.call(pcf.ppp, append(list(X), pcfargs))
    dataname <- paste("pcf(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  info <- spatstatClusterModelInfo("Cauchy")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$pcf

  ## avoid using g(0) as it may be infinite
  argu <- fvnames(g, ".x")
  rvals <- g[[argu]]
  if(rvals[1] == 0 && (is.null(rmin) || rmin == 0)) {
    rmin <- rvals[2]
  }
  
  desc <- "minimum contrast fit of Neyman-Scott process with Cauchy kernel"
  result <- mincontrast(g, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)", desc=desc),
                        explain=list(dataname=dataname,
                          fname=attr(g, "fname"),
                          modelname="Cauchy process"), ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "eta2")
  result$par <- par
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="Cauchy")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  return(result)
}

vargamma.estK <- function(X, startpar=c(kappa=1,scale=1), nu = -1/4,
                          lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL,
                          ...) {

## nu.ker: smoothness parameter of Variance Gamma kernel function
## omega: scale parameter of kernel function
## nu.pcf: smoothness parameter of Variance Gamma pair correlation function
## eta: scale parameter of Variance Gamma pair correlation function
## nu.pcf = 2 * nu.ker + 1    and    eta = omega

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)
  
  if(inherits(X, "fv")) {
    K <- X
    if(!identical(attr(K, "fname")[1], "K"))
      warning("Argument X does not appear to be a K-function")
  } else if(inherits(X, "ppp")) {
    K <- Kest(X)
    dataname <- paste("Kest(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
    stop("Unrecognised format for argument X")

  ## Catch old nu.ker/nu.pcf syntax and resolve nu-value.
  if(missing(nu))
    nu <- resolve.vargamma.shape(..., allow.default = TRUE)$nu.ker
  check.1.real(nu)
  stopifnot(nu > -1/2)

  info <- spatstatClusterModelInfo("VarGamma")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$K
  
  ## test validity of parameter nu and digest
  cmodel <- info$resolveshape(nu.ker=nu)$covmodel
  margs <- cmodel$margs

  desc <- "minimum contrast fit of Neyman-Scott process with Variance Gamma kernel"
  result <- mincontrast(K, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)", desc=desc),
                        explain=list(dataname=dataname,
                          fname=attr(K, "fname"),
                          modelname="Variance Gamma process"),
                        margs=margs, ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "eta")
  result$par <- par
  result$covmodel <- cmodel
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="VarGamma")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  result$clustargs <- info$outputshape(cmodel$margs)
  return(result)
}


vargamma.estpcf <- function(X, startpar=c(kappa=1,scale=1), nu=-1/4, 
                            lambda=NULL, q=1/4, p=2, rmin=NULL, rmax=NULL, 
                            ..., pcfargs=list()) {

## nu.ker: smoothness parameter of Variance Gamma kernel function
## omega: scale parameter of kernel function
## nu.pcf: smoothness parameter of Variance Gamma pair correlation function
## eta: scale parameter of Variance Gamma pair correlation function
## nu.pcf = 2 * nu.ker + 1    and    eta = omega

  dataname <-
    getdataname(short.deparse(substitute(X), 20), ...)

  if(inherits(X, "fv")) {
    g <- X
    if(!identical(attr(g, "fname")[1], "g"))
      warning("Argument X does not appear to be a pair correlation function")
  } else if(inherits(X, "ppp")) {
    g <- do.call(pcf.ppp, append(list(X), pcfargs))
    dataname <- paste("pcf(", dataname, ")", sep="")
    if(is.null(lambda))
      lambda <- summary(X)$intensity
  } else 
      stop("Unrecognised format for argument X")
  
  ## Catch old nu.ker/nu.pcf syntax and resolve nu-value.
  if(missing(nu))
    nu <- resolve.vargamma.shape(..., allow.default = TRUE)$nu.ker
  check.1.real(nu)
  stopifnot(nu > -1/2)

  info <- spatstatClusterModelInfo("VarGamma")
  startpar <- info$checkpar(startpar, native=TRUE)
  theoret <- info$pcf

  ## test validity of parameter nu and digest 
  cmodel <- info$resolveshape(nu.ker=nu)$covmodel
  margs <- cmodel$margs
  
  ## avoid using g(0) as it may be infinite
  argu <- fvnames(g, ".x")
  rvals <- g[[argu]]
  if(rvals[1] == 0 && (is.null(rmin) || rmin == 0)) {
    rmin <- rvals[2]
  }
  
  desc <- "minimum contrast fit of Neyman-Scott process with Variance Gamma kernel"
  result <- mincontrast(g, theoret, startpar,
                        ctrl=list(q=q, p=p,rmin=rmin, rmax=rmax),
                        fvlab=list(label="%s[fit](r)", desc=desc),
                        explain=list(dataname=dataname,
                          fname=attr(g, "fname"),
                          modelname="Variance Gamma process"),
                        margs=margs,
                        ...)
  ## imbue with meaning
  par <- result$par
  names(par) <- c("kappa", "eta")
  result$par <- par
  result$covmodel <- cmodel
  ## infer model parameters
  result$modelpar <- info$interpret(par, lambda)
  result$internal <- list(model="VarGamma")
  ## parameters in standard form
  result$clustpar <- info$checkpar(par, native=FALSE)
  result$clustargs <- info$outputshape(cmodel$margs)
  return(result)
}