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SRCS (version 1.0)

SRCSranks: Computes the ranks of all the algorithms from their (repeated) results measurements after grouping them by several factors combined simultaneosly.

Description

Computes the ranks of all the algorithms from their (repeated) results measurements after grouping them by several factors combined simultaneosly.

Usage

SRCSranks(data, params, target, performance, test = c("wilcoxon", "t",
  "tukeyHSD", "custom"), fun = NULL, correction = p.adjust.methods,
  alpha = 0.05, maximize = TRUE, ncores = 1, paired = FALSE, ...)

Arguments

data
A dataframe object containing (at least) two columns for the target factor and the performance measure Additional columns are aimed at grouping the problem configuration by (at most) 3 different factors.
params
A vector with the column names in data that define a problem configuration. If not already factor objects, those columns will be converted to factors inside the function (note this does not alter the ordering of the levels in case it was
target
Name of the target column of data. For each combination of the values of params, the ranks are obtained by comparing the repeated measurements of performance associated to each level of the target colum
performance
Name of the column of data containing the repeated performance measurements. If given a vector of strings, then a separate ranking will be computed for each of the elements, and no p-values, mean or stdev columns will be returned, just the r
test
The statistical test to be performed to compare the performance of every level of the target variable at each problem configuration.
fun
Function performing a custom statistical test, if test = "custom"; otherwise, this argument is ignored. The function must receive exactly two vectors (the first is a vector of real numbers and the second is a factor with the level to whic
correction
The p-value adjust method. Must be one of "holm", "hochberg", "hommel", "bonferroni", "BH", "BY", "fdr", "none" (defaults to "holm"). This parameter will be ignored if test = "tukeyHSD" as Tukey HSD incorporates its own correction procedure.
alpha
Significance threshold for pairwise comparisons. Defaults to 0.05.
maximize
Boolean indicating whether the higher the performance measure, the better (default), or vice-versa.
ncores
Number of physical CPUs available for computations. If ncores > 1, parallelization is achieved through the parallel package and is applied to the computation of ranks for more than one proble
paired
Boolean indicating whether samples in the same problem configuration, which only differ in the target value, and in the same relative position (row) within their respective target values are paired or not. Defaults to FALSE. This should be set to TRUE, f
...
Further arguments to be passed to the function fun that is called for every pairwise comparison.

Value

  • If length(performance) equals 1, an object of classes c("SRCS", "data.frame") with the following columns: - A set of columns with the same names as the params and target arguments. - Two columns called "mean" and "sd" containing the mean of the repeated peformance measurements for each problem configuration and the standard deviation. - One column named "rank" with the actual rank of each level of the target variable within that problem configuration. The lower the rank, the better the algorithm. - |target| additional columns containing the p-values resulting of the comparison between the algorithm and the rest for the same problem configuration, where |target| is the number of levels of the target variable. If length(performance) > 1 (let P = length(performance) for the explanation that follows), an object of classes c("SRCS","data.frame") with the following columns: - A set of columns with the same names as the params and target arguments. - One column per element of the performance vector, named "rank1", ..., "rankP", containing, for each performance measure, the rank of each level of the target variable within that problem configuration for that performance measure. The higher the rank, the better the algorithm.

See Also

plot.SRCS for a full working example of SRCSranks and plotting facilities. Also pairwise.wilcox.test, t.test, pairwise.t.test, TukeyHSD, p.adjust.methods