Warning message in predict_ligand_activities

[csangara]

When the regulatory potential of all genes in the gene set of interest is zero (for a certain ligand), this warning pops up:

Warning messages:
1: In evaluate_target_prediction(setting, ligand_target_matrix, ligands_position) :
all target gene probability score predictions have same value
2: In cor(prediction, response) : the standard deviation is zero
3: In cor(prediction, response, method = "s") :
the standard deviation is zero

In that case, the ligand should be removed from the output dataframe, along with a message to the user informing that the ligand has been removed.