Fixed NumberNodeStateData bug

Previously, `bound_axes_sums` and `prior_bound_axes_sums`
on `NumberNodeStateData` resulted in segfaults.

Author: fastbodin

dwave/optimization/src/nodes/numbers.cpp

@@ -77,9 +77,9 @@ struct NumberNodeStateData : public ArrayNodeStateData {
     /// bound_axes_sums[i][j] = "sum of the values within the jth slice along
     ///                          the ith bound axis"
     /// Note that "ith bound axis" does not necessarily mean the ith axis.
-    std::vector<std::vector<double>> bound_axes_sums;
+    std::optional<std::vector<std::vector<double>>> bound_axes_sums = std::nullopt;
     // Store a copy for NumberNode::revert() and commit()
-    std::vector<std::vector<double>> prior_bound_axes_sums;
+    std::optional<std::vector<std::vector<double>>> prior_bound_axes_sums = std::nullopt;
 };
 
 double const* NumberNode::buff(const State& state) const noexcept {
@@ -350,7 +350,8 @@ void NumberNode::initialize_state(State& state) const {
 
 void NumberNode::propagate(State& state) const {
     // Should only propagate states that obey the axis-wise bounds.
-    assert(satisfies_axis_wise_bounds(bound_axes_info_, bound_axis_sums(state)));
+    assert(bound_axes_info_.size() == 0 ||
+           satisfies_axis_wise_bounds(bound_axes_info_, bound_axis_sums(state)));
     // Technically vestigial but will keep it for forms sake.
     for (const auto& sv : successors()) {
         sv->update(state, sv.index);
@@ -359,16 +360,22 @@ void NumberNode::propagate(State& state) const {
 
 void NumberNode::commit(State& state) const noexcept {
     auto node_data = data_ptr<NumberNodeStateData>(state);
-    // Manually store a copy of bound_axes_sums.
-    node_data->prior_bound_axes_sums = node_data->bound_axes_sums;
     node_data->commit();
+    if (node_data->prior_bound_axes_sums.has_value()) {
+        assert(node_data->bound_axes_sums.has_value());
+        // Manually store a copy of bound_axes_sums.
+        node_data->prior_bound_axes_sums = node_data->bound_axes_sums;
+    }
 }
 
 void NumberNode::revert(State& state) const noexcept {
     auto node_data = data_ptr<NumberNodeStateData>(state);
-    // Manually reset bound_axes_sums.
-    node_data->bound_axes_sums = node_data->prior_bound_axes_sums;
     node_data->revert();
+    if (node_data->prior_bound_axes_sums.has_value()) {
+        assert(node_data->bound_axes_sums.has_value());
+        // Manually reset bound_axes_sums.
+        node_data->bound_axes_sums = node_data->prior_bound_axes_sums;
+    }
 }
 
 void NumberNode::exchange(State& state, ssize_t i, ssize_t j) const {
@@ -449,7 +456,8 @@ const std::vector<NumberNode::AxisBound>& NumberNode::axis_wise_bounds() const {
 }
 
 const std::vector<std::vector<double>>& NumberNode::bound_axis_sums(const State& state) const {
-    return data_ptr<NumberNodeStateData>(state)->bound_axes_sums;
+    assert(data_ptr<NumberNodeStateData>(state)->bound_axes_sums.has_value());
+    return *data_ptr<NumberNodeStateData>(state)->bound_axes_sums;
 }
 
 template <bool maximum>
@@ -587,7 +595,8 @@ void NumberNode::update_bound_axis_slice_sums(State& state, const ssize_t index,
     const std::vector<ssize_t> multi_index = unravel_index(index, this->shape());
     assert(bound_axes_info.size() <= multi_index.size());
     // Get the slice sums of all bound axes.
-    auto& bound_axes_sums = data_ptr<NumberNodeStateData>(state)->bound_axes_sums;
+    assert(data_ptr<NumberNodeStateData>(state)->bound_axes_sums.has_value());
+    auto& bound_axes_sums = data_ptr<NumberNodeStateData>(state)->bound_axes_sums.value();
     assert(bound_axes_info.size() == bound_axes_sums.size());
 
     // For each bound axis