add documentation for client

paddle/go/pserver/client.go

@@ -13,49 +13,71 @@ const (
 	Float64
 )
 
+// Parameter is a piece of data to sync with the parameter server.
 type Parameter struct {
 	Name        string
 	ElementType ElementType
 	Content     []byte
 }
 
+// ParameterWithConfig contains the parameter and the configuration.
 type ParameterWithConfig struct {
 	Param  Parameter
-	Config []byte
+	Config []byte // parameter configuration in Proto Buffer format
 }
 
+// Gradient is the gradient of the parameter.
 type Gradient Parameter
 
+// Client is the client to parameter servers.
 type Client struct {
 }
 
+// NewClient creates a new client.
 func NewClient(addr string) *Client {
 	return &Client{}
 }
 
-func (c *Client) BeginInitParams(pserverConfigProto []byte) (bool, error) {
+// BeginInitParams begins to initialize parameters on parameter
+// servers.
+//
+// BeginInitParams will be called from multiple trainers, only one
+// trainer will be selected to initialize the parameters on parameter
+// servers. Other trainers will be blocked until the initialization is
+// done, and they need to get the initialized parameters from
+// parameter servers using GetParams.
+func (c *Client) BeginInitParams(pserverConfigProto []byte) (selected bool, err error) {
 	return true, nil
 }
 
+// InitParam initializes the parameter on parameter servers.
 func (c *Client) InitParam(paramWithConfigs ParameterWithConfig) error {
 	return nil
 }
 
+// FinishInitParams tells parameter servers client has sent all
+// parameters to parameter servers as initialization.
 func (c *Client) FinishInitParams() error {
 	return nil
 }
 
+// SendGrads sends gradients to parameter servers for updating
+// parameters.
 func (c *Client) SendGrads(grads []Gradient) error {
 	return nil
 }
 
+// GetParams gets parameters from parameter servers.
 func (c *Client) GetParams(names []string) ([]Parameter, error) {
 	return nil, nil
 }
 
+// SaveModel indicates parameters to save the parameter to the given
+// path.
 func (c *Client) SaveModel(path string) error {
 	return nil
 }
 
+// Cleanup cleans up the client states.
 func (c *Client) Cleanup() {
 }