diff --git a/CREClass.m b/CREClass.m
index 1611f1c..22c4c46 100644
--- a/CREClass.m
+++ b/CREClass.m
@@ -104,7 +104,13 @@ classdef CREClass < handle
             LogFC=log(FC);
             LogFC(~isfinite(LogFC))=0;%the log of 0 is -inf. however in Fc.*logFc it should end up as 0. to avoid conflicts removing the -inf
             if any(isnan(FC));error('something went wrong');end %catch a posible error. 
-            obj.CRE=-transpose(dl)*(FC.*LogFC)./(transpose(dl)*FC); %CRE zografos 
+            if transpose(dl)*FC==0; 
+                %if only one value in the most left bin in the distribution I may get a 0 divided by 0
+                %as the CRE of a delta function is 0, enforce this outcome
+                obj.CRE=0;
+            else
+                obj.CRE=-transpose(dl)*(FC.*LogFC)./(transpose(dl)*FC); %CRE zografos
+            end
             %% get the RB
             dl(FC>0.5)=0; %set the weight for all in the histogram to the left side (i.e. <p50) to 0
             CRE_Med_Inf=-transpose(dl)*(FC.*LogFC)./(transpose(dl)*FC); %CRE zografos 
diff --git a/TestCREClass.m b/TestCREClass.m
index 91c4a72..2a2f0bd 100644
--- a/TestCREClass.m
+++ b/TestCREClass.m
@@ -1,5 +1,5 @@
 S=CREClass;
-S.Data=randn(100000,1);
+S.Data=randn(100,1);
 S.nBin=(1000);
 %% use histogram
 S.UseHistProxy=true;
@@ -13,10 +13,16 @@ std(S.Data)
 %% multiply S
 S.Data=100*S.Data;
 S.UseHistProxy=true;
-S.Calc
+S.Calc;
 S
 std(S.Data)
 %% ones again the "new" way
 S.UseHistProxy=false;
-S.Calc
-S
\ No newline at end of file
+S.Calc;
+S
+%% Test CCRE class
+CS=CCREClass;
+CS.Data=randn(100,1);
+CS.nBin=10;
+CS.DataRef=randn(100,1);
+CS.nBinRef=10;
\ No newline at end of file