CNN v2: Add debugging tools for mismatch investigation

Add identity weight generator and composited layer save for debugging
HTML/C++ output differences.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 134 insertions, 0 deletions

diff --git a/training/gen_identity_weights.py b/training/gen_identity_weights.py
new file mode 100755
index 0000000..a84ea87
--- /dev/null
+++ b/training/gen_identity_weights.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+"""Generate Identity CNN v2 Weights
+
+Creates trivial .bin with 1 layer, 1×1 kernel, identity passthrough.
+Output Ch{0,1,2,3} = Input Ch{0,1,2,3} (ignores static features).
+
+Usage:
+  ./training/gen_identity_weights.py [output.bin]
+"""
+
+import argparse
+import numpy as np
+import struct
+from pathlib import Path
+
+
+def generate_identity_weights(output_path, kernel_size=1, mip_level=0):
+    """Generate identity weights: output = input (ignores static features).
+
+    Binary format:
+      Header (20 bytes):
+        uint32 magic ('CNN2')
+        uint32 version (2)
+        uint32 num_layers (1)
+        uint32 total_weights (f16 count)
+        uint32 mip_level
+
+      LayerInfo (20 bytes):
+        uint32 kernel_size
+        uint32 in_channels (12)
+        uint32 out_channels (4)
+        uint32 weight_offset (0)
+        uint32 weight_count
+
+      Weights (u32 packed f16):
+        Identity matrix for first 4 input channels
+        Zeros for static features (channels 4-11)
+    """
+    # Identity: 4 output channels, 12 input channels
+    # Weight shape: [out_ch, in_ch, kernel_h, kernel_w]
+    in_channels = 12  # 4 input + 8 static
+    out_channels = 4
+
+    # Identity matrix: diagonal 1.0 for first 4 channels, 0.0 for rest
+    weights = np.zeros((out_channels, in_channels, kernel_size, kernel_size), dtype=np.float32)
+
+    # Center position for kernel
+    center = kernel_size // 2
+
+    # Set diagonal to 1.0 (output ch i = input ch i)
+    for i in range(out_channels):
+        weights[i, i, center, center] = 1.0
+
+    # Flatten
+    weights_flat = weights.flatten()
+    weight_count = len(weights_flat)
+
+    print(f"Generating identity weights:")
+    print(f"  Kernel size: {kernel_size}×{kernel_size}")
+    print(f"  Channels: 12D→4D")
+    print(f"  Weights: {weight_count}")
+    print(f"  Mip level: {mip_level}")
+
+    # Convert to f16
+    weights_f16 = np.array(weights_flat, dtype=np.float16)
+
+    # Pad to even count
+    if len(weights_f16) % 2 == 1:
+        weights_f16 = np.append(weights_f16, np.float16(0.0))
+
+    # Pack f16 pairs into u32
+    weights_u32 = weights_f16.view(np.uint32)
+
+    print(f"  Packed: {len(weights_u32)} u32")
+    print(f"  Binary size: {20 + 20 + len(weights_u32) * 4} bytes")
+
+    # Write binary
+    output_path = Path(output_path)
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+
+    with open(output_path, 'wb') as f:
+        # Header (20 bytes)
+        f.write(struct.pack('<4sIIII',
+                           b'CNN2',           # magic
+                           2,                 # version
+                           1,                 # num_layers
+                           len(weights_f16),  # total_weights
+                           mip_level))        # mip_level
+
+        # Layer info (20 bytes)
+        f.write(struct.pack('<IIIII',
+                           kernel_size,       # kernel_size
+                           in_channels,       # in_channels
+                           out_channels,      # out_channels
+                           0,                 # weight_offset
+                           weight_count))     # weight_count
+
+        # Weights (u32 packed f16)
+        f.write(weights_u32.tobytes())
+
+    print(f"  → {output_path}")
+
+    # Verify
+    print("\nVerification:")
+    with open(output_path, 'rb') as f:
+        data = f.read()
+        magic, version, num_layers, total_weights, mip = struct.unpack('<4sIIII', data[:20])
+        print(f"  Magic: {magic}")
+        print(f"  Version: {version}")
+        print(f"  Layers: {num_layers}")
+        print(f"  Total weights: {total_weights}")
+        print(f"  Mip level: {mip}")
+        print(f"  File size: {len(data)} bytes")
+
+
+def main():
+    parser = argparse.ArgumentParser(description='Generate identity CNN v2 weights')
+    parser.add_argument('output', type=str, nargs='?',
+                       default='workspaces/main/weights/cnn_v2_identity.bin',
+                       help='Output .bin file path')
+    parser.add_argument('--kernel-size', type=int, default=1,
+                       help='Kernel size (default: 1×1)')
+    parser.add_argument('--mip-level', type=int, default=0,
+                       help='Mip level for p0-p3 features (default: 0)')
+
+    args = parser.parse_args()
+
+    print("=== Identity Weight Generator ===\n")
+    generate_identity_weights(args.output, args.kernel_size, args.mip_level)
+    print("\nDone!")
+
+
+if __name__ == '__main__':
+    main()