Documented difflong()

Author: baddstats

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: spatstat.utils
-Version: 3.2-0.003
-Date: 2025-12-29
+Version: 3.2-0.004
+Date: 2026-01-04
 Title: Utility Functions for 'spatstat'
 Authors@R: c(person("Adrian", "Baddeley", 
                     role = c("aut", "cre"),

NEWS

@@ -1,9 +1,14 @@
 
-        CHANGES IN spatstat.utils VERSION 3.2-0.003
+        CHANGES IN spatstat.utils VERSION 3.2-0.004
 
 OVERVIEW
 
-    o Internal improvements.
+    o Lagged difference of long vector.
+
+NEW FUNCTIONS
+
+    o difflong
+    Calculates diff() for a long vector.
 
         CHANGES IN spatstat.utils VERSION 3.2-0
 

inst/doc/packagesizes.txt

@@ -31,4 +31,4 @@ date version nhelpfiles nobjects ndatasets Rlines srclines
 "2025-05-15" "3.1-4" 42 193 0 3689 2462
 "2025-07-17" "3.1-5" 42 194 0 3703 2462
 "2025-09-20" "3.2-0" 42 195 0 3716 2462
-"2025-12-29" "3.2-0.003" 42 196 0 3754 2535
+"2026-01-04" "3.2-0.004" 43 196 0 3754 2535

inst/info/packagesizes.txt

@@ -31,4 +31,4 @@ date version nhelpfiles nobjects ndatasets Rlines srclines
 "2025-05-15" "3.1-4" 42 193 0 3689 2462
 "2025-07-17" "3.1-5" 42 194 0 3703 2462
 "2025-09-20" "3.2-0" 42 195 0 3716 2462
-"2025-12-29" "3.2-0.003" 42 196 0 3754 2535
+"2026-01-04" "3.2-0.004" 43 196 0 3754 2535

man/difflong.Rd

@@ -0,0 +1,58 @@
+\name{difflong}
+\alias{difflong}
+\title{
+  Lagged Differences for a Long Vector
+}
+\description{
+  Calculate the lagged difference of a long vector.
+}
+\usage{
+difflong(x, drop = TRUE)
+}
+\arguments{
+  \item{x}{
+    Numeric or integer vector.
+  }
+  \item{drop}{
+    Logical value. See Details.
+  }
+}
+\details{
+  A \sQuote{long vector} is a vector with more than
+  \eqn{2^31 - 1} elements (the largest possible 32-bit integer).
+  Long vectors are supported in \R on 64-bit computer systems.
+  This feature was introduced in \R version 3.0.0.
+  
+  Although long vectors are permitted, not all functions in \R
+  have been extended to handle long vectors.
+
+  The base \R function \code{\link{diff}} currently does not handle
+  a long vector, and may cause the entire \R
+  session to be terminated.
+
+  The function \code{difflong} is a temporary replacement
+  for \code{\link{diff}} in the simplest case:
+  \code{difflong(x)} is a replacement for \code{diff(x)}.
+
+  If \code{drop=TRUE} (the default), 
+  the result of \code{difflong(x)} is equivalent to \code{diff(x)},
+  a vector with length equal to \code{length(x) - 1}.
+  If \code{drop=FALSE} the result of \code{difflong(x, FALSE)} has the
+  same length as \code{x}; the first entry is zero, and the subsequent
+  entries are equivalent to \code{diff(x)}.
+}
+\value{
+  A vector of the same type as \code{x}.
+}
+\author{
+  \adrian.
+}
+\seealso{
+  \code{\link{diff}}
+}
+\examples{
+  x <- sample(1:5)
+  diff(x)
+  difflong(x)
+}
+\keyword{manip}

man/spatstat.utils-internal.Rd

@@ -14,7 +14,6 @@
 \alias{choptext}
 \alias{choptextline}
 \alias{complaining}
-\alias{difflong}
 \alias{distpl}               
 \alias{distppl}
 \alias{distppll}
@@ -127,7 +126,6 @@ check.satisfies(cond, xname, should, context, fatal, warn)
 choptext(\dots, prefix, indent)
 choptextline(st, w, prefix, indent)
 complaining(whinge, fatal, value)
-difflong(x, drop)
 distpl(p, l)               
 distppl(p, l)
 distppll(p, l, mintype, method, listit)

tests/numerical.R

@@ -3,6 +3,13 @@
 
 require(spatstat.utils)
 
+#' difflong() calculates diff() for long vectors
+#' Test agreement on a short vector
+n <- sample((-1000):1000, 1000, replace=TRUE)
+stopifnot(all(diff(n) == difflong(n)))
+x <- as.double(n)
+stopifnot(all(diff(x) == difflong(x)))
+
 #' validity of orderstats, orderwhich
 x <- unique(runif(100))
 if(!all(orderstats(x, 2:5) == sort(x)[2:5]))