{"record":{"id":"a175613ee8fbcd0b","repo":"tensorflow/models","slug":"fusion-type-not-supported-a17561","errorCode":null,"errorMessage":"Fusion type {} not supported.","messagePattern":"Fusion type (.+?) not supported\\.","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"official/vision/modeling/decoders/fpn.py","lineNumber":145,"sourceCode":"    feats = {str(backbone_max_level): feats_lateral[str(backbone_max_level)]}\n    for level in range(backbone_max_level - 1, min_level - 1, -1):\n      feat_a = spatial_transform_ops.nearest_upsampling(\n          feats[str(level + 1)], 2, use_keras_layer=use_keras_layer)\n      feat_b = feats_lateral[str(level)]\n\n      if fusion_type == 'sum':\n        if use_keras_layer:\n          feats[str(level)] = tf_keras.layers.Add()([feat_a, feat_b])\n        else:\n          feats[str(level)] = feat_a + feat_b\n      elif fusion_type == 'concat':\n        if use_keras_layer:\n          feats[str(level)] = tf_keras.layers.Concatenate(axis=-1)(\n              [feat_a, feat_b])\n        else:\n          feats[str(level)] = tf.concat([feat_a, feat_b], axis=-1)\n      else:\n        raise ValueError('Fusion type {} not supported.'.format(fusion_type))\n\n    # TODO(fyangf): experiment with removing bias in conv2d.\n    # Build post-hoc 3x3 convolution kernel.\n    for level in range(min_level, backbone_max_level + 1):\n      feats[str(level)] = conv2d(\n          filters=num_filters,\n          strides=1,\n          kernel_size=3,\n          padding='same',\n          kernel_initializer=kernel_initializer,\n          kernel_regularizer=kernel_regularizer,\n          bias_regularizer=bias_regularizer,\n          name=f'post_hoc_{level}')(\n              feats[str(level)])\n\n    # TODO(fyangf): experiment with removing bias in conv2d.\n    # Build coarser FPN levels introduced for RetinaNet.\n    for level in range(backbone_max_level + 1, max_level + 1):","sourceCodeStart":127,"sourceCodeEnd":163,"githubUrl":"https://github.com/tensorflow/models/blob/e006f5f0d534913e49c1f1dae87364039fa607e2/official/vision/modeling/decoders/fpn.py#L127-L163","documentation":"Error \"Fusion type {} not supported.\" thrown in tensorflow/models.","triggerScenarios":"Thrown at official/vision/modeling/decoders/fpn.py:145 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Use fusion_type 'sum' or 'concat' in the FPN decoder config.","Check the fusion type value for typos."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"e006f5f0d534913e49c1f1dae87364039fa607e2","analyzedAt":"2026-08-24T14:09:15.576Z","schemaVersion":2},"datasetVersion":"2026-08-24T17:17:21.512Z"}