ONNX NodeProto and AttributeProto, field by field

Each operation in a graph is a NodeProto: an operator such as Conv or MatMul, the names of the values it reads and writes, and its attributes. The operator’s meaning comes from its operator set, named by domain and given a version in the model’s opset_import.

NodeProto

One node: an operator, its inputs and outputs by name, and its attributes.

Field	Name	Type	Wire type	Meaning
1	`input`	repeated string	LEN, one per name	Input value names, in the operator’s order. An empty name stands for an optional input that is left out.
2	`output`	repeated string	LEN, one per name	Output value names.
3	`name`	string	LEN	The node’s name; optional.
4	`op_type`	string	LEN	The operator, such as `Conv`, or the name of a model-local function. The explorer requires it.
7	`domain`	string	LEN	The operator set’s domain; empty for ONNX’s own operators.
8	`overload`	string	LEN	Which overload of a model-local function (IR 10).
5	`attribute`	repeated AttributeProto	LEN, one per attribute	Named attributes, such as a convolution’s `kernel_shape`.
6	`doc_string`	string	LEN	Documentation.
9	`metadata_props`	repeated StringStringEntryProto	LEN, one per entry	Named metadata (IR 10).
10	`device_configurations`	repeated NodeDeviceConfigurationProto	LEN, one per entry	How the node is spread over devices (IR 11).

AttributeProto

A named attribute of a node: one value of one type, which type names. Exactly one value field is set.

Field	Name	Type	Wire type	Meaning
1	`name`	string	LEN	The attribute’s name.
21	`ref_attr_name`	string	LEN	Inside a function: the name of the caller’s attribute that this one takes its value from.
13	`doc_string`	string	LEN	Documentation.
20	`type`	AttributeType	VARINT	Which value field is used, from the table below (IR 2).
2	`f`	float	I32	A float.
3	`i`	int64	VARINT	An integer.
4	`s`	bytes	LEN	A string, UTF-8.
5	`t`	TensorProto	LEN	A tensor, such as a `Constant` node’s value.
6	`g`	GraphProto	LEN	A graph, such as a branch of `If`.
22	`sparse_tensor`	SparseTensorProto	LEN	A sparse tensor.
14	`tp`	TypeProto	LEN	A type.
7	`floats`	repeated float	I32 per value, or packed LEN	A list of floats.
8	`ints`	repeated int64	VARINT per value, or packed LEN	A list of integers, such as `kernel_shape` or `pads`.
9	`strings`	repeated bytes	LEN, one per string	A list of strings.
10	`tensors`	repeated TensorProto	LEN, one per tensor	A list of tensors.
11	`graphs`	repeated GraphProto	LEN, one per graph	A list of graphs.
23	`sparse_tensors`	repeated SparseTensorProto	LEN, one per tensor	A list of sparse tensors.
15	`type_protos`	repeated TypeProto	LEN, one per type	A list of types.

Fields 12 and 16 to 19 are reserved, and so is the name v.

AttributeType

Value	Name	Field	Value	Name	Field
0	UNDEFINED	–	8	STRINGS	`strings`
1	FLOAT	`f`	9	TENSORS	`tensors`
2	INT	`i`	10	GRAPHS	`graphs`
3	STRING	`s`	11	SPARSE_TENSOR	`sparse_tensor`
4	TENSOR	`t`	12	SPARSE_TENSORS	`sparse_tensors`
5	GRAPH	`g`	13	TYPE_PROTO	`tp`
6	FLOATS	`floats`	14	TYPE_PROTOS	`type_protos`
7	INTS	`ints`

NodeDeviceConfigurationProto

How a node is spread over devices, under one of the model’s device configurations (IR 11).

Field	Name	Type	Wire type	Meaning
1	`configuration_id`	string	LEN	The name of the DeviceConfigurationProto this belongs to.
2	`sharding_spec`	repeated ShardingSpecProto	LEN, one per tensor	How each input or output is sharded.
3	`pipeline_stage`	int32	VARINT	The node’s pipeline stage.

ShardingSpecProto

How one tensor is sharded across devices.

Field	Name	Type	Wire type	Meaning
1	`tensor_name`	string	LEN	The tensor.
2	`device`	repeated int64	VARINT per value, or packed LEN	Devices or device groups.
3	`index_to_device_group_map`	repeated IntIntListEntryProto	LEN, one per entry	The devices in each device group.
4	`sharded_dim`	repeated ShardedDimProto	LEN, one per axis	The sharding of each axis.

ShardedDimProto

The sharding of one axis of a tensor.

Field	Name	Type	Wire type	Meaning
1	`axis`	int64	VARINT	The axis.
2	`simple_sharding`	repeated SimpleShardedDimProto	LEN, one per step	How it is divided.

SimpleShardedDimProto

A dimension of N blocks divided into M shards.

Field	Name	Type	Wire type	Meaning
1	`dim_value`	int64	VARINT	The dimension as a number (oneof `dim`).
2	`dim_param`	string	LEN	The dimension as a name (oneof `dim`).
3	`num_shards`	int64	VARINT	How many shards.

IntIntListEntryProto

A key and a list of integers.

Field	Name	Type	Wire type	Meaning
1	`key`	int64	VARINT	The key.
2	`value`	repeated int64	VARINT per value, or packed LEN	The values.

.ONNX File Format – NodeProto and attributes