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240 lines
6.9 KiB
C++
240 lines
6.9 KiB
C++
//
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// LinReg.cpp
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//
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// Created by Marc Melikyan on 10/2/20.
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//
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#include "lin_reg.h"
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#include "../cost/cost.h"
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#include "../lin_alg/lin_alg.h"
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#include "../regularization/reg.h"
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#include "../stat/stat.h"
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#include "../utilities/utilities.h"
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#include <cmath>
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#include <iostream>
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#include <random>
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LinReg::LinReg(std::vector<std::vector<double>> inputSet, std::vector<double> outputSet, std::string reg, double lambda, double alpha) :
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inputSet(inputSet), outputSet(outputSet), n(inputSet.size()), k(inputSet[0].size()), reg(reg), lambda(lambda), alpha(alpha) {
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y_hat.resize(n);
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weights = Utilities::weightInitialization(k);
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bias = Utilities::biasInitialization();
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}
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std::vector<double> LinReg::modelSetTest(std::vector<std::vector<double>> X) {
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return Evaluate(X);
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}
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double LinReg::modelTest(std::vector<double> x) {
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return Evaluate(x);
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}
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void LinReg::NewtonRaphson(double learning_rate, int max_epoch, bool UI) {
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MLPPLinAlg alg;
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Reg regularization;
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double cost_prev = 0;
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int epoch = 1;
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forwardPass();
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while (true) {
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cost_prev = Cost(y_hat, outputSet);
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std::vector<double> error = alg.subtraction(y_hat, outputSet);
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// Calculating the weight gradients (2nd derivative)
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std::vector<double> first_derivative = alg.mat_vec_mult(alg.transpose(inputSet), error);
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std::vector<std::vector<double>> second_derivative = alg.matmult(alg.transpose(inputSet), inputSet);
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weights = alg.subtraction(weights, alg.scalarMultiply(learning_rate / n, alg.mat_vec_mult(alg.transpose(alg.inverse(second_derivative)), first_derivative)));
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weights = regularization.regWeights(weights, lambda, alpha, reg);
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// Calculating the bias gradients (2nd derivative)
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bias -= learning_rate * alg.sum_elements(error) / n; // We keep this the same. The 2nd derivative is just [1].
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forwardPass();
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if (UI) {
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Utilities::CostInfo(epoch, cost_prev, Cost(y_hat, outputSet));
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Utilities::UI(weights, bias);
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}
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epoch++;
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if (epoch > max_epoch) {
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break;
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}
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}
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}
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void LinReg::gradientDescent(double learning_rate, int max_epoch, bool UI) {
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MLPPLinAlg alg;
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Reg regularization;
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double cost_prev = 0;
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int epoch = 1;
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forwardPass();
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while (true) {
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cost_prev = Cost(y_hat, outputSet);
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std::vector<double> error = alg.subtraction(y_hat, outputSet);
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// Calculating the weight gradients
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weights = alg.subtraction(weights, alg.scalarMultiply(learning_rate / n, alg.mat_vec_mult(alg.transpose(inputSet), error)));
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weights = regularization.regWeights(weights, lambda, alpha, reg);
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// Calculating the bias gradients
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bias -= learning_rate * alg.sum_elements(error) / n;
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forwardPass();
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if (UI) {
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Utilities::CostInfo(epoch, cost_prev, Cost(y_hat, outputSet));
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Utilities::UI(weights, bias);
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}
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epoch++;
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if (epoch > max_epoch) {
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break;
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}
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}
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}
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void LinReg::SGD(double learning_rate, int max_epoch, bool UI) {
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MLPPLinAlg alg;
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Reg regularization;
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double cost_prev = 0;
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int epoch = 1;
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while (true) {
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std::random_device rd;
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std::default_random_engine generator(rd());
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std::uniform_int_distribution<int> distribution(0, int(n - 1));
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int outputIndex = distribution(generator);
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double y_hat = Evaluate(inputSet[outputIndex]);
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cost_prev = Cost({ y_hat }, { outputSet[outputIndex] });
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double error = y_hat - outputSet[outputIndex];
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// Weight updation
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weights = alg.subtraction(weights, alg.scalarMultiply(learning_rate * error, inputSet[outputIndex]));
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weights = regularization.regWeights(weights, lambda, alpha, reg);
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// Bias updation
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bias -= learning_rate * error;
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y_hat = Evaluate({ inputSet[outputIndex] });
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if (UI) {
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Utilities::CostInfo(epoch, cost_prev, Cost({ y_hat }, { outputSet[outputIndex] }));
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Utilities::UI(weights, bias);
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}
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epoch++;
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if (epoch > max_epoch) {
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break;
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}
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}
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forwardPass();
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}
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void LinReg::MBGD(double learning_rate, int max_epoch, int mini_batch_size, bool UI) {
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MLPPLinAlg alg;
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Reg regularization;
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double cost_prev = 0;
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int epoch = 1;
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// Creating the mini-batches
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int n_mini_batch = n / mini_batch_size;
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auto [inputMiniBatches, outputMiniBatches] = Utilities::createMiniBatches(inputSet, outputSet, n_mini_batch);
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while (true) {
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for (int i = 0; i < n_mini_batch; i++) {
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std::vector<double> y_hat = Evaluate(inputMiniBatches[i]);
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cost_prev = Cost(y_hat, outputMiniBatches[i]);
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std::vector<double> error = alg.subtraction(y_hat, outputMiniBatches[i]);
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// Calculating the weight gradients
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weights = alg.subtraction(weights, alg.scalarMultiply(learning_rate / outputMiniBatches[i].size(), alg.mat_vec_mult(alg.transpose(inputMiniBatches[i]), error)));
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weights = regularization.regWeights(weights, lambda, alpha, reg);
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// Calculating the bias gradients
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bias -= learning_rate * alg.sum_elements(error) / outputMiniBatches[i].size();
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y_hat = Evaluate(inputMiniBatches[i]);
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if (UI) {
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Utilities::CostInfo(epoch, cost_prev, Cost(y_hat, outputMiniBatches[i]));
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Utilities::UI(weights, bias);
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}
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}
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epoch++;
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if (epoch > max_epoch) {
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break;
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}
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}
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forwardPass();
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}
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void LinReg::normalEquation() {
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MLPPLinAlg alg;
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Stat stat;
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std::vector<double> x_means;
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std::vector<std::vector<double>> inputSetT = alg.transpose(inputSet);
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x_means.resize(inputSetT.size());
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for (int i = 0; i < inputSetT.size(); i++) {
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x_means[i] = (stat.mean(inputSetT[i]));
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}
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//try {
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std::vector<double> temp;
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temp.resize(k);
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temp = alg.mat_vec_mult(alg.inverse(alg.matmult(alg.transpose(inputSet), inputSet)), alg.mat_vec_mult(alg.transpose(inputSet), outputSet));
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if (std::isnan(temp[0])) {
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//throw 99;
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//TODO ERR_FAIL_COND
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} else {
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if (reg == "Ridge") {
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weights = alg.mat_vec_mult(alg.inverse(alg.addition(alg.matmult(alg.transpose(inputSet), inputSet), alg.scalarMultiply(lambda, alg.identity(k)))), alg.mat_vec_mult(alg.transpose(inputSet), outputSet));
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} else {
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weights = alg.mat_vec_mult(alg.inverse(alg.matmult(alg.transpose(inputSet), inputSet)), alg.mat_vec_mult(alg.transpose(inputSet), outputSet));
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}
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bias = stat.mean(outputSet) - alg.dot(weights, x_means);
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forwardPass();
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}
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//} catch (int err_num) {
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// std::cout << "ERR " << err_num << ": Resulting matrix was noninvertible/degenerate, and so the normal equation could not be performed. Try utilizing gradient descent." << std::endl;
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//}
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}
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double LinReg::score() {
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Utilities util;
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return util.performance(y_hat, outputSet);
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}
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void LinReg::save(std::string fileName) {
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Utilities util;
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util.saveParameters(fileName, weights, bias);
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}
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double LinReg::Cost(std::vector<double> y_hat, std::vector<double> y) {
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Reg regularization;
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class MLPPCost cost;
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return cost.MSE(y_hat, y) + regularization.regTerm(weights, lambda, alpha, reg);
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}
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std::vector<double> LinReg::Evaluate(std::vector<std::vector<double>> X) {
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MLPPLinAlg alg;
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return alg.scalarAdd(bias, alg.mat_vec_mult(X, weights));
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}
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double LinReg::Evaluate(std::vector<double> x) {
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MLPPLinAlg alg;
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return alg.dot(weights, x) + bias;
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}
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// wTx + b
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void LinReg::forwardPass() {
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y_hat = Evaluate(inputSet);
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}
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