added (hidden) explicit disable_line_search flag to allow user to for…

…ce disable line search in all cases

src/main/java/hex/glm/GLM2.java

@@ -64,6 +64,10 @@ public void setTweediePower(double pwr){
 
   @API(help="prior probability for y==1. To be used only for logistic regression iff the data has been sampled and the mean of response does not reflect reality.",filter=Default.class, importance = ParamImportance.EXPERT)
   protected double prior = -1; // -1 is magic value for default value which is mean(y) computed on the current dataset
+
+  @API(help="disable line search in all cases.",filter=Default.class, importance = ParamImportance.EXPERT, hide = true)
+  protected boolean disable_line_search = false; // -1 is magic value for default value which is mean(y) computed on the current dataset
+
   private double _iceptAdjust; // adjustment due to the prior
 
   @API(help = "validation folds", filter = Default.class, lmin=0, lmax=100, json=true, importance = ParamImportance.CRITICAL)
@@ -672,6 +676,8 @@ protected double l1norm(double[] beta){
   }
 //  protected boolean needLineSearch(final double [] beta,double objval, double step){
   protected boolean needLineSearch(final GLMIterationTask glmt) {
+    if(disable_line_search)
+      return false;
     if(_glm.family == Family.gaussian)
       return false;
     if(glmt._beta == null)
@@ -820,15 +826,7 @@ public void callback(final GLMIterationTask glmt2) {
         final double [] grad = glmt2.gradient(alpha[0],_currentLambda);
         if(Utils.hasNaNsOrInfs(grad)){
           _failedLineSearch = true;
-          if(!failedLineSearch) {
-            getCompleter().addToPendingCount(1);
-            checkKKTAndComplete(cc,glmt,glmt._beta,true);
-            LogInfo("Check KKT got NaNs. Taking previous solution");
-            return;
-          } else {
-            // TODO: add warning and break th lambda search? Or throw Exception?
-            LogInfo("got NaNs/Infs in gradient at lambda " + _currentLambda);
-          }
+          // TODO: add warning and break the lambda search? Or throw Exception?
         }
         glmt._val = glmt2._val;
         _lastResult = makeIterationInfo(_iter,glmt2,null,glmt2.gradient(alpha[0],0));