PR

DESCRIPTION

@@ -1,19 +1,18 @@
 Package: implied
 Type: Package
-Title: Convert Bookmaker Odds to Probabilities
-Version: 0.3.0
+Title: Convert Between Bookmaker Odds and Probabilities
+Version: 0.5
 Author: Jonas Christoffer Lindstrøm
 Maintainer: Jonas Christoffer Lindstrøm <jonaslindstrom88@gmail.com>
-Description: Convert bookmaker odds into proper probabilities. Seven different
+Description: Convert between bookmaker odds and probabilities. Eight different
     algorithms are available, including basic normalization, Shin's method 
     (Hyun Song Shin, (1992) <doi:10.2307/2234526>), and others.
 License: GPL-3
 Encoding: UTF-8
-LazyData: true
-RoxygenNote: 7.0.2
+RoxygenNote: 7.1.2
 Suggests: testthat (>= 2.0.1), knitr, rmarkdown
 VignetteBuilder: knitr
 NeedsCompilation: no
-Packaged: 2020-04-18 20:55:05 UTC; jonas
+Packaged: 2023-06-11 18:14:04 UTC; Jonas Christoffer
 Repository: CRAN
-Date/Publication: 2020-04-19 00:10:02 UTC
+Date/Publication: 2023-06-11 19:50:02 UTC

MD5

@@ -1,13 +1,19 @@
-e1c144d5150fe622cb088097d29ffaf7 *DESCRIPTION
-75b5ea970258de895ca96f3181b8d226 *NAMESPACE
-31329041bcfc965c10df22f350a6374d *NEWS.md
-55da476a7af11123d0eb8ec856e198b1 *R/implied_probabilities.R
+ed8a77ffdb40f140f6980f99e45a2f4c *DESCRIPTION
+d32331dc3ccbe103bf204525d1ff82dd *NAMESPACE
+5175f26d9c3bc4f740a5496d4660b7dc *NEWS.md
+8a73301aac80eaec88540c50efe4ee62 *R/implied_odds.R
+078d65c0870d882ebf7e890a836385cb *R/implied_probabilities.R
 c71d10f8db03d579fa1c0c6e76959a7f *R/zzz.R
-36fd139695e3baa1e55cba43a4853575 *build/vignette.rds
-aa3c1d34d43a0625c11e32d252ef5614 *inst/doc/introduction.R
-71fa897a314a5fac9c5cdbe6693f7ab0 *inst/doc/introduction.Rmd
-38b8657a46510b13acf377dfb886952c *inst/doc/introduction.html
-4bddfd68c8d5de61751fe82910dd1e27 *man/implied_probabilities.Rd
+e8bc7681acd8e612eaab83ac4fc77076 *build/vignette.rds
+9f3d124e6bbd9e052fef01e69d83ddba *inst/doc/Troubleshooting.R
+111e67fb6ca9478877c5ab056380f1e0 *inst/doc/Troubleshooting.Rmd
+cce10b1137bac370165e60c135599a9e *inst/doc/Troubleshooting.html
+b95af5b478898d4e0b06423d0f827ad9 *inst/doc/introduction.R
+8d8c5b2afdcae2048b42605d42ef2a70 *inst/doc/introduction.Rmd
+f697ee1b3f19b8d8b4a085a46d84f176 *inst/doc/introduction.html
+32101c917ca72f6d3e0d880a57a802c7 *man/implied_odds.Rd
+2f28bbc547f1a4eb90cbfa92ac2a2cff *man/implied_probabilities.Rd
 bc77ebadaa37370915e00adac9036b01 *tests/testthat.R
-970cea6265a2285a1865d398a855dd4a *tests/testthat/test_1.R
-71fa897a314a5fac9c5cdbe6693f7ab0 *vignettes/introduction.Rmd
+60e9727bd36a19cbb31f8324f0ea3ac1 *tests/testthat/test_1.R
+111e67fb6ca9478877c5ab056380f1e0 *vignettes/Troubleshooting.Rmd
+8d8c5b2afdcae2048b42605d42ef2a70 *vignettes/introduction.Rmd

NAMESPACE

@@ -1,3 +1,4 @@
 # Generated by roxygen2: do not edit by hand
 
+export(implied_odds)
 export(implied_probabilities)

NEWS.md

@@ -1,7 +1,33 @@
-# implied Version 0.3.0
-* A new algorithm for Shin's method is included.
-* Small bugfix for when Shin's method fails and produces NA's. Instead of crashing, it now raises a warning and flags the result as problematic.  
-
-
-# implied Version 0.2.5
-* First version on CRAN.
+
+
+# implied Version 0.5
+* Can now convert odds to probabilities that should sum to other values than 1, using the target_probability argument in implied_probabilities().
+* New vignette 'Troubleshooting'.
+* Introduction vignette updated with how to use the new target_probability option.
+* New option 'uniroot_options' in implied_probabilities, to better control the uniroot solver.
+* Fixed many spelling errors in the documentation.
+
+
+# implied Version 0.4.1
+* Small change to how the 'jsd' method in implied_probabilities() works, so that it works in some cases where it used to fail.
+* Fixed a link in the Introduction vignette.
+
+
+# implied Version 0.4.0
+* New function implied_odds(), that converts probabilities to odds with a given margin.
+* New method = 'jsd' in implied_probabilities(). Check the introductory vignette for more information.
+
+# implied Version 0.3.2
+* Fixed wrong formula for the WPO method in the introduction vignette.
+
+# implied Version 0.3.1
+* Raises error if the inverse odds sum to less than 1.
+* NA's will be returned if there are NA's in the input odds.
+
+# implied Version 0.3.0
+* A new algorithm for Shin's method is included.
+* Small bugfix for when Shin's method fails and produces NA's. Instead of crashing, it now raises a warning and flags the result as problematic.  
+
+
+# implied Version 0.2.5
+* First version on CRAN.

R/implied_odds.R

@@ -0,0 +1,248 @@
+
+
+
+# The functions xx_func_o(coef, probs) transforms proper probabilities (that sum to 1)
+# into improper probabilities as a function of the input coefficient.
+# The corresponding functions xx_o_solvefor(coef, probs, margin) are used
+# with uniroot to find the coefficient that makes the transformed probabilities
+# sum to the desired margin.
+
+# Transform the probabilities using the Shin's method,
+# for a given value of the odds ratio cc.
+shin_func_o <- function(zz, probs, grossmargin=NULL){
+
+  # Eq. 5 in Shin 1993.
+  yy <- sqrt((zz*probs) + ((1-zz)*probs^2))
+  res <- yy * sum(yy)
+
+  if (!is.null(grossmargin)){
+    # Eq. 14 in in Fingleton & Waldron 1999
+    res <- res / (1 - grossmargin)
+  }
+
+  return(res)
+}
+
+# the condition that the sum of the probabilites must sum to 1.
+# Used with uniroot.
+shin_o_solvefor <- function(zz, probs, margin, grossmargin=NULL){
+  tmp <- shin_func_o(zz, probs, grossmargin)
+  sum(tmp) - (1 + margin)
+}
+
+
+# Transform the probabilities using the odds ratio method,
+# for a given value of the odds ratio cc.
+or_func_o <- function(cc, probs){
+  or_probs <- cc * probs
+  or_probs / (1 - probs + or_probs)
+}
+
+# The condition that the sum of the transformed probabilites
+# must sum to 1 + margin.
+or_o_solvefor <- function(cc, probs, margin){
+  tmp <- or_func_o(cc, probs)
+  sum(tmp) - (1 + margin)
+}
+
+
+# Transform the probabilities using the power method.
+pwr_func_o <- function(nn, probs){
+  probs^(nn)
+}
+
+# The condition that the sum of the transformed probabilites
+# must sum to 1 + margin.
+pwr_o_solvefor <- function(nn, probs, margin){
+  tmp <- pwr_func_o(nn, probs)
+  sum(tmp) - (1 + margin)
+}
+
+
+
+#' Implied odds with added margin from probabilities.
+#'
+#' This functions converts probabilities to odds in decimal format, while adding overround.
+#' The function does the inverse of what the function \code{\link{implied_probabilities}} does.
+#'
+#' @param probabilities A matrix or numeric of probabilities, where each column is an outcome.
+#' @param method A string giving the method to use. Valid methods are 'basic', 'shin', 'bb', 'wpo', 'or', 'power' or 'additive'.
+#' @param margin numeric. How large margin (aka overround) should be added to the probabilities.
+#' @param grossmargin Numeric. Must be 0 or greater. See the details.
+#' @param normalize Logical. If TRUE (default), scale the input probabilites to sum to 1.
+#'
+#' @return A named list. The first component is named 'odds' and contain a matrix of
+#' implied odds. The second depends on the method used to compute the probabilities.
+#'
+#' @export
+implied_odds <- function(probabilities, method = 'basic', margin = 0,
+                         grossmargin = NULL, normalize=TRUE){
+
+  stopifnot(length(method) == 1,
+            length(margin) == 1,
+            tolower(method) %in% c('basic', 'shin', 'bb', 'wpo', 'or', 'power', 'additive'),
+            all(probabilities >= 0, na.rm=TRUE))
+
+
+
+  if (!is.matrix(probabilities)){
+
+    if ('data.frame' %in% class(probabilities)){
+      probabilities <- as.matrix(probabilities)
+    } else {
+      probabilities <- matrix(probabilities, nrow=1,
+                     dimnames = list(NULL, names(probabilities)))
+    }
+  }
+
+  # Make sure the probabilities sum to exactly 1.
+  if (normalize){
+    probabilities  <- probabilities / rowSums(probabilities)
+  }
+
+  # Prepare the list that will be returned.
+  out <- vector(mode='list', length=1)
+  names(out) <- c('odds')
+
+  # Some useful quantities
+  n_probs <- nrow(probabilities)
+  n_outcomes <- ncol(probabilities)
+
+  # Missing values
+  missing_idx <- apply(probabilities, MARGIN = 1,
+                       FUN = function(x) any(is.na(x)))
+
+  # inverted_probs <- 1 / probabilities
+
+  if (method == 'basic'){
+
+    out$odds <- 1 / (probabilities * (1 + margin))
+
+  } else if (method == 'shin'){
+
+    odds <- matrix(nrow=n_probs, ncol=n_outcomes)
+    zz <- numeric(n_probs)
+
+    for (ii in 1:n_probs){
+
+      # Skip rows with missing values.
+      if (missing_idx[ii] == TRUE){
+        next
+      }
+
+      if (margin != 0){
+        res <- stats::uniroot(f=shin_o_solvefor, interval =  c(0, 0.4),
+                              probs=probabilities[ii,],
+                              margin = margin, grossmargin = grossmargin)
+        zz[ii] <- res$root
+      } else {
+        zz[ii] <- 0
+      }
+
+      odds[ii,] <- 1 / shin_func_o(zz=zz[ii], probs = probabilities[ii,], grossmargin = grossmargin)
+    }
+
+    out$odds <- odds
+    out$zvalues <- zz
+
+  } else if (method == 'bb'){
+
+    if (is.null(grossmargin)){
+      grossmargin <- 0
+    } else {
+      stopifnot(grossmargin >= 0,
+                length(grossmargin) == 1)
+    }
+
+    zz <- (((1-grossmargin)*(1 + margin)) - 1) / (n_outcomes-1)
+    out$odds <- 1 / ((1+margin) * (((probabilities*(1-zz)) + zz) / ((n_outcomes-1)*zz + 1)))
+
+    out$zvalues <- zz
+
+  } else if (method == 'wpo'){
+    # Margin Weights Proportional to the Odds.
+    # Method from the Wisdom of the Crowds pdf.
+    invprob <- 1 / probabilities
+    out$specific_margins <- (margin * invprob) / n_outcomes
+    out$odds <- invprob / (1 + out$specific_margins)
+
+  } else if (method == 'or'){
+
+    odds <- matrix(nrow=n_probs, ncol=n_outcomes)
+    odds_ratios <- numeric(n_probs)
+
+    for (ii in 1:n_probs){
+
+      # Skip rows with missing values.
+      if (missing_idx[ii] == TRUE){
+        next
+      }
+
+      if (margin != 0){
+        res <- stats::uniroot(f=or_o_solvefor, interval = c(0.05, 5),
+                              probs=probabilities[ii,], margin = margin)
+        odds_ratios[ii] <- res$root
+      } else {
+        odds_ratios[ii] <- 1
+      }
+
+      odds[ii,] <- 1 / or_func_o(cc=odds_ratios[ii], probs = probabilities[ii,])
+    }
+
+    out$odds <- odds
+    out$odds_ratios <- odds_ratios
+
+  } else if (method == 'power'){
+
+    odds <- matrix(nrow=n_probs, ncol=n_outcomes)
+    exponents <- numeric(n_probs)
+
+    for (ii in 1:n_probs){
+
+      # Skip rows with missing values.
+      if (missing_idx[ii] == TRUE){
+        next
+      }
+
+      if (margin != 0){
+        res <- stats::uniroot(f=pwr_o_solvefor, interval = c(0.0001, 1.1),
+                              probs=probabilities[ii,], margin = margin)
+        exponents[ii] <- res$root
+      } else {
+        exponents[ii] <- 1
+      }
+
+      odds[ii,] <- 1 / pwr_func_o(nn=exponents[ii], probs = probabilities[ii,])
+    }
+
+    out$odds <- odds
+    out$exponents <- exponents
+
+  } else if (method == 'additive'){
+
+    odds <- matrix(nrow=n_probs, ncol=n_outcomes)
+
+    for (ii in 1:n_probs){
+
+      # Skip rows with missing values.
+      if (missing_idx[ii] == TRUE){
+        next
+      }
+
+      odds[ii,] <- 1 / (probabilities[ii,] + (margin / n_outcomes))
+    }
+
+    out$odds <- odds
+
+  }
+
+  # Make sure the matrix of implied probabilities has column names.
+  if (!is.null(colnames(probabilities))){
+    colnames(out$odds) <- colnames(probabilities)
+  }
+
+
+  return(out)
+
+
+}