26 lines
804 B
R
Executable File
26 lines
804 B
R
Executable File
require(xgboost)
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data(iris)
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iris[,5] <- as.numeric(iris[,5]=='setosa')
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iris <- as.matrix(iris)
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set.seed(20)
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test_ind <- sample(1:nrow(iris),50)
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train_ind <- setdiff(1:nrow(iris),test_ind)
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dtrain <- xgb.DMatrix(iris[train_ind,1:4], label=iris[train_ind,5])
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dtest <- xgb.DMatrix(iris[test_ind,1:4], label=iris[test_ind,5])
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param <- list(max_depth=2,eta=1,silent=1,objective='binary:logistic')
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watchlist <- list(eval = dtest, train = dtrain)
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num_round = 2
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bst = xgb.train(param, dtrain, num_round, watchlist)
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cat('start testing prediction from first n trees\n')
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labels <- getinfo(dtest,'label')
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ypred1 = predict(bst, dtest, ntreelimit=1)
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ypred2 = predict(bst, dtest)
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cat('error of ypred1=', mean(as.numeric(ypred1>0.5)!=labels),'\n')
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cat('error of ypred2=', mean(as.numeric(ypred2>0.5)!=labels),'\n')
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