post assignment 5

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# Description of Assignment 4
### Author: [Fotios Lygerakis](https://github.com/ligerfotis)
### Implement the Perceptron algorithm for classification of the Iris dataset.
* Use load_iris() from sklearn.datasets to load the Iris dataset.
* The Iris dataset is a multiclass classification dataset with 3 classes.
* The Iris dataset has 4 features and 150 samples.
* The Iris dataset is a balanced dataset with 50 samples per class.
* Split the dataset into train and test sets.
* Scale the features.
* Implement the Perceptron algorithm for classification.
* Use the unit step function as the activation function.
* Evaluate the model on the test set.
* Use accuracy_score() from sklearn.metrics to calculate the accuracy of the model.
* Do some hyperparameter tuning to improve the accuracy of the model.
* Try different values of the learning rate and the number of iterations.
* Print the accuracy of the model for different values of the learning rate and the number of iterations.
### Implement Non-linear feature transformation for regression of the Concrete Compressive Strength dataset.
* Use read_excel() from pandas to load the dataset.
* The Concrete Compressive Strength dataset
* is a regression dataset with 1 target variable.
* has 8 features and 1030 samples.
* has 1 target variable.
* Split the dataset into train and test sets.
* Scale the features.
* **Polynomial feature transformation**
* Implement the polynomial_features() function to transform the features.
* Use LinearRegression() from sklearn.linear_model to train a linear regression model.
* Evaluate the model on the test set.
* Use mean_squared_error() from sklearn.metrics to calculate the mean squared error of the model.
* Use r2_score() from sklearn.metrics to calculate the R2 score of the model.
* Train a linear regression model on the polynomial features varying the degree of the polynomial from 1 to 4.
* Evaluate the models trained on the polynomial features on the test set and compare the mean squared error of the models.
* Discuss the results in the report.
* **Radial Basis Function (RBF) feature transformation**
* Implement the rbf_features() function to transform the features.
* Use LinearRegression() from sklearn.linear_model to train a linear regression model.
* Evaluate the model on the test set.
* Use mean_squared_error() from sklearn.metrics to calculate the mean squared error of the model.
* Use r2_score() from sklearn.metrics to calculate the R2 score of the model.
* Train a linear regression model on the RBF features varying the gamma parameter from 0.1 to 10.
* Evaluate the models trained on the RBF features on the test set and compare the mean squared error of the models.
* Discuss the results in the report.
### **(Bonus)** Implement the Multilayer Perceptron algorithm (2 layers) for regression of the Concrete Compressive Strength dataset.
* Use train_test_split() from sklearn.model_selection to split the dataset into train and test sets.
* Use StandardScaler() from sklearn.preprocessing to scale the features.
* Implement the Multilayer Perceptron algorithm for regression.
* The Multilayer Perceptron algorithm is a neural network with 2 layers.
* Implement the forward propagation algorithm.
* Implement the backward propagation algorithm.
* Use the tanh function as the activation function for the hidden layer.
* Use the identity function as the activation function for the output layer.
* Evaluate the model on the test set.
* Do some hyperparameter tuning to improve the accuracy of the model.
* Try different values of the learning rate and the number of epochs.
* Plot the mean squared error of the model for different values of the learning rate and the number of epochs.
* Compare the performance of the Multilayer Perceptron algorithm with the Linear Regression algorithm.
* Use LinearRegression() from sklearn.linear_model to train a linear regression model.
* Use mean_squared_error() from sklearn.metrics to calculate the mean squared error of the linear regression model.
* Compare the mean squared error of the linear regression model with the mean squared error of the multilayer perceptron model.

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{
"cells": [
{
"cell_type": "markdown",
"source": [
"# Perceptron Algorithm for Classification of Iris Dataset"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 39,
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"(150, 4)\n",
"(150,)\n"
]
}
],
"source": [
"# load the iris dataset\n",
"from sklearn.datasets import load_iris\n",
"from sklearn.metrics import accuracy_score\n",
"import numpy as np\n",
"\n",
"iris = load_iris()\n",
"X = iris.data\n",
"y = iris.target"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Preprocess the data"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 40,
"outputs": [],
"source": [
"# Preprocess the data\n",
"from sklearn.model_selection import train_test_split\n",
"\n",
"# ToDo: split the data into train and test sets\n",
"X_train, X_test, y_train, y_test = None, None, None, None"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Define the perceptron algorithm"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 41,
"outputs": [],
"source": [
"# Define the perceptron algorithm\n",
"class Perceptron:\n",
" def __init__(self, learning_rate=0.01, n_iters=1000):\n",
" pass\n",
"\n",
" # define the fit function to train the model\n",
"\n",
" # define the predict function to predict labels\n",
"\n",
" def _unit_step_func(self, x):\n",
" pass"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Train the model"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 42,
"outputs": [],
"source": [
"# Train the model\n",
"p = Perceptron(learning_rate=0.01, n_iters=1000)\n",
"p.fit(X_train, y_train)\n",
"predictions_train = p.predict(X_train)\n",
"predictions = p.predict(X_test)"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Evaluate the model"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 44,
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Perceptron classification train accuracy 0.3416666666666667\n",
"Perceptron classification accuracy 0.3\n"
]
}
],
"source": [
"# evaluate train accuracy\n",
"print(\"Perceptron classification train accuracy\", accuracy_score(y_train, predictions_train))\n",
"print(\"Perceptron classification accuracy\", accuracy_score(y_test, predictions))"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Non-linear feature transformation on the concrete compressive strength dataset"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 45,
"outputs": [],
"source": [
"from itertools import combinations_with_replacement\n",
"\n",
"# ToDO: implement the polynomial_features() function\n",
"def polynomial_features(X, degree):\n",
" pass"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 46,
"outputs": [],
"source": [
"# Non-linear feature transformation\n",
"import pandas as pd\n",
"from sklearn.linear_model import LinearRegression\n",
"from sklearn.metrics import mean_squared_error, r2_score\n",
"\n",
"# load the concrete compressive strength dataset\n",
"df = pd.read_excel('Concrete_Data.xls')\n",
"\n",
"# ToDo: split the data into train and test sets\n",
"X_train, X_test, y_train, y_test = None, None, None, None\n",
"\n",
"# transform the features into second degree polynomial features\n",
"X_train_poly_custom = polynomial_features(X_train.values, degree=2)\n",
"X_test_poly_custom = polynomial_features(X_test.values, degree=2)\n"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Train the linear regression model"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 47,
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mean squared error (train poly custom): 64.55\n",
"Mean squared error (test poly custom): 58.28\n",
"Mean squared error (train): 110.66\n",
"Mean squared error (test): 95.98\n",
"R^2 (train poly custom): 0.77\n",
"R^2 (test poly custom): 0.77\n",
"R^2 (train): 0.61\n",
"R^2 (test): 0.63\n"
]
}
],
"source": [
"# Train the model\n",
"lr_poly_custom = LinearRegression()\n",
"lr = LinearRegression()\n",
"# fit the model\n",
"lr_poly_custom.fit(X_train_poly_custom, y_train)\n",
"lr.fit(X_train, y_train)\n",
"# predict values from the polynomial transformed features\n",
"predictions_poly_custom_train = lr_poly_custom.predict(X_train_poly_custom)\n",
"predictions_poly_custom = lr_poly_custom.predict(X_test_poly_custom)\n",
"# predict values from the original features\n",
"predictions_train = lr.predict(X_train)\n",
"predictions = lr.predict(X_test)\n",
"\n",
"# mean squared error\n",
"print(\"Mean squared error (train poly custom): {:.2f}\".format(mean_squared_error(y_train, predictions_poly_custom_train)))\n",
"print(\"Mean squared error (test poly custom): {:.2f}\".format(mean_squared_error(y_test, predictions_poly_custom)))\n",
"print(\"Mean squared error (train): {:.2f}\".format(mean_squared_error(y_train, predictions_train)))\n",
"print(\"Mean squared error (test): {:.2f}\".format(mean_squared_error(y_test, predictions)))\n",
"\n",
"# coefficient of determination (R^2)\n",
"print(\"R^2 (train poly custom): {:.2f}\".format(r2_score(y_train, predictions_poly_custom_train)))\n",
"print(\"R^2 (test poly custom): {:.2f}\".format(r2_score(y_test, predictions_poly_custom)))\n",
"print(\"R^2 (train): {:.2f}\".format(r2_score(y_train, predictions_train)))\n",
"print(\"R^2 (test): {:.2f}\".format(r2_score(y_test, predictions)))\n",
"\n"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"RBFs on the California Housing Prices dataset"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 48,
"outputs": [],
"source": [
"# ToDO: implement the rbf_kernel() function\n",
"def rbf_kernel(X, centers, gamma):\n",
" pass"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 49,
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Linear regression on original data:\n",
"MSE: 0.5558915986952443\n",
"R^2: 0.5757877060324508\n",
"\n",
"Linear regression on RBF-transformed data:\n",
"MSE: 0.37106446913117447\n",
"R^2: 0.7168330839511696\n"
]
}
],
"source": [
"from sklearn.datasets import fetch_california_housing\n",
"from sklearn.preprocessing import StandardScaler\n",
"from sklearn.model_selection import train_test_split\n",
"from sklearn.linear_model import LinearRegression\n",
"from sklearn.metrics import mean_squared_error, r2_score\n",
"\n",
"# Load the California Housing Prices dataset\n",
"data = fetch_california_housing()\n",
"X = data['data']\n",
"y = data['target']\n",
"\n",
"# ToDo: split the data into training and testing sets\n",
"\n",
"# ToDo: standardize the data\n",
"X_train_std = None\n",
"X_test_std = None\n",
"\n",
"# Choose the number of centroids and the RBF kernel width\n",
"num_centroids = 100\n",
"gamma = 0.1\n",
"\n",
"# Randomly select the centroids from the training set\n",
"np.random.seed(42)\n",
"idx = np.random.choice(X_train_std.shape[0], num_centroids, replace=False)\n",
"centroids = X_train_std[idx]\n",
"\n",
"# Compute the RBF features for the training and testing sets\n",
"rbf_train = rbf_kernel(X_train_std, centroids, gamma)\n",
"rbf_test = rbf_kernel(X_test_std, centroids, gamma)\n",
"\n",
"# Fit a linear regression model on the original and RBF-transformed data\n",
"linreg_orig = LinearRegression().fit(X_train_std, y_train)\n",
"linreg_rbf = LinearRegression().fit(rbf_train, y_train)\n",
"\n",
"# Evaluate the models on the testing set\n",
"y_pred_orig = linreg_orig.predict(X_test_std)\n",
"mse_orig = mean_squared_error(y_test, y_pred_orig)\n",
"r2_orig = r2_score(y_test, y_pred_orig)\n",
"\n",
"y_pred_rbf = linreg_rbf.predict(rbf_test)\n",
"mse_rbf = mean_squared_error(y_test, y_pred_rbf)\n",
"r2_rbf = r2_score(y_test, y_pred_rbf)\n",
"\n",
"# Print the results\n",
"print(\"Linear regression on original data:\")\n",
"print(\"MSE:\", mse_orig)\n",
"print(\"R^2:\", r2_orig)\n",
"\n",
"print(\"\\nLinear regression on RBF-transformed data:\")\n",
"print(\"MSE:\", mse_rbf)\n",
"print(\"R^2:\", r2_rbf)\n"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"# **(Bonus)** Multilayer Perceptron Algorithm for Regression of Concrete Compressive Strength Dataset"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Download the Concrete Compressive Strength Dataset from the UCI Machine Learning Repository."
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 50,
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"(1030, 9)\n"
]
}
],
"source": [
"# Download the Concrete Compressive Strength Dataset from the UCI Machine Learning Repository.\n",
"import pandas as pd\n",
"from sklearn.model_selection import train_test_split\n",
"from sklearn.preprocessing import StandardScaler\n",
"from sklearn.metrics import mean_squared_error\n",
"\n",
"import numpy as np\n",
"\n",
"# ToDo: load the dataset"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Preprocess the data"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 51,
"outputs": [],
"source": [
"# Preprocess the data\n",
"\n",
"# ToDo: normalize the features\n",
"\n",
"# ToDo: split the data into training and testing sets"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Define the multilayer perceptron algorithm"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 52,
"outputs": [],
"source": [
"# ToDo: Implement the functions in the MLP class\n",
"class MLP:\n",
" def __init__(self, input_dim, hidden_dim, output_dim, lr=0.01, epochs=1000):\n",
" pass\n"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Train the model"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 53,
"outputs": [],
"source": [
"# Create an instance of the MLP class\n",
"mlp = MLP(input_dim=X_train.shape[1], hidden_dim=10, output_dim=1, lr=0.01, epochs=1000)\n",
"# Train the model\n",
"mlp.fit(X_train, y_train)"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Evaluate the model"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 54,
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mean Squared Error: 36.8911071801165\n"
]
}
],
"source": [
"# Evaluate the model\n",
"y_pred = mlp.predict(X_test)\n",
"print(\"Mean Squared Error:\", mean_squared_error(y_test, y_pred))"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "markdown",
"source": [
"Compare the results with the linear regression model"
],
"metadata": {
"collapsed": false
}
},
{
"cell_type": "code",
"execution_count": 19,
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mean Squared Error: 95.97548435337708\n"
]
}
],
"source": [
"# ToDo: fit a linear regression model on the training data"
],
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