[major] fix runtime error when controlnet is not present

src/FluxModel.cpp

@@ -736,8 +736,6 @@ Tensor FluxModel::forward(
     const int img_tokens = hidden_states.shape[1];
 
     const int numLayers = transformer_blocks.size() + single_transformer_blocks.size();
-    const int num_controlnet_block_samples = controlnet_block_samples.shape[0];
-    const int num_controlnet_single_block_samples = controlnet_single_block_samples.shape[0];
 
     Tensor concat;
 
@@ -747,6 +745,8 @@ Tensor FluxModel::forward(
             auto &block = transformer_blocks.at(layer);
             std::tie(hidden_states, encoder_hidden_states) = block->forward(hidden_states, encoder_hidden_states, temb, rotary_emb_img, rotary_emb_context, 0.0f);
             if (controlnet_block_samples.valid()) {
+                const int num_controlnet_block_samples = controlnet_block_samples.shape[0];
+
                 int interval_control = ceilDiv(transformer_blocks.size(), static_cast<size_t>(num_controlnet_block_samples));
                 int block_index = layer / interval_control;
                 // Xlabs ControlNet
@@ -770,6 +770,8 @@ Tensor FluxModel::forward(
             auto &block = single_transformer_blocks.at(layer - transformer_blocks.size());
             hidden_states = block->forward(hidden_states, temb, rotary_emb_single);
             if (controlnet_single_block_samples.valid()) {
+                const int num_controlnet_single_block_samples = controlnet_single_block_samples.shape[0];
+
                 int interval_control = ceilDiv(single_transformer_blocks.size(), static_cast<size_t>(num_controlnet_single_block_samples));
                 int block_index = (layer - transformer_blocks.size()) / interval_control;
                 // Xlabs ControlNet
@@ -826,10 +828,9 @@ std::tuple<Tensor, Tensor> FluxModel::forward_layer(
     const int txt_tokens = encoder_hidden_states.shape[1];
     const int img_tokens = hidden_states.shape[1];
 
-    const int num_controlnet_block_samples = controlnet_block_samples.shape[0];
-    const int num_controlnet_single_block_samples = controlnet_single_block_samples.shape[0];
-
     if (layer < transformer_blocks.size() && controlnet_block_samples.valid()) {
+        const int num_controlnet_block_samples = controlnet_block_samples.shape[0];
+
         int interval_control = ceilDiv(transformer_blocks.size(), static_cast<size_t>(num_controlnet_block_samples));
         int block_index = layer / interval_control;
         // Xlabs ControlNet
@@ -837,6 +838,8 @@ std::tuple<Tensor, Tensor> FluxModel::forward_layer(
 
         hidden_states = kernels::add(hidden_states, controlnet_block_samples[block_index]);
     } else if (layer >= transformer_blocks.size() && controlnet_single_block_samples.valid()) {
+        const int num_controlnet_single_block_samples = controlnet_single_block_samples.shape[0];
+
         int interval_control = ceilDiv(single_transformer_blocks.size(), static_cast<size_t>(num_controlnet_single_block_samples));
         int block_index = (layer - transformer_blocks.size()) / interval_control;
         // Xlabs ControlNet