Machine Learning : Few rarely shared trade secrets

If there are n number of instances in data, probability of'success' is 1/n and for the failure, its (n-1)/n. In the specific case of a bootstrap sample, the sample size b equals the number of instances n. Thus the probability of the instance being selected atleast once is 1-1/e 0.632 Grid search is computationally expensive as it checks for all the possible combinations of the parameters specified and evaluates on the same. Lets say if two parameters are A and B, and the possible ranges specified are 0-2 and 0-3 respectively; The possible combinations in the parameter space in case of grid search would be (0,0) (0,1) (0,2) (0,3) ...........(2,2) (2,3). Although grid search can be made to run in parallel, still the technique is not computationally very efficient .