Plot PLSDA predictions
Examples
#' # Data analysis for a table of integrated peaks
## Generate an artificial nmr_dataset_peak_table:
### Generate artificial metadata:
num_samples <- 32 # use an even number in this example
num_peaks <- 20
metadata <- data.frame(
NMRExperiment = as.character(1:num_samples),
Condition = rep(c("A", "B"), times = num_samples / 2)
)
### The matrix with peaks
peak_means <- runif(n = num_peaks, min = 300, max = 600)
peak_sd <- runif(n = num_peaks, min = 30, max = 60)
peak_matrix <- mapply(function(mu, sd) rnorm(num_samples, mu, sd),
mu = peak_means, sd = peak_sd
)
colnames(peak_matrix) <- paste0("Peak", 1:num_peaks)
## Artificial differences depending on the condition:
peak_matrix[metadata$Condition == "A", "Peak2"] <-
peak_matrix[metadata$Condition == "A", "Peak2"] + 70
peak_matrix[metadata$Condition == "A", "Peak6"] <-
peak_matrix[metadata$Condition == "A", "Peak6"] - 60
### The nmr_dataset_peak_table
peak_table <- new_nmr_dataset_peak_table(
peak_table = peak_matrix,
metadata = list(external = metadata)
)
## We will use a double cross validation, splitting the samples with random
## subsampling both in the external and internal validation.
## The classification model will be a PLSDA, exploring at maximum 3 latent
## variables.
## The best model will be selected based on the area under the ROC curve
methodology <- plsda_auroc_vip_method(ncomp = 1)
model <- nmr_data_analysis(
peak_table,
y_column = "Condition",
identity_column = NULL,
external_val = list(iterations = 1, test_size = 0.25),
internal_val = list(iterations = 1, test_size = 0.25),
data_analysis_method = methodology
)
# plot_plsda_samples(model$outer_cv_results[[1]]$model)