syntax = "proto3";

package tensorflow;
// option cc_enable_arenas = true;

import "tensorflow/core/framework/attr_value.proto";
import "tensorflow/core/framework/function.proto";

// Represents the graph of operations
// TODO(sanjay): Also want to put the following somewhere:
// * random_seed
// * replicas: Do we stamp them out in python itself?
// * where to load parameters
// * optimizer info? does it go with the parameter layers/ops?
message GraphDef {
  repeated NodeDef node = 1;

  // EXPERIMENTAL. DO NOT USE OR DEPEND ON THIS YET.
  //
  // "library" provides user-defined functions.
  //
  // Naming:
  //   * library.function.name are in a flat namespace.
  //     NOTE: We may need to change it to be hierarchical to support
  //     different orgs. E.g.,
  //     { "/google/nn", { ... }},
  //     { "/google/vision", { ... }}
  //     { "/org_foo/module_bar", {...}}
  //     map<string, FunctionDefLib> named_lib;
  //   * If node[i].op is the name of one function in "library",
  //     node[i] is deemed as a function call. Otherwise, node[i].op
  //     must be a primitive operation supported by the runtime.
  //
  //
  // Function call semantics:
  //
  //   * The callee may start execution as soon as some of its inputs
  //     are ready. The caller may want to use Tuple() mechanism to
  //     ensure all inputs are ready in the same time.
  //
  //   * The consumer of return values may start executing as soon as
  //     the return values the consumer depends on are ready.  The
  //     consumer may want to use Tuple() mechanism to ensure the
  //     consumer does not start until all return values of the callee
  //     function are ready.
  FunctionDefLibrary library = 2;
};

message NodeDef {
  // The name given to this operator. Used for naming inputs,
  // logging, visualization, etc.  Unique within a single GraphDef.
  // Must match the regexp "[A-Za-z0-9.][A-Za-z0-9_./]*".
  string name = 1;

  // The operation name.  There may be custom parameters in attrs.
  // Op names starting with an underscore are reserved for internal use.
  string op = 2;

  // Each input is "node:src_output" with "node" being a string name and
  // "src_output" indicating which output tensor to use from "node". If
  // "src_output" is 0 the ":0" suffix can be omitted.  Regular inputs
  // may optionally be followed by control inputs that have the format
  // "^node".
  repeated string input = 3;

  // A (possibly partial) specification for the device on which this
  // node should be placed.
  // The expected syntax for this string is as follows:
  //
  // DEVICE_SPEC ::= COLOCATED_NODE | PARTIAL_SPEC
  //
  // COLOCATED_NODE ::= "@" NODE_NAME  // See NodeDef.name above.
  // PARTIAL_SPEC ::= ("/" CONSTRAINT) *
  // CONSTRAINT ::= ("job:" JOB_NAME)
  //              | ("replica:" [1-9][0-9]*)
  //              | ("task:" [1-9][0-9]*)
  //              | ( ("gpu" | "cpu") ":" ([1-9][0-9]* | "*") )
  //
  // Valid values for this string include:
  // * "@other/node"                         (colocate with "other/node")
  // * "/job:worker/replica:0/task:1/gpu:3"  (full specification)
  // * "/job:worker/gpu:3"                   (partial specification)
  // * ""                                    (no specification)
  //
  // If the constraints do not resolve to a single device (or if this
  // field is empty or not present), the runtime will attempt to
  // choose a device automatically.
  string device = 4;

  // Operation-specific graph-construction-time configuration.
  // Note that this should include all attrs defined in the
  // corresponding OpDef, including those with a value matching
  // the default -- this allows the default to change and makes
  // NodeDefs easier to interpret on their own.  However, if
  // an attr with a default is not specified in this list, the
  // default will be used.
  // The "names" (keys) must match the regexp "[a-z][a-z0-9_]+" (and
  // one of the names from the corresponding OpDef's attr field).
  // The values must have a type matching the corresponding OpDef
  // attr's type field.
  // TODO(josh11b): Add some examples here showing best practices.
  map<string, AttrValue> attr = 5;
};