utils.cc

#include "utils.h"

using namespace std;
using namespace Eigen;

/* Try splitting over all whitespaces not just space */
vector<string> split_line(const string& line, char delim) {
	vector < string > words;
	stringstream ss(line);
	string item;
	while (std::getline(ss, item, delim)) {
		if (!item.empty())
			words.push_back(item);
	}
	return words;
}

void ReadVecsFromFile(const string& vec_file_name, mapUnsignedStr& vocab,
		vector<Col>& word_vecs) {
	ifstream vec_file(vec_file_name.c_str());
	unsigned vocab_size = 0;
	if (vec_file.is_open()) {
		string line;
		vocab.clear();
		while (getline(vec_file, line)) {
			vector < string > vector_stuff = split_line(line, ' ');
			string word = vector_stuff[0];
			Col word_vec = Col::Zero(vector_stuff.size() - 1);
			for (unsigned i = 0; i < word_vec.size(); ++i)
				word_vec(i, 0) = stof(vector_stuff[i + 1]);
			vocab.push_back(word);
			word_vecs.push_back(word_vec);
		}
		cerr << "Read: " << vec_file_name << endl;
		cerr << "Vocab length: " << word_vecs.size() << endl;
		cerr << "Vector length: " << word_vecs[0].size() << endl << endl;
		vec_file.close();

		assert(word_vecs.size() == vocab.size());
	} else {
		cerr << "Could not open " << vec_file;
		exit(0);
	}
}

void ElemwiseTanh(Col* v) {
for (unsigned i = 0; i < v->rows(); ++i)
	(*v)(i, 0) = tanh((*v)(i, 0));
}

/* v is the vector after taking tanh() */
void ElemwiseTanhGrad(const Col &v, Col* g) {
for (int i = 0; i < v.rows(); ++i)
	(*g)(i, 0) = 1 - pow(v(i, 0), 2);
}

void ElemwiseAndrewNsnl(Col *v) {
for (int i = 0; i < v->rows(); ++i) {
	double x = (*v)(i, 0);
	if (x) {
		bool flag = (x < 0);
		double y_n = flag ? -x : x;
		for (unsigned i = 0; i < 12; ++i) {
			const double sq = y_n * y_n;
			y_n = (2 * sq * y_n / 3 + x) / (sq + 1);
		}
		(*v)(i, 0) = flag ? -y_n : y_n;
	}
}
}

void ElemwiseAndrewNsnlGrad(const Col &v, Col* g) {
for (int i = 0; i < v.rows(); ++i)
	(*g)(i, 0) = 1 / (1 + pow(v(i, 0), 2));
}

double CosineSim(const Col& ci, const Col& cj) {
return ci.dot(cj) / sqrt(ci.squaredNorm() * cj.squaredNorm());
}