[Vegan-commits] r1109 - pkg/vegan/man
noreply at r-forge.r-project.org
noreply at r-forge.r-project.org
Fri Jan 8 14:59:43 CET 2010
Author: jarioksa
Date: 2010-01-08 14:59:41 +0100 (Fri, 08 Jan 2010)
New Revision: 1109
Modified:
pkg/vegan/man/permatfull.Rd
Log:
formatting
Modified: pkg/vegan/man/permatfull.Rd
===================================================================
--- pkg/vegan/man/permatfull.Rd 2010-01-07 11:39:29 UTC (rev 1108)
+++ pkg/vegan/man/permatfull.Rd 2010-01-08 13:59:41 UTC (rev 1109)
@@ -16,13 +16,14 @@
presence-absence data) based null models can be generated for
community level simulations. Options for preserving characteristics of
the original matrix (rows/columns sums, matrix fill) and
-restricted permutations (based on strata) are discussed in the Details section.}
+restricted permutations (based on strata) are discussed in the
+Details section.}
\usage{
permatfull(m, fixedmar = "both", shuffle = "both", strata = NULL,
-mtype = "count", times = 99)
+ mtype = "count", times = 99)
permatswap(m, method = "quasiswap", fixedmar="both", shuffle = "both",
-strata = NULL, mtype = "count", times = 99, burnin = 0, thin = 1)
+ strata = NULL, mtype = "count", times = 99, burnin = 0, thin = 1)
\method{print}{permat}(x, digits = 3, ...)
\method{summary}{permat}(object, ...)
\method{print}{summary.permat}(x, digits = 2, ...)
@@ -33,101 +34,194 @@
\method{as.mcmc}{permat}(x)
}
\arguments{
- \item{m}{A community data matrix with plots (samples) as rows and species (taxa) as columns.}
- \item{fixedmar}{character, stating which of the row/column sums should be preserved (\code{"none", "rows", "columns", "both"}).}
- \item{strata}{Numeric vector or factor with length same as \code{nrow(m)} for grouping rows within strata for restricted permutations. Unique values or levels are used.}
- \item{mtype}{Matrix data type, either \code{"count"} for count data, or \code{"prab"} for presence-absence type incidence data.}
- \item{times}{Number of permuted matrices.}
- \item{method}{Character for method used for the swap algorithm (\code{"swap"}, \code{"tswap"}, \code{"quasiswap"}, \code{"backtrack"}) as described for function \code{\link{commsimulator}}. If \code{mtype="count"} the \code{"quasiswap"}, \code{"swap"}, \code{"swsh"} and \code{"abuswap"} methods are available (see details).}
- \item{shuffle}{Character, indicating whether individuals (\code{"ind"}), samples (\code{"samp"}) or both (\code{"both"}) should be shuffled, see details.}
- \item{burnin}{Number of null communities discarded before proper analysis in sequential (\code{"swap", "tswap"}) methods.}
- \item{thin}{Number of discarded permuted matrices between two evaluations in sequential (\code{"swap", "tswap"}) methods.}
- \item{x, object}{Object of class \code{"permat"}}
+ \item{m}{A community data matrix with plots (samples) as rows and
+ species (taxa) as columns.}
+ \item{fixedmar}{character, stating which of the row/column sums should
+ be preserved (\code{"none", "rows", "columns", "both"}).}
+ \item{strata}{Numeric vector or factor with length same as
+ \code{nrow(m)} for grouping rows within strata for restricted
+ permutations. Unique values or levels are used.}
+ \item{mtype}{Matrix data type, either \code{"count"} for count data,
+ or \code{"prab"} for presence-absence type incidence data.}
+ \item{times}{Number of permuted matrices.}
+ \item{method}{Character for method used for the swap algorithm
+ (\code{"swap"}, \code{"tswap"}, \code{"quasiswap"},
+ \code{"backtrack"}) as described for function
+ \code{\link{commsimulator}}. If \code{mtype="count"} the
+ \code{"quasiswap"}, \code{"swap"}, \code{"swsh"} and
+ \code{"abuswap"} methods are available (see details).}
+ \item{shuffle}{Character, indicating whether individuals
+ (\code{"ind"}), samples (\code{"samp"}) or both (\code{"both"})
+ should be shuffled, see details.}
+ \item{burnin}{Number of null communities discarded before proper
+ analysis in sequential (\code{"swap", "tswap"}) methods.}
+ \item{thin}{Number of discarded permuted matrices between two
+ evaluations in sequential (\code{"swap", "tswap"}) methods.}
+ \item{x, object}{Object of class \code{"permat"}}
\item{digits}{Number of digits used for rounding.}
- \item{ylab, xlab, col, lty}{graphical parameters for the \code{plot} method.}
- \item{type}{Character, type of plot to be displayed: \code{"bray"} for Bray-Curtis dissimilarities, \code{"chisq"} for Chi-squared values.}
- \item{lowess, plot, text}{Logical arguments for the \code{plot} method, whether a locally weighted regression curve should be drawn, the plot should be drawn, and statistic values should be printed on the plot.}
+ \item{ylab, xlab, col, lty}{graphical parameters for the \code{plot}
+ method.}
+ \item{type}{Character, type of plot to be displayed: \code{"bray"} for
+ Bray-Curtis dissimilarities, \code{"chisq"} for Chi-squared values.}
+ \item{lowess, plot, text}{Logical arguments for the \code{plot}
+ method, whether a locally weighted regression curve should be drawn,
+ the plot should be drawn, and statistic values should be printed on
+ the plot.}
\item{\dots}{Other arguments passed to methods.}
}
\details{
-The function \code{permatfull} is useful when matrix fill is allowed to vary, and matrix type is \code{count}.
-The \code{fixedmar} argument is used to set constraints for permutation.
-If \code{none} of the margins are fixed, cells are randomised within the matrix.
-If \code{rows} or \code{columns} are fixed, cells within rows or columns are randomised, respectively.
-If \code{both} margins are fixed, the \code{\link{r2dtable}} function is used that is based on
-Patefield's (1981) algorithm. For presence absence data, matrix fill should be necessarily fixed, and \code{permatfull}
-is a wrapper for the function \code{\link{commsimulator}}. The \code{r00, r0, c0, quasiswap}
-algorithms of \code{\link{commsimulator}} are used for \code{"none", "rows", "columns", "both"} values
-of the \code{fixedmar} argument, respectively
+ The function \code{permatfull} is useful when matrix fill is
+ allowed to vary, and matrix type is \code{count}. The \code{fixedmar}
+ argument is used to set constraints for permutation. If \code{none}
+ of the margins are fixed, cells are randomised within the matrix. If
+ \code{rows} or \code{columns} are fixed, cells within rows or columns
+ are randomised, respectively. If \code{both} margins are fixed, the
+ \code{\link{r2dtable}} function is used that is based on Patefield's
+ (1981) algorithm. For presence absence data, matrix fill should be
+ necessarily fixed, and \code{permatfull} is a wrapper for the function
+ \code{\link{commsimulator}}. The \code{r00, r0, c0, quasiswap}
+ algorithms of \code{\link{commsimulator}} are used for \code{"none",
+ "rows", "columns", "both"} values of the \code{fixedmar} argument,
+ respectively
-The \code{shuffle} argument only have effect if the \code{mtype = "count"} and \code{permatfull} function is used with \code{"none", "rows", "columns"} values of \code{fixedmar}. All other cases for count data are individual based randomisations. The \code{"samp"} and \code{"both"} options result fixed matrix fill. The \code{"both"} option means that individuals are shuffled among non zero cells ensuring that there are no cell with zeros as a result, than cell (zero and new valued cells) are shuffled.
+ The \code{shuffle} argument only have effect if the \code{mtype =
+ "count"} and \code{permatfull} function is used with \code{"none",
+ "rows", "columns"} values of \code{fixedmar}. All other cases for
+ count data are individual based randomisations. The \code{"samp"} and
+ \code{"both"} options result fixed matrix fill. The \code{"both"}
+ option means that individuals are shuffled among non zero cells
+ ensuring that there are no cell with zeros as a result, then cell
+ (zero and new valued cells) are shuffled.
-The function \code{permatswap} is useful when with matrix fill (i.e. the proportion of empty cells) and row/columns sums should be kept constant. \code{permatswap} uses different kinds of swap algorithms, and row and columns sums are fixed in all cases.
-For presence-absence data, the \code{swap} and \code{tswap} methods of \code{\link{commsimulator}} can be used.
-For count data, a special swap algorithm ('swapcount') is implemented that results in permuted matrices with
-fixed marginals and matrix fill at the same time.
+ The function \code{permatswap} is useful when with matrix fill
+ (i.e. the proportion of empty cells) and row/columns sums should be
+ kept constant. \code{permatswap} uses different kinds of swap
+ algorithms, and row and columns sums are fixed in all cases. For
+ presence-absence data, the \code{swap} and \code{tswap} methods of
+ \code{\link{commsimulator}} can be used. For count data, a special
+ swap algorithm ('swapcount') is implemented that results in permuted
+ matrices with fixed marginals and matrix fill at the same time.
-The 'quasiswapcount' algorithm (\code{method="quasiswap"} and \code{mtype="count"}) uses the same trick as Carsten Dormann's \code{\link[bipartite]{swap.web}} function in the package 'bipartite'. First, a random matrix is generated by the \code{\link{r2dtable}} function retaining row and column sums. Than the original matrix fill is reconstructed by sequential steps to increase or decrease matrix fill in the random matrix. These steps are based on swapping 2x2 submatrices (see 'swapcount' algorithm for details) to maintain row and column totals. This algorithm generates independent matrices in each step, so \code{burnin} and \code{thin} arguments are not considered. This is the default method, because this is not sequential (as 'swapcount' is) so independence of subsequent matrices does not have to be checked.
+ The 'quasiswapcount' algorithm (\code{method="quasiswap"} and
+ \code{mtype="count"}) uses the same trick as Carsten Dormann's
+ \code{\link[bipartite]{swap.web}} function in the package
+ \pkg[bipartite}. First, a random matrix is generated by the
+ \code{\link{r2dtable}} function retaining row and column sums. Then
+ the original matrix fill is reconstructed by sequential steps to
+ increase or decrease matrix fill in the random matrix. These steps are
+ based on swapping 2x2 submatrices (see 'swapcount' algorithm for
+ details) to maintain row and column totals. This algorithm generates
+ independent matrices in each step, so \code{burnin} and \code{thin}
+ arguments are not considered. This is the default method, because this
+ is not sequential (as 'swapcount' is) so independence of subsequent
+ matrices does not have to be checked.
-The 'swapcount' algorithm (\code{method="swap"} and \code{mtype="count"}) tries to find 2x2 submatrices (identified by 2 random row and 2 random column indices), that can be swapped in order to leave column and row totals and fill unchanged. First, the algorithm finds the largest value in the submatrix that can be swapped (\eqn{d}) and whether in diagonal or antidiagonal way. Submatrices that contain values larger than zero in either diagonal or antidiagonal position can be swapped. Swap means that the values in diagonal or antidiagonal positions are decreased by \eqn{d}, while remaining cells are increased by \eqn{d}. A swap is made only if fill doesn't change. This algorithm is sequential, subsequent matrices are not independent, because swaps modify little if the matrix is large. In these cases many burnin steps and thinning is needed to get independent random matrices. Although this algorithm is implemented in C, large burnin and thin values can slow it down considerably. WARNING: according to simulations, this algorithm seems to be biased and non random, thus its use should be avoided!
+ The 'swapcount' algorithm (\code{method="swap"} and
+ \code{mtype="count"}) tries to find 2x2 submatrices (identified by 2
+ random row and 2 random column indices), that can be swapped in order
+ to leave column and row totals and fill unchanged. First, the
+ algorithm finds the largest value in the submatrix that can be swapped
+ (\eqn{d}) and whether in diagonal or antidiagonal way. Submatrices
+ that contain values larger than zero in either diagonal or
+ antidiagonal position can be swapped. Swap means that the values in
+ diagonal or antidiagonal positions are decreased by \eqn{d}, while
+ remaining cells are increased by \eqn{d}. A swap is made only if fill
+ doesn't change. This algorithm is sequential, subsequent matrices are
+ not independent, because swaps modify little if the matrix is
+ large. In these cases many burnin steps and thinning is needed to get
+ independent random matrices. Although this algorithm is implemented in
+ C, large burnin and thin values can slow it down
+ considerably. WARNING: according to simulations, this algorithm seems
+ to be biased and non random, thus its use should be avoided!
-The algorithm \code{"swsh"} in the function \code{permatswap} is a hybrid algorithm. First, it makes binary quasiswaps to keep row and column incidences constant, then non-zero values are modified according to the \code{shuffle} argument (only \code{"samp"} and \code{"both"} are available in this case, because it is applied only on non-zero values).
+ The algorithm \code{"swsh"} in the function \code{permatswap} is a
+ hybrid algorithm. First, it makes binary quasiswaps to keep row and
+ column incidences constant, then non-zero values are modified
+ according to the \code{shuffle} argument (only \code{"samp"} and
+ \code{"both"} are available in this case, because it is applied only
+ on non-zero values).
-The algorithm \code{"abuswap"} produces two kinds of null models (based on \code{fixedmar="columns"} or \code{fixedmar="rows"}) as described in Hardy (2008; randomization scheme 2x and 3x, respectively).
-These preserve column and row occurrences, and column or row sums at the same time.
+ The algorithm \code{"abuswap"} produces two kinds of null models
+ (based on \code{fixedmar="columns"} or \code{fixedmar="rows"}) as
+ described in Hardy (2008; randomization scheme 2x and 3x,
+ respectively). These preserve column and row occurrences, and column
+ or row sums at the same time.
-Constraints on row/column sums, matrix fill, total sum and sums within
-strata can be checked by the \code{summary} method. \code{plot} method is for
-visually testing the randomness of the permuted matrices, especially for the
-sequential swap algorithms. If there are any tendency in the graph, higher \code{burnin} and
-\code{thin} values can help for sequential methods.
-New lines can be added to existing plot with the \code{lines} method.
+ Constraints on row/column sums, matrix fill, total sum and sums within
+ strata can be checked by the \code{summary} method. \code{plot} method
+ is for visually testing the randomness of the permuted matrices,
+ especially for the sequential swap algorithms. If there are any
+ tendency in the graph, higher \code{burnin} and \code{thin} values can
+ help for sequential methods. New lines can be added to existing plot
+ with the \code{lines} method.
-Unrestricted and restricted permutations:
-if \code{strata} is \code{NULL}, functions perform
-unrestricted permutations. Otherwise, it is used
- for restricted permutations. Each strata should contain at least 2 rows
-in order to perform randomization (in case of low row numbers, swap algorithms
-can be rather slow). If the design is not well balanced
-(i.e. same number of observations within each stratum), permuted matrices may be biased
-because same constraints are forced on submatrices of different dimensions. This
-often means, that the number of potential permutations will decrease with their dimensions.
-So the more constraints we put, the less randomness can be expected.
+ Unrestricted and restricted permutations: if \code{strata} is
+ \code{NULL}, functions perform unrestricted permutations. Otherwise,
+ it is used for restricted permutations. Each strata should contain at
+ least 2 rows in order to perform randomization (in case of low row
+ numbers, swap algorithms can be rather slow). If the design is not
+ well balanced (i.e. same number of observations within each stratum),
+ permuted matrices may be biased because same constraints are forced on
+ submatrices of different dimensions. This often means, that the number
+ of potential permutations will decrease with their dimensions. So the
+ more constraints we put, the less randomness can be expected.
-The \code{plot} method is useful for graphically testing for trend and independence of permuted matrices. This is especially important when using sequential algorithms (\code{"swap", "tswap", "abuswap"}).
+ The \code{plot} method is useful for graphically testing for trend and
+ independence of permuted matrices. This is especially important when
+ using sequential algorithms (\code{"swap", "tswap", "abuswap"}).
-The \code{as.ts} method can be used to extract Bray-Curtis dissimilarities or Chi-squared values as time series. This can further used in testing independence (see Examples). The method \code{as.mcmc} is useful for accessing diagnostic tools available in the 'coda' package.
-}
+ The \code{as.ts} method can be used to extract Bray-Curtis
+ dissimilarities or Chi-squared values as time series. This can further
+ used in testing independence (see Examples). The method \code{as.mcmc}
+ is useful for accessing diagnostic tools available in the \pkg{coda}
+ package. }
-\value{
-Functions \code{permatfull} and \code{permatswap} return an object of class \code{"permat"} containing the the function call (\code{call}), the original data matrix used for permutations (\code{orig}) and a list of permuted matrices with length \code{times} (\code{perm}).
+\value{ Functions \code{permatfull} and \code{permatswap} return an
+ object of class \code{"permat"} containing the the function call
+ (\code{call}), the original data matrix used for permutations
+ (\code{orig}) and a list of permuted matrices with length \code{times}
+ (\code{perm}).
-The \code{summary} method returns various statistics as a list (including mean Bray-Curtis dissimilarities calculated pairwise among original and permuted matrices, Chi-square statistics, and check results of the constraints; see Examples). Note that when \code{strata} is used in the original call, summary calculation may take longer.
+ The \code{summary} method returns various statistics as a list
+ (including mean Bray-Curtis dissimilarities calculated pairwise among
+ original and permuted matrices, Chi-square statistics, and check
+ results of the constraints; see Examples). Note that when
+ \code{strata} is used in the original call, summary calculation may
+ take longer.
-The \code{plot} creates a plot as a side effect.
+ The \code{plot} creates a plot as a side effect.
-The \code{as.ts} method returns an object of class 'ts'.
-}
-\references{
-Original references for presence-absence algorithms are given on help
-page of \code{\link{commsimulator}}.
+ The \code{as.ts} method returns an object of class \code{"ts"}. }
-Hardy, O. J. (2008) Testing the spatial phylogenetic structure of local communities: statistical performances of different null models and test statistics on a locally neutral community. Journal of Ecology 96, 914--926.
-Patefield, W. M. (1981) Algorithm AS159. An efficient method of generating r x c tables with given row and column totals.
-Applied Statistics 30, 91--97.
+\references{ Original references for presence-absence algorithms are
+ given on help page of \code{\link{commsimulator}}.
+
+ Hardy, O. J. (2008) Testing the spatial phylogenetic structure of
+ local communities: statistical performances of different null models
+ and test statistics on a locally neutral community. Journal of Ecology
+ 96, 914--926.
+
+ Patefield, W. M. (1981) Algorithm AS159. An efficient method of
+ generating r x c tables with given row and column totals.
+ Applied Statistics 30, 91--97.
}
-\author{\enc{P\'eter S\'olymos}{Peter Solymos}, \email{solymos at ualberta.ca} and Jari Oksanen}
+\author{\enc{P\'eter S\'olymos}{Peter Solymos},
+\email{solymos at ualberta.ca} and Jari Oksanen}
-\seealso{
-For other functions to permute matrices: \code{\link{commsimulator}}, \code{\link{r2dtable}}, \code{\link{sample}}, \code{\link[bipartite]{swap.web}}.
+\seealso{ For other functions to permute matrices:
+\code{\link{commsimulator}}, \code{\link{r2dtable}},
+\code{\link{sample}}, \code{\link[bipartite]{swap.web}}.
-For the use of these permutation algorithms: \code{\link{oecosimu}}, \code{\link{adipart}}, \code{\link{hiersimu}}.
+For the use of these permutation algorithms: \code{\link{oecosimu}},
+\code{\link{adipart}}, \code{\link{hiersimu}}.
-For time-series diagnostics: \code{\link{Box.test}}, \code{\link{lag.plot}}, \code{\link{tsdiag}}, \code{\link{ar}}, \code{\link{arima}}
-}
+For time-series diagnostics: \code{\link{Box.test}},
+\code{\link{lag.plot}}, \code{\link{tsdiag}}, \code{\link{ar}},
+\code{\link{arima}} }
+
\examples{
## A simple artificial community data matrix.
m <- matrix(c(
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