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@ -9,11 +9,14 @@ from math import sqrt
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import json
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import os.path
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#from birdseye import eye
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# Get the directory of the current script to use in importing data
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# and exporting the model.
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basepath = os.path.dirname(os.path.realpath(__file__))
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# Load a CSV file. Definition of the function to read the csv and create dataset here
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#@eye
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def load_csv(filename):
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dataset = list()
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with open(filename, 'r') as file:
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@ -25,11 +28,13 @@ def load_csv(filename):
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return dataset
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# Convert string column to float - original dataset is in string format
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#@eye
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def str_column_to_float(dataset, column):
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for row in dataset:
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row[column] = float(row[column].strip())
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# Convert string column to integer / transforms classes 'mine' and 'rock' into 1 and 2
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#@eye
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def str_column_to_int(dataset, column):
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# extracts values of the classes of the dataset: array of all the mine, rock
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class_values = [row[column] for row in dataset]
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@ -49,6 +54,7 @@ def str_column_to_int(dataset, column):
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return lookup
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# Split a dataset into k folds
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#@eye
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def cross_validation_split(dataset, n_folds):
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# creates list
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dataset_split = list()
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@ -70,6 +76,7 @@ def cross_validation_split(dataset, n_folds):
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return dataset_split #return the dataset_split, a list of folds
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# Calculate accuracy percentage
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#@eye
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def accuracy_metric(actual, predicted):
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correct = 0
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# loops through index list which has length of actual classes
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@ -82,6 +89,7 @@ def accuracy_metric(actual, predicted):
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return correct / float(len(actual)) * 100.0
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# Evaluate an algorithm using a cross validation split
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#@eye
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def evaluate_algorithm(dataset, algorithm, n_folds, *args):
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# split dataset in n folds
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folds = cross_validation_split(dataset, n_folds)
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@ -120,6 +128,7 @@ def evaluate_algorithm(dataset, algorithm, n_folds, *args):
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# Split a dataset based on a feature and a feature value defined in build tree
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# just trying many times, benefitting from speed of computer
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#@eye
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def test_split(index, value, dataset):
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left, right = list(), list()
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for row in dataset:
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@ -134,6 +143,7 @@ def test_split(index, value, dataset):
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# Calculate the Gini index for a split dataset, using left/right og test split as groups
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# cfr calculating wealth distribution: https://en.wikipedia.org/wiki/Gini_coefficient
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#@eye
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def gini_index(groups, classes):
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# count all samples at split point (the dataset), converts it in a float in order to do divisions
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n_instances = float(sum([len(group) for group in groups]))
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@ -158,6 +168,7 @@ def gini_index(groups, classes):
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return gini
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# Select the best split point for a dataset
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#@eye
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def get_split(dataset, n_features):
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# takes last element of each row (class) and returns it as a row, as it is a set, it has only 2 values
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class_values = list(set(row[-1] for row in dataset))
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@ -187,6 +198,7 @@ def get_split(dataset, n_features):
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return {'index':b_index, 'value':b_value, 'groups':b_groups, 'gini':b_score}
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# Create a terminal node value = node at end of the tree = end leaf
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#@eye
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def to_terminal(group):
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# returns list of classes of group
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outcomes = [row[-1] for row in group]
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@ -195,6 +207,7 @@ def to_terminal(group):
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return max(set(outcomes), key=outcomes.count)
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# Counts the amount of unique values in a 'group' (rows in dataset)
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#@eye
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def count_unique_values (group):
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# Pick classes in the dataset, transform to a set
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# count amount of values
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@ -203,6 +216,7 @@ def count_unique_values (group):
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# Create child splits for a node or make terminals/end leafs
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# recursive function, it calls itself
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# node is dictionary returned by get_split (b_index, b_value, b_groups)
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#@eye
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def split(node, max_depth, min_size, n_features, depth):
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left, right = node['groups']
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del(node['groups'])
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@ -244,6 +258,7 @@ def split(node, max_depth, min_size, n_features, depth):
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# return no value because functions are working on the same dictionaries
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# Build a decision tree
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#@eye
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def build_tree(train, max_depth, min_size, n_features):
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# root of decision tree is defined by dictionary of index, value, 2 groups (left/right of the split)
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root = get_split(train, n_features)
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@ -255,6 +270,7 @@ def build_tree(train, max_depth, min_size, n_features):
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# Make a prediction with a decision tree
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# recursive function as well
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#@eye
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def predict(node, row):
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# node index = column feature, it looks up value for this feature for this row in dataset
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# compare feature value of row you're checking with feature value of node
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@ -278,6 +294,7 @@ def predict(node, row):
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# Create a random subsample from the dataset with replacement, ratio is called sample_size further on
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# This is called BOOTSTRAPPING: build new datasets from the original data, with the same number of rows
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# with replacement: after selecting the row we put it back into the data, so it can be selected twice or more
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#@eye
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def subsample(dataset, ratio):
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sample = list()
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# if it is smaller than 1, not all dataset is taken as sample - he uses the full dataset
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@ -288,6 +305,7 @@ def subsample(dataset, ratio):
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return sample
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# Make a prediction with a list of bagged trees
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#@eye
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def bagging_predict(trees, row):
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# asks the forest to predict class for every row in the test data, this gives list of votes
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predictions = [predict(tree, row) for tree in trees]
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@ -295,6 +313,7 @@ def bagging_predict(trees, row):
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return max(set(predictions), key=predictions.count)
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# Random Forest Algorithm
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#@eye
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def random_forest(train, test, max_depth, min_size, sample_size, n_trees, n_features, model_path=None):
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trees = list()
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for _ in range(n_trees):
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