VariableVector increment_weight_vector(const VariableVector& weights, const VariableVector& scaled_gradient) {
VariableVector empty;
if (weights.size() != scaled_gradient.size()) {
return empty;
}
VariableVector incremented;
string partial_name, weight_name;
double scaled_partial, weight_val;
for (VariableVector::const_iterator it = scaled_gradient.begin(); it != scaled_gradient.end(); ++it) {
partial_name = it->first;
scaled_partial = it->second;
weight_name = partial_name_to_weight_name(partial_name);
if (weights.count(weight_name) == 0) {
return empty;
}
weight_val = weights.at(weight_name);
incremented.insert(make_pair(weight_name, weight_val + scaled_partial));
}
return incremented;
}
VariableVector add_variable_vectors(const VariableVector& vec1, const VariableVector& vec2) {
VariableVector empty;
VariableVector sum;
string var_name;
double component_sum;
// if the vectors are of different sizes, return empty
if (vec1.size() != vec2.size()) return empty;
for (VariableVector::const_iterator it1 = vec1.begin(); it1 != vec1.end(); ++it1) {
var_name = it1->first;
// if this variable is in both vectors, add the values
if (vec2.count(var_name) != 0) {
component_sum = it1->second + vec2.at(var_name);
sum.insert(make_pair(var_name, component_sum));
}
// if this variable is only in vec1, return empty
else {
return empty;
}
}
// if we reach this point, every variable in vec1 is also in vec2
// since both vectors are of the same size, it is safe to return
return sum;
}
VariableVector vector_of_zeros(const vector<string>& var_names) {
VariableVector zeros;
for (vector<string>::const_iterator name = var_names.begin(); name != var_names.end(); ++name) {
zeros.insert(make_pair(*name, 0));
}
return zeros;
}
VariableVector scale_variable_vector(const VariableVector& vec, double scaling_factor) {
VariableVector scaled;
for (VariableVector::const_iterator it = vec.begin(); it != vec.end(); ++it) {
scaled.insert(make_pair(it->first, it->second * scaling_factor));
}
return scaled;
}
const VariableVector variable_vector_union(const VariableVector& vec1, const VariableVector& vec2) {
VariableVector empty;
VariableVector v;
// add all the variables in Vec 1 first
// if any of these variables are seen in Vec 2, this is an error. Return the empty Variable Vector.
// if there is no overlap, then it is safe to add all the variables in Vec 2
for (VariableVector::const_iterator it1 = vec1.begin(); it1 != vec1.end(); ++it1) {
if (vec2.count(it1->first) != 0) {
return empty;
}
v.insert(make_pair(it1->first, it1->second));
}
for (VariableVector::const_iterator it2 = vec2.begin(); it2 != vec2.end(); ++it2) {
v.insert(make_pair(it2->first, it2->second));
}
return v;
}
VariableVector component_wise_div(const VariableVector& vec, double divisor) {
VariableVector quotient;
if (divisor == 0) {
cerr << "Cannot divide by 0." << endl;
return quotient;
}
for (VariableVector::const_iterator it = vec.begin(); it != vec.end(); ++it) {
quotient.insert(make_pair(it->first, it->second / divisor));
}
return quotient;
}