More accurate message when torch is diverging.

R/PLNfit-class.R

@@ -146,7 +146,7 @@ PLNfit <- R6Class(
 
         ## Error message if objective diverges
         if (!is.finite(loss$item())) {
-          stop(sprintf("The ELBO diverged during the optimization procedure.\nConsider using:\n* a different optimizer (current optimizer: %s)\n* a smaller learning rate (current rate: %.3f)\nwith `control = PLN_param(config_optim = list(algorithm = ..., lr = ...))`",
+          stop(sprintf("The ELBO diverged during the optimization procedure.\nConsider using:\n* a different optimizer (current optimizer: %s)\n* a smaller learning rate (current rate: %.3f)\nwith `control = PLN_param(backend = "torch", config_optim = list(algorithm = ..., lr = ...))`",
                        config$algorithm, config$lr))
         }