precrec (version 0.14.4)

mmdata: Reformat input data for performance evaluation calculation

Description

The mmdata function takes predicted scores and labels and returns an mdat object. The evalmod function takes an mdat object as input data to calculate evaluation measures.

Usage

mmdata(
  scores,
  labels,
  modnames = NULL,
  dsids = NULL,
  posclass = NULL,
  na_worst = TRUE,
  ties_method = "equiv",
  expd_first = NULL,
  mode = "rocprc",
  nfold_df = NULL,
  score_cols = NULL,
  lab_col = NULL,
  fold_col = NULL,
  ...
)

Value

The mmdata function returns an mdat object that contains formatted labels and score ranks. The object can be used as input data for the evalmod function.

Arguments

scores

A numeric dataset of predicted scores. It can be a vector, a matrix, an array, a data frame, or a list. The join_scores function can be useful to make scores with multiple datasets.

labels

A numeric, character, logical, or factor dataset of observed labels. It can be a vector, a matrix, an array, a data frame, or a list. The join_labels function can be useful to make labels with multiple datasets.

modnames

A character vector for the names of the models. The evalmod function automatically generates default names as "m1", "m2", "m3", and so on when it is NULL.

dsids

A numeric vector for test dataset IDs. The evalmod function automatically generates the default ID as 1 when it is NULL.

posclass

A scalar value to specify the label of positives in labels. It must be the same data type as labels. For example, posclass = -1 changes the positive label from 1 to -1 when labels contains 1 and -1. The positive label will be automatically detected when posclass is NULL.

na_worst

A Boolean value for controlling the treatment of NAs in scores.

TRUE

All NAs are treated as the worst scores

FALSE

All NAs are treated as the best scores

ties_method

A string for controlling ties in scores.

"equiv"

Ties are equivalently ranked

"first"

Ties are ranked in an increasing order as appeared

"random"

Ties are ranked in random order

expd_first

A string to indicate which of the two variables - model names or test dataset IDs should be expanded first when they are automatically generated.

"modnames"

Model names are expanded first. For example, The mmdata function generates modnames as c("m1", "m2") and dsids as c(1, 1) when two vectors are passed as input, and modnames and dsids are unspecified.

"dsids"

Test dataset IDs are expanded first. For example, The mmdata function generates modnames as c("m1", "m1") and dsids as c(1, 2) when two vectors are passed as input, and modnames and dsids are unspecified.

mode

A string that specifies the types of evaluation measures that the evalmod function calculates.

"rocprc"

ROC and Precision-Recall curves

"prcroc"

Same as above

"basic"

Normalized ranks vs. accuracy, error rate, specificity, sensitivity, precision, Matthews correlation coefficient, and F-score.

"aucroc"

Fast AUC(ROC) calculation with the U statistic

nfold_df

A data frame that contains at least one score column, label and fold columns.

score_cols

A character/numeric vector that specifies score columns of nfold_df.

lab_col

A number/string that specifies the label column of nfold_df.

fold_col

A number/string that specifies the fold column of nfold_df.

...

Not used by this method.

See Also

evalmod for calculation evaluation measures. join_scores and join_labels for formatting scores and labels with multiple datasets. format_nfold for creating n-fold cross validation dataset from data frame.

Examples

##################################################
### Single model & single test dataset
###

## Load a dataset with 10 positives and 10 negatives
data(P10N10)

## Generate mdat object
ssmdat1 <- mmdata(P10N10$scores, P10N10$labels)
ssmdat1
ssmdat2 <- mmdata(1:8, sample(c(0, 1), 8, replace = TRUE))
ssmdat2


##################################################
### Multiple models & single test dataset
###

## Create sample datasets with 100 positives and 100 negatives
samps <- create_sim_samples(1, 100, 100, "all")

## Multiple models & single test dataset
msmdat1 <- mmdata(samps[["scores"]], samps[["labels"]],
  modnames = samps[["modnames"]]
)
msmdat1

## Use join_scores and join_labels
s1 <- c(1, 2, 3, 4)
s2 <- c(5, 6, 7, 8)
scores <- join_scores(s1, s2)

l1 <- c(1, 0, 1, 1)
l2 <- c(1, 0, 1, 1)
labels <- join_labels(l1, l2)

msmdat2 <- mmdata(scores, labels, modnames = c("ms1", "ms2"))
msmdat2


##################################################
### Single model & multiple test datasets
###

## Create sample datasets with 100 positives and 100 negatives
samps <- create_sim_samples(10, 100, 100, "good_er")

## Single model & multiple test datasets
smmdat <- mmdata(samps[["scores"]], samps[["labels"]],
  modnames = samps[["modnames"]],
  dsids = samps[["dsids"]]
)
smmdat


##################################################
### Multiple models & multiple test datasets
###

## Create sample datasets with 100 positives and 100 negatives
samps <- create_sim_samples(10, 100, 100, "all")

## Multiple models & multiple test datasets
mmmdat <- mmdata(samps[["scores"]], samps[["labels"]],
  modnames = samps[["modnames"]],
  dsids = samps[["dsids"]]
)
mmmdat


##################################################
### N-fold cross validation datasets
###

## Load test data
data(M2N50F5)
head(M2N50F5)

## Speficy nessesary columns to create mdat
cvdat1 <- mmdata(
  nfold_df = M2N50F5, score_cols = c(1, 2),
  lab_col = 3, fold_col = 4,
  modnames = c("m1", "m2"), dsids = 1:5
)
cvdat1

## Use column names
cvdat2 <- mmdata(
  nfold_df = M2N50F5, score_cols = c("score1", "score2"),
  lab_col = "label", fold_col = "fold",
  modnames = c("m1", "m2"), dsids = 1:5
)
cvdat2