[Returnanalytics-commits] r2155 - pkg/PerformanceAnalytics/sandbox/Meucci/R
noreply at r-forge.r-project.org
noreply at r-forge.r-project.org
Fri Jul 13 12:25:48 CEST 2012
Author: mkshah
Date: 2012-07-13 12:25:48 +0200 (Fri, 13 Jul 2012)
New Revision: 2155
Modified:
pkg/PerformanceAnalytics/sandbox/Meucci/R/RobustBayesianAllocation.R
Log:
Correcting documentation mistakes
Modified: pkg/PerformanceAnalytics/sandbox/Meucci/R/RobustBayesianAllocation.R
===================================================================
--- pkg/PerformanceAnalytics/sandbox/Meucci/R/RobustBayesianAllocation.R 2012-07-13 10:24:08 UTC (rev 2154)
+++ pkg/PerformanceAnalytics/sandbox/Meucci/R/RobustBayesianAllocation.R 2012-07-13 10:25:48 UTC (rev 2155)
@@ -84,6 +84,10 @@
#' where each portfolio is equally distanced in return space. The function also returns the most robust
#' portfolio along the Bayesian efficient frontier
#'
+#' \deqn{ w_{rB}^{(i)} = argmax_{w \in C, w' \Sigma_{1} w \leq \gamma_{\Sigma}^{(i)} } \big\{w' \mu^{1} - \gamma _{\mu} \sqrt{w' \Sigma_{1} w} \big\}
+#' \\ \gamma_{\mu} \equiv \sqrt{ \frac{q_{\mu}^{2}}{T_{1}} \frac{v_{1}}{v_{1} - 2} }
+#' \\ \gamma_{\Sigma}^{(i)} \equiv \frac{v^{(i)}{ \frac{ \nu_{1}}{\nu_{1}+N+1} \sqrt{ \frac{2\nu_{1}^{2}q_{\Sigma}^{2}}{ (\nu_{1}+N+1)^{3} } } } } }
+#'
#' @param mean_post the posterior vector of means (after blending prior and sample data)
#' @param cov_post the posterior covariance matrix (after blending prior and sample data)
#' @param confidenceInPrior a numeric with the relative confidence in the prior vs. the sample data. A value of 2 indicates twice as much weight to assign to the prior vs. the sample data. Must be greater than or equal to zero
@@ -102,9 +106,6 @@
#' volatility: the expected volatility of each portfolo along the Bayesian efficient frontier
#' weights: the weights of each portfolo along the Bayesian efficient frontier
#'
-#' \deqn{ w_{rB}^{(i)} = argmax_{w \in C, w' \Sigma_{1} w \leq \gamma_{\Sigma}^{(i)} \big\{w' \mu^{1} - \gamma _{\mu} \sqrt{w' \Sigma_{1} w} \big\}
-#' \\ \gamma_{\mu} \equiv \sqrt{ \frac{q_{\mu}^{2}}{T_{1}} \frac{v_{1}}{v_{1} - 2} }
-#' \\ \gamma_{\Sigma}^{(i)} \equiv \frac{v^{(i)}{ \frac{ \nu_{1}}{\nu_{1}+N+1} \sqrt{ \frac{2\nu_{1}^{2}q_{\Sigma}^{2}}{ (\nu_{1}+N+1)^{3} } } } }
#' @references
#' A. Meucci - Robust Bayesian Allocation - See formula (19) - (21)
#' \url{ http://papers.ssrn.com/sol3/papers.cfm?abstract_id=681553 }
@@ -173,6 +174,10 @@
#' Constructs the partial confidence posterior based on prior (mean vector and covariance matrix) and a posterior
#' with a relative confidence in the prior vs. the sample data
#'
+#' \deqn{ T_{1} \equiv T_{0} + T
+#' \\ \mu_{1} \equiv \frac{1}{ T_{1} } \big( T_{0} \mu_{0} + T \hat{ \mu } \big)
+#' \\ \nu_{1} \equiv \nu_{0} + T
+#' \\ \Sigma_{1} \equiv \big( \nu_{0} \Sigma_{0} + T \hat{ \Sigma } + \frac{ \big(\mu_{0} - \hat{\mu} \big) \big(\mu_{0} - \hat{\mu} \big)' }{ \big( \frac{1}{T} + \frac{1}{T_{0} } \big) } }
#' @param mean the mean of the sample returns
#' @param cov the sample covariance matrix
#' @param mean_prior the prior for the mean returns
@@ -185,10 +190,6 @@
#' @return cov_post a covariance matrix the confidence weighted posterior covariance matrix of asset returns blended from the prior and sample covariance matrix
#' @return time_post a numeric
#' @return nu_pst a numeric
-#' \deqn{ T_{1} \equiv T_{0} + T
-#' \\ \mu_{1} \equiv \frac{1}{ T_{1} } \big( T_{0} \mu_{0} + T \hat{ \mu } \big)
-#' \\ \nu_{1} \equiv \nu_{0} + T
-#' \\ \Sigma_{1} \equiv \big( \nu_{0} \Sigma_{0} + T \hat{ \Sigma } + \frac{ \big(\mu_{0} - \hat{\mu} \big) \big(\mu_{0} - \hat{\mu} \big)' }{ \big( \frac{1}{T} + \frac{1}{T_{0} } \big) }
#' @author Ram Ahluwalia \email{ram@@wingedfootcapital.com}
#' @export
#' @references
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