[Returnanalytics-commits] r3600 - in pkg/FactorAnalytics: . R man

noreply at r-forge.r-project.org noreply at r-forge.r-project.org
Mon Feb 9 21:05:44 CET 2015


Author: chenyian
Date: 2015-02-09 21:05:44 +0100 (Mon, 09 Feb 2015)
New Revision: 3600

Added:
   pkg/FactorAnalytics/R/fitTsfmUpDn.r
   pkg/FactorAnalytics/man/fitTsfmUpDn.Rd
Modified:
   pkg/FactorAnalytics/NAMESPACE
   pkg/FactorAnalytics/R/fitTsfmLagBeta.r
   pkg/FactorAnalytics/R/fitTsfmMT.r
   pkg/FactorAnalytics/man/fitTsfmLagBeta.Rd
   pkg/FactorAnalytics/man/fitTsfmMT.Rd
Log:
The first version of fitTsfmUpDn.r. It is a wrapper function of fitTsfm.r and returns a list object containing "Up" and "Dn". Both are class of "Tsfm".   

Modified: pkg/FactorAnalytics/NAMESPACE
===================================================================
--- pkg/FactorAnalytics/NAMESPACE	2015-02-08 01:33:35 UTC (rev 3599)
+++ pkg/FactorAnalytics/NAMESPACE	2015-02-09 20:05:44 UTC (rev 3600)
@@ -32,6 +32,7 @@
 export(fitTsfm)
 export(fitTsfmMT)
 export(fitTsfmLagBeta)
+export(fitTsfmUpDn)
 export(fmCov)
 export(fmEsDecomp)
 export(fmSdDecomp)

Modified: pkg/FactorAnalytics/R/fitTsfmLagBeta.r
===================================================================
--- pkg/FactorAnalytics/R/fitTsfmLagBeta.r	2015-02-08 01:33:35 UTC (rev 3599)
+++ pkg/FactorAnalytics/R/fitTsfmLagBeta.r	2015-02-09 20:05:44 UTC (rev 3600)
@@ -58,8 +58,8 @@
 #' @param asset.names vector containing names of assets, whose returns or 
 #' excess returns are the dependent variable.
 #' @param factor.names vector containing names of the macroeconomic factors.
-#' @param mkt.name name of the column for market excess returns (Rm-Rf); this 
-#' is necessary to add market timing factors. Default is NULL.
+#' @param mkt.name name of the column for market excess returns (Rm-Rf). It 
+#' is required for a lagged Betas factor model. 
 #' @param rf.name name of the column of risk free rate variable to calculate 
 #' excess returns for all assets (in \code{asset.names}) and factors (in 
 #' \code{factor.names}). Default is NULL, and no action is taken.
@@ -142,7 +142,7 @@
 #' # load data from the database
 #' data(managers)
 #' 
-#' # example: Market-timing factors with OLS fit
+#' # example: A lagged Beetas model with OLS fit
 #' fit <- fitTsfmLagBeta(asset.names=colnames(managers[,(1:6)]),LagBeta=2,
 #'                       factor.names="SP500.TR",mkt.name="SP500.TR",
 #'                       rf.name="US.3m.TR",data=managers)

Modified: pkg/FactorAnalytics/R/fitTsfmMT.r
===================================================================
--- pkg/FactorAnalytics/R/fitTsfmMT.r	2015-02-08 01:33:35 UTC (rev 3599)
+++ pkg/FactorAnalytics/R/fitTsfmMT.r	2015-02-09 20:05:44 UTC (rev 3600)
@@ -58,8 +58,8 @@
 #' @param asset.names vector containing names of assets, whose returns or 
 #' excess returns are the dependent variable.
 #' @param factor.names vector containing names of the macroeconomic factors.
-#' @param mkt.name name of the column for market excess returns (Rm-Rf); this 
-#' is necessary to add market timing factors. Default is NULL.
+#' @param mkt.name name of the column for market excess returns (Rm-Rf); It 
+#' is required for a market timing model.
 #' @param rf.name name of the column of risk free rate variable to calculate 
 #' excess returns for all assets (in \code{asset.names}) and factors (in 
 #' \code{factor.names}). Default is NULL, and no action is taken.

Added: pkg/FactorAnalytics/R/fitTsfmUpDn.r
===================================================================
--- pkg/FactorAnalytics/R/fitTsfmUpDn.r	                        (rev 0)
+++ pkg/FactorAnalytics/R/fitTsfmUpDn.r	2015-02-09 20:05:44 UTC (rev 3600)
@@ -0,0 +1,205 @@
+#' @title Fit a up and down market factor model using time series regression
+#' 
+#' @description This is a wrapper function to fits a up/down market model for one 
+#' or more asset returns or excess returns using time series regression. 
+#' Users can choose between ordinary least squares-OLS, discounted least 
+#' squares-DLS (or) robust regression. Several variable selection options  
+#' including Stepwise, Subsets, Lars are available as well. An object of class 
+#' \code{"tsfm"} is returned.
+#' 
+#' @details 
+#' Typically, factor models are fit using excess returns. \code{rf.name} gives 
+#' the option to supply a risk free rate variable to subtract from each asset 
+#' return and factor to compute excess returns. 
+#' 
+#' Estimation method "OLS" corresponds to ordinary least squares using 
+#' \code{\link[stats]{lm}}, "DLS" is discounted least squares (weighted least 
+#' squares with exponentially declining weights that sum to unity), and, 
+#' "Robust" is robust regression (using \code{\link[robust]{lmRob}}). 
+#' 
+#' If \code{variable.selection="none"}, uses all the factors and performs no 
+#' variable selection. Whereas, "stepwise" performs traditional stepwise 
+#' LS or Robust regression (using \code{\link[stats]{step}} or 
+#' \code{\link[robust]{step.lmRob}}), that starts from the initial set of 
+#' factors and adds/subtracts factors only if the regression fit, as measured 
+#' by the Bayesian Information Criterion (BIC) or Akaike Information Criterion 
+#' (AIC), improves. And, "subsets" enables subsets selection using 
+#' \code{\link[leaps]{regsubsets}}; chooses the best performing subset of any 
+#' given size or within a range of subset sizes. Different methods such as 
+#' exhaustive search (default), forward or backward stepwise, or sequential 
+#' replacement can be employed.See \code{\link{fitTsfm.control}} for more 
+#' details on the control arguments.
+#'  
+#' \code{variable.selection="lars"} corresponds to least angle regression 
+#' using \code{\link[lars]{lars}} with variants "lasso" (default), "lar", 
+#' "stepwise" or "forward.stagewise". Note: If \code{variable.selection="lars"}, 
+#' \code{fit.method} will be ignored.
+#' 
+#' 
+#' \subsection{Data Processing}{
+#' 
+#' Note about NAs: Before model fitting, incomplete cases are removed for 
+#' every asset (return data combined with respective factors' return data) 
+#' using \code{\link[stats]{na.omit}}. Otherwise, all observations in 
+#' \code{data} are included.
+#' 
+#' Note about \code{asset.names} and \code{factor.names}: Spaces in column 
+#' names of \code{data} will be converted to periods as \code{fitTsfm} works 
+#' with \code{xts} objects internally and colnames won't be left as they are.
+#' }
+#' 
+#' @param asset.names vector containing names of assets, whose returns or 
+#' excess returns are the dependent variable.
+#' @param factor.names vector containing names of the macroeconomic factors.
+#' @param mkt.name name of the column for market excess returns (Rm-Rf). It 
+#' is required for a up/down market model. 
+#' @param rf.name name of the column of risk free rate variable to calculate 
+#' excess returns for all assets (in \code{asset.names}) and factors (in 
+#' \code{factor.names}). Default is NULL, and no action is taken.
+#' @param data vector, matrix, data.frame, xts, timeSeries or zoo object  
+#' containing column(s) named in \code{asset.names}, \code{factor.names} and 
+#' optionally, \code{mkt.name} and \code{rf.name}.
+#' @param fit.method the estimation method, one of "OLS", "DLS" or "Robust". 
+#' See details. Default is "OLS". 
+#' @param variable.selection the variable selection method, one of "none", 
+#' "stepwise","subsets","lars". See details. Default is "none".
+#' \code{mkt.name} is required if any of these options are to be implemented.
+#' @param control list of control parameters. The default is constructed by 
+#' the function \code{\link{fitTsfm.control}}. See the documentation for 
+#' \code{\link{fitTsfm.control}} for details.
+#' @param ... arguments passed to \code{\link{fitTsfm.control}}
+#' 
+#' @return 
+#' 
+#' fitTsfmUpDn returns a list object containing \code{Up} and \code{Dn}. 
+#' Both \code{Up} and \code{Dn} are class of \code{"tsfm"}. 
+#'  
+#' fitTsfm returns an object of class \code{"tsfm"} for which 
+#' \code{print}, \code{plot}, \code{predict} and \code{summary} methods exist. 
+#' 
+#' The generic accessor functions \code{coef}, \code{fitted} and 
+#' \code{residuals} extract various useful features of the fit object. 
+#' Additionally, \code{fmCov} computes the covariance matrix for asset returns 
+#' based on the fitted factor model
+#' 
+#' An object of class \code{"tsfm"} is a list containing the following 
+#' components:
+#' \item{asset.fit}{list of fitted objects for each asset. Each object is of 
+#' class \code{lm} if \code{fit.method="OLS" or "DLS"}, class \code{lmRob} if 
+#' the \code{fit.method="Robust"}, or class \code{lars} if 
+#' \code{variable.selection="lars"}.}
+#' \item{alpha}{length-N vector of estimated alphas.}
+#' \item{beta}{N x K matrix of estimated betas.}
+#' \item{r2}{length-N vector of R-squared values.}
+#' \item{resid.sd}{length-N vector of residual standard deviations.}
+#' \item{fitted}{xts data object of fitted values; iff 
+#' \code{variable.selection="lars"}}
+#' \item{call}{the matched function call.}
+#' \item{data}{xts data object containing the assets and factors.}
+#' \item{asset.names}{asset.names as input.}
+#' \item{factor.names}{factor.names as input.}
+#' \item{fit.method}{fit.method as input.}
+#' \item{variable.selection}{variable.selection as input.}
+#' Where N is the number of assets, K is the number of factors and T is the 
+#' number of time periods.
+#' 
+#' @author Yi-An Chen.
+#' 
+#' @references 
+#' Christopherson, J. A., Carino, D. R., & Ferson, W. E. (2009). Portfolio 
+#' performance measurement and benchmarking. McGraw Hill Professional.
+#' 
+#' Efron, B., Hastie, T., Johnstone, I., & Tibshirani, R. (2004). Least angle 
+#' regression. The Annals of statistics, 32(2), 407-499. 
+#' 
+#' Hastie, T., Tibshirani, R., Friedman, J., Hastie, T., Friedman, J., & 
+#' Tibshirani, R. (2009). The elements of statistical learning (Vol. 2, No. 1). 
+#' New York: Springer.
+#' 
+#' Henriksson, R. D., & Merton, R. C. (1981). On market timing and investment 
+#' performance. II. Statistical procedures for evaluating forecasting skills. 
+#' Journal of business, 513-533.
+#' 
+#' Treynor, J., & Mazuy, K. (1966). Can mutual funds outguess the market. 
+#' Harvard business review, 44(4), 131-136.
+#' 
+#' @seealso The \code{tsfm} methods for generic functions: 
+#' \code{\link{plot.tsfm}}, \code{\link{predict.tsfm}}, 
+#' \code{\link{print.tsfm}} and \code{\link{summary.tsfm}}. 
+#' 
+#' And, the following extractor functions: \code{\link[stats]{coef}}, 
+#' \code{\link[stats]{fitted}}, \code{\link[stats]{residuals}},
+#' \code{\link{fmCov}}, \code{\link{fmSdDecomp}}, \code{\link{fmVaRDecomp}} 
+#' and \code{\link{fmEsDecomp}}.
+#' 
+#' \code{\link{paFm}} for Performance Attribution. 
+#' 
+#' @examples
+#' # load data from the database
+#' data(managers)
+#' 
+#' # example: Up and down market factor model with OLS fit
+#' fitUpDn <- fitTsfmUpDn(asset.names=colnames(managers[,(1:6)]),mkt.name="SP500.TR",
+#'                        data=managers, fit.method="OLS",control=NULL)
+#'  # List object
+#'  fitUpDn
+#'  
+#'  summary(fitUpDn$Up)
+#'  summary(fitUpDn$Dn)
+#'  
+#' @importFrom PerformanceAnalytics checkData
+#' @importFrom robust lmRob step.lmRob
+#' @importFrom leaps regsubsets
+#' @importFrom lars lars cv.lars
+#' 
+#' @export
+
+
+fitTsfmUpDn <- function(asset.names, factor.names=NULL, mkt.name=NULL, rf.name=NULL, 
+                                 data=data, fit.method=c("OLS","DLS","Robust"), 
+                                 variable.selection=c("none","stepwise","subsets","lars"),
+                                 control=fitTsfm.control(...),...) {
+
+  if (is.null(mkt.name)){
+    stop("Missing argument: mkt.name has to be specified for up and down market model.")
+  }  
+  
+ 
+  
+  factor.names <- union(factor.names,mkt.name)
+  
+  # convert data into an xts object and hereafter work with xts objects
+  data.xts <- checkData(data)
+  # convert index to 'Date' format for uniformity 
+  time(data.xts) <- as.Date(time(data.xts))
+  
+  # extract columns to be used in the time series regression
+  dat.xts <- merge(data.xts[,asset.names], data.xts[,factor.names])
+  ### After merging xts objects, the spaces in names get converted to periods
+  
+  # convert all asset and factor returns to excess return form if specified
+  if (!is.null(rf.name)) {
+    dat.xts <- "[<-"(dat.xts,,vapply(dat.xts, function(x) x-data.xts[,rf.name], 
+                                     FUN.VALUE = numeric(nrow(dat.xts))))
+    warning("Up market is defined as the excess Market returns is no less than 0.")
+  } else {
+    warning("Up market is defined as the Market returns is no less than 0.")
+  }
+  
+  mkt <- dat.xts[,mkt.name]
+  # up market
+  dataUp.xts <- dat.xts[mkt >= 0]
+  
+  fitUp <-  fitTsfm(asset.names=asset.names,factor.names=factor.names,mkt.name=mkt.name,rf.name=rf.name,
+                     data=dataUp.xts,fit.method=fit.method,variable.selection=variable.selection,
+                     control=control)
+
+  
+  # down market
+  dataDn.xts <- dat.xts[mkt < 0]
+  fitDn <-  fitTsfm(asset.names=asset.names,factor.names=factor.names,mkt.name=mkt.name,rf.name=rf.name,
+                     data=dataDn.xts,fit.method=fit.method,variable.selection=variable.selection,
+                     control=control)
+  
+return(list(Up = fitUp, Dn = fitDn))
+} 

Modified: pkg/FactorAnalytics/man/fitTsfmLagBeta.Rd
===================================================================
--- pkg/FactorAnalytics/man/fitTsfmLagBeta.Rd	2015-02-08 01:33:35 UTC (rev 3599)
+++ pkg/FactorAnalytics/man/fitTsfmLagBeta.Rd	2015-02-09 20:05:44 UTC (rev 3600)
@@ -15,8 +15,8 @@
 
 \item{factor.names}{vector containing names of the macroeconomic factors.}
 
-\item{mkt.name}{name of the column for market excess returns (Rm-Rf); this
-is necessary to add market timing factors. Default is NULL.}
+\item{mkt.name}{name of the column for market excess returns (Rm-Rf). It
+is required for a lagged Betas factor model.}
 
 \item{rf.name}{name of the column of risk free rate variable to calculate
 excess returns for all assets (in \code{asset.names}) and factors (in
@@ -132,7 +132,7 @@
 # load data from the database
 data(managers)
 
-# example: Market-timing factors with OLS fit
+# example: A lagged Beetas model with OLS fit
 fit <- fitTsfmLagBeta(asset.names=colnames(managers[,(1:6)]),LagBeta=2,
                       factor.names="SP500.TR",mkt.name="SP500.TR",
                       rf.name="US.3m.TR",data=managers)

Modified: pkg/FactorAnalytics/man/fitTsfmMT.Rd
===================================================================
--- pkg/FactorAnalytics/man/fitTsfmMT.Rd	2015-02-08 01:33:35 UTC (rev 3599)
+++ pkg/FactorAnalytics/man/fitTsfmMT.Rd	2015-02-09 20:05:44 UTC (rev 3600)
@@ -15,8 +15,8 @@
 
 \item{factor.names}{vector containing names of the macroeconomic factors.}
 
-\item{mkt.name}{name of the column for market excess returns (Rm-Rf); this
-is necessary to add market timing factors. Default is NULL.}
+\item{mkt.name}{name of the column for market excess returns (Rm-Rf); It
+is required for a market timing model.}
 
 \item{rf.name}{name of the column of risk free rate variable to calculate
 excess returns for all assets (in \code{asset.names}) and factors (in

Added: pkg/FactorAnalytics/man/fitTsfmUpDn.Rd
===================================================================
--- pkg/FactorAnalytics/man/fitTsfmUpDn.Rd	                        (rev 0)
+++ pkg/FactorAnalytics/man/fitTsfmUpDn.Rd	2015-02-09 20:05:44 UTC (rev 3600)
@@ -0,0 +1,170 @@
+% Generated by roxygen2 (4.1.0): do not edit by hand
+% Please edit documentation in R/fitTsfmUpDn.r
+\name{fitTsfmUpDn}
+\alias{fitTsfmUpDn}
+\title{Fit a up and down market factor model using time series regression}
+\usage{
+fitTsfmUpDn(asset.names, factor.names = NULL, mkt.name = NULL,
+  rf.name = NULL, data = data, fit.method = c("OLS", "DLS", "Robust"),
+  variable.selection = c("none", "stepwise", "subsets", "lars"),
+  control = fitTsfm.control(...), ...)
+}
+\arguments{
+\item{asset.names}{vector containing names of assets, whose returns or
+excess returns are the dependent variable.}
+
+\item{factor.names}{vector containing names of the macroeconomic factors.}
+
+\item{mkt.name}{name of the column for market excess returns (Rm-Rf). It
+is required for a up/down market model.}
+
+\item{rf.name}{name of the column of risk free rate variable to calculate
+excess returns for all assets (in \code{asset.names}) and factors (in
+\code{factor.names}). Default is NULL, and no action is taken.}
+
+\item{data}{vector, matrix, data.frame, xts, timeSeries or zoo object
+containing column(s) named in \code{asset.names}, \code{factor.names} and
+optionally, \code{mkt.name} and \code{rf.name}.}
+
+\item{fit.method}{the estimation method, one of "OLS", "DLS" or "Robust".
+See details. Default is "OLS".}
+
+\item{variable.selection}{the variable selection method, one of "none",
+"stepwise","subsets","lars". See details. Default is "none".
+\code{mkt.name} is required if any of these options are to be implemented.}
+
+\item{control}{list of control parameters. The default is constructed by
+the function \code{\link{fitTsfm.control}}. See the documentation for
+\code{\link{fitTsfm.control}} for details.}
+
+\item{...}{arguments passed to \code{\link{fitTsfm.control}}}
+}
+\value{
+fitTsfmUpDn returns a list object containing \code{Up} and \code{Dn}.
+Both \code{Up} and \code{Dn} are class of \code{"tsfm"}.
+
+fitTsfm returns an object of class \code{"tsfm"} for which
+\code{print}, \code{plot}, \code{predict} and \code{summary} methods exist.
+
+The generic accessor functions \code{coef}, \code{fitted} and
+\code{residuals} extract various useful features of the fit object.
+Additionally, \code{fmCov} computes the covariance matrix for asset returns
+based on the fitted factor model
+
+An object of class \code{"tsfm"} is a list containing the following
+components:
+\item{asset.fit}{list of fitted objects for each asset. Each object is of
+class \code{lm} if \code{fit.method="OLS" or "DLS"}, class \code{lmRob} if
+the \code{fit.method="Robust"}, or class \code{lars} if
+\code{variable.selection="lars"}.}
+\item{alpha}{length-N vector of estimated alphas.}
+\item{beta}{N x K matrix of estimated betas.}
+\item{r2}{length-N vector of R-squared values.}
+\item{resid.sd}{length-N vector of residual standard deviations.}
+\item{fitted}{xts data object of fitted values; iff
+\code{variable.selection="lars"}}
+\item{call}{the matched function call.}
+\item{data}{xts data object containing the assets and factors.}
+\item{asset.names}{asset.names as input.}
+\item{factor.names}{factor.names as input.}
+\item{fit.method}{fit.method as input.}
+\item{variable.selection}{variable.selection as input.}
+Where N is the number of assets, K is the number of factors and T is the
+number of time periods.
+}
+\description{
+This is a wrapper function to fits a up/down market model for one
+or more asset returns or excess returns using time series regression.
+Users can choose between ordinary least squares-OLS, discounted least
+squares-DLS (or) robust regression. Several variable selection options
+including Stepwise, Subsets, Lars are available as well. An object of class
+\code{"tsfm"} is returned.
+}
+\details{
+Typically, factor models are fit using excess returns. \code{rf.name} gives
+the option to supply a risk free rate variable to subtract from each asset
+return and factor to compute excess returns.
+
+Estimation method "OLS" corresponds to ordinary least squares using
+\code{\link[stats]{lm}}, "DLS" is discounted least squares (weighted least
+squares with exponentially declining weights that sum to unity), and,
+"Robust" is robust regression (using \code{\link[robust]{lmRob}}).
+
+If \code{variable.selection="none"}, uses all the factors and performs no
+variable selection. Whereas, "stepwise" performs traditional stepwise
+LS or Robust regression (using \code{\link[stats]{step}} or
+\code{\link[robust]{step.lmRob}}), that starts from the initial set of
+factors and adds/subtracts factors only if the regression fit, as measured
+by the Bayesian Information Criterion (BIC) or Akaike Information Criterion
+(AIC), improves. And, "subsets" enables subsets selection using
+\code{\link[leaps]{regsubsets}}; chooses the best performing subset of any
+given size or within a range of subset sizes. Different methods such as
+exhaustive search (default), forward or backward stepwise, or sequential
+replacement can be employed.See \code{\link{fitTsfm.control}} for more
+details on the control arguments.
+
+\code{variable.selection="lars"} corresponds to least angle regression
+using \code{\link[lars]{lars}} with variants "lasso" (default), "lar",
+"stepwise" or "forward.stagewise". Note: If \code{variable.selection="lars"},
+\code{fit.method} will be ignored.
+
+
+\subsection{Data Processing}{
+
+Note about NAs: Before model fitting, incomplete cases are removed for
+every asset (return data combined with respective factors' return data)
+using \code{\link[stats]{na.omit}}. Otherwise, all observations in
+\code{data} are included.
+
+Note about \code{asset.names} and \code{factor.names}: Spaces in column
+names of \code{data} will be converted to periods as \code{fitTsfm} works
+with \code{xts} objects internally and colnames won't be left as they are.
+}
+}
+\examples{
+# load data from the database
+data(managers)
+
+# example: Up and down market factor model with OLS fit
+fitUpDn <- fitTsfmUpDn(asset.names=colnames(managers[,(1:6)]),mkt.name="SP500.TR",
+                       data=managers, fit.method="OLS",control=NULL)
+ # List object
+ fitUpDn
+
+ summary(fitUpDn$Up)
+ summary(fitUpDn$Dn)
+}
+\author{
+Yi-An Chen.
+}
+\references{
+Christopherson, J. A., Carino, D. R., & Ferson, W. E. (2009). Portfolio
+performance measurement and benchmarking. McGraw Hill Professional.
+
+Efron, B., Hastie, T., Johnstone, I., & Tibshirani, R. (2004). Least angle
+regression. The Annals of statistics, 32(2), 407-499.
+
+Hastie, T., Tibshirani, R., Friedman, J., Hastie, T., Friedman, J., &
+Tibshirani, R. (2009). The elements of statistical learning (Vol. 2, No. 1).
+New York: Springer.
+
+Henriksson, R. D., & Merton, R. C. (1981). On market timing and investment
+performance. II. Statistical procedures for evaluating forecasting skills.
+Journal of business, 513-533.
+
+Treynor, J., & Mazuy, K. (1966). Can mutual funds outguess the market.
+Harvard business review, 44(4), 131-136.
+}
+\seealso{
+The \code{tsfm} methods for generic functions:
+\code{\link{plot.tsfm}}, \code{\link{predict.tsfm}},
+\code{\link{print.tsfm}} and \code{\link{summary.tsfm}}.
+
+And, the following extractor functions: \code{\link[stats]{coef}},
+\code{\link[stats]{fitted}}, \code{\link[stats]{residuals}},
+\code{\link{fmCov}}, \code{\link{fmSdDecomp}}, \code{\link{fmVaRDecomp}}
+and \code{\link{fmEsDecomp}}.
+
+\code{\link{paFm}} for Performance Attribution.
+}
+



More information about the Returnanalytics-commits mailing list