Solved by teja in post #3 
              
              
                Thank you @ptrblck for your suggestion, this is how I tried to split the validation data into two parts, and it worked, I hope it is ok. 
indices = list(range(83258)) # 83258 is the total validation samples
np.random.shuffle(indices)
    
val1=indices[:41629]
val2=indices[41629:]
sampler1=SubsetRand…