Created
March 21, 2017 18:56
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Predicting wine quality using a random forest classifier in SparkR
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library(readr) | |
library(dplyr) | |
url <- "https://archive.ics.uci.edu/ml/machine-learning-databases/wine-quality/winequality-white.csv" | |
df <- | |
read_delim(url, delim = ";") %>% | |
dplyr::mutate(taste = as.factor(ifelse(quality < 6, "bad", ifelse(quality > 6, "good", "average")))) %>% | |
dplyr::select(-quality) | |
df <- dplyr::mutate(df, id = as.integer(rownames(df))) | |
print(df, n=25) | |
table(df$taste) | |
Sys.setenv(SPARK_HOME="/home/andrew/spark-2.1.0-bin-hadoop2.7") | |
library(SparkR, lib.loc=c(file.path(Sys.getenv("SPARK_HOME"), "R", "lib"))) | |
sparkR.session(master="local[*]") | |
ddf <- createDataFrame(df) | |
seed <- 12345 | |
training_ddf <- sample(ddf, withReplacement=FALSE, fraction=0.7, seed=seed) | |
test_ddf <- except(ddf, training_ddf) | |
model <- spark.randomForest(training_ddf, taste ~ ., type="classification", seed=seed) | |
summary(model) | |
predictions <- predict(model, test_ddf) | |
prediction_df <- collect(select(predictions, "id", "prediction")) | |
actual_vs_predicted <- | |
dplyr::inner_join(df, prediction_df, "id") %>% | |
dplyr::select(id, actual = taste, predicted = prediction) | |
mean(actual_vs_predicted$actual == actual_vs_predicted$predicted) | |
table(actual_vs_predicted$actual, actual_vs_predicted$predicted) | |
model_file_path <- "/home/andrew/wine_random_forest_model" | |
write.ml(model, model_file_path) | |
new_model <- read.ml(model_file_path) | |
summary(new_model) |
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