update sdm methods: add gbm2 for Boosted Regression Trees and refine svm2 for better classification

Author: elgabbas

R/mod_ssdm_helpers.R

@@ -1596,8 +1596,8 @@ sdm_model_settings <- function() {
     glmnet2 = list(maxit = 100000L),
     mars = list(),
     mars2 = list(),
-    gbm = list(n.trees = 2000L, interaction.depth = 4L),
-    gbm2 = list(n.trees = 2000L, interaction.depth = 4L),
+    gbm = list(n.trees = 4000L, interaction.depth = 4L),
+    gbm2 = list(n.trees = 4000L, interaction.depth = 4L),
     rf = list(ntree = 1000L, nodesize = 5L),
     rf2 = list(ntree = 1000L, nodesize = 5L),
     ranger = list(