NDS Namespace Reference

The NDS client namespace. More...

Classes
struct	availability
	Availability information for a channel. More...
class	availability_list_type
	A list of availabilitys (channels, availability segments) More...
class	buffer
	A buffer holds the data contents of a channel. More...
class	channel
	Represents a LIGO data channel. More...
struct	channel_data_type_conversion
	Given a C++ data type, determine which NDS channel data type applies to it. More...
class	channel_predicate_object
	A predicate object to be used in limiting the number of channels returned when searching for channels. More...
class	connection
	A connection to the NDS/NDS2 server. More...
class	data_iterable
	The data_iterable manages streaming data from an NDS::connection. More...
class	data_stream_iterator
	A input iterator. More...
struct	frequency_range
	A simple range for sample rates. More...
class	parameters
	The parameters class holds the configuration for a connection. This includes gap handling strategy and server connection information. More...
struct	request_period
	This represents a [start, stop) time with an optional data stride. More...
struct	segment
	An availability segment defines when data is available. More...
class	segment_list_type
	A list of detailed segments. This does not contain the channel name. More...
class	simple_availability_list_type
	A list of simple availability lists. More...
struct	simple_segment
	A simple [start,stop) range for denoting segments. More...
class	simple_segment_list_type
	A list of simple segments. This does not contain the channel name. More...

Functions
template<typename... Args>
channel_predicate_object	channel_predicate (Args... args)
NDS::buffers_type	fetch (const NDS::parameters &params, buffer::gps_second_type gps_start, buffer::gps_second_type gps_stop, const NDS::connection::channel_names_type &channel_names)
	Retreive data from the server without having to manage a connection.
NDS::buffers_type	fetch (buffer::gps_second_type gps_start, buffer::gps_second_type gps_stop, const NDS::connection::channel_names_type &channel_names)
	Retreive data from the server without having to manage a connection.
NDS::data_iterable	iterate (const NDS::parameters &params, NDS::request_period period, const NDS::connection::channel_names_type &channel_names)
	Retreive data in segments without having to manage a connection.
NDS::data_iterable	iterate (NDS::request_period period, const NDS::connection::channel_names_type &channel_names)
	Retreive data in segments without having to manage a connection.
channels_type	find_channels (const NDS::parameters &params, const channel_predicate_object &pred)
	Retrieve a list of channels without having to manage a connection.
channels_type	find_channels (const channel_predicate_object &pred)
	Retrieve a list of channels without having to manage a connection.
DLL_EXPORT NDS::buffers_type	fetch (const NDS::parameters &params, buffer::gps_second_type gps_start, buffer::gps_second_type gps_stop, const NDS::connection::channel_names_type &channel_names)
	Retreive data from the server without having to manage a connection.
DLL_EXPORT NDS::buffers_type	fetch (buffer::gps_second_type gps_start, buffer::gps_second_type gps_stop, const NDS::connection::channel_names_type &channel_names)
	Retreive data from the server without having to manage a connection.
DLL_EXPORT NDS::data_iterable	iterate (const NDS::parameters &params, NDS::request_period period, const NDS::connection::channel_names_type &channel_names)
	Retreive data in segments without having to manage a connection.
DLL_EXPORT NDS::data_iterable	iterate (NDS::request_period period, const NDS::connection::channel_names_type &channel_names)
	Retreive data in segments without having to manage a connection.
DLL_EXPORT channels_type	find_channels (const NDS::parameters &params, const channel_predicate_object &pred)
	Retrieve a list of channels without having to manage a connection.
DLL_EXPORT channels_type	find_channels (const channel_predicate_object &pred)
	Retrieve a list of channels without having to manage a connection.

Detailed Description

The NDS client namespace.

Function Documentation

channel_predicate()

template<typename... Args>

channel_predicate_object NDS::abi_0::channel_predicate

(

Args...

args

)

Create a ChannelPredicate object initialized with the parameters to this call.

Template Parameters

Args	The types of args

Parameters

args	arguments predicate object.

Returns

A ChannelPredicate object which has been initialized with the search parameters specified.

Note

Each argument passed to this function is used to set a constraint in a ChannelPredicate object.

fetch() [1/4]

NDS::buffers_type NDS::abi_0::fetch	(	buffer::gps_second_type	gps_start,
		buffer::gps_second_type	gps_stop,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data from the server without having to manage a connection.

Given a start/stop time and a channel list retrieve the associated data, pulling connection information from the environment.

Parameters

[in]	gps_start	Start time of request
[in]	gps_stop	Stop time of request
[in]	channel_names	The channel list

Returns

A list of buffers containing the request data.

Remarks

The server to connect to, gap handlers, ... are all configured via the environment.

fetch() [2/4]

DLL_EXPORT NDS::buffers_type NDS::abi_0::fetch	(	buffer::gps_second_type	gps_start,
		buffer::gps_second_type	gps_stop,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data from the server without having to manage a connection.

Given a start/stop time and a channel list retrieve the associated data, pulling connection information from the environment.

Parameters

[in]	gps_start	Start time of request
[in]	gps_stop	Stop time of request
[in]	channel_names	The channel list

Returns

A list of buffers containing the request data.

Remarks

The server to connect to, gap handlers, ... are all configured via the environment.

fetch() [3/4]

NDS::buffers_type NDS::abi_0::fetch	(	const NDS::parameters &	params,
		buffer::gps_second_type	gps_start,
		buffer::gps_second_type	gps_stop,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data from the server without having to manage a connection.

Given a start/stop time and a channel list retrieve the associated data.

Parameters

[in]	params	Parameters object specifying connection settings
[in]	gps_start	Start time of request
[in]	gps_stop	Stop time of request
[in]	channel_names	The channel list

Returns

A list of buffers containing the request data.

Remarks

The params argument should be used to specify how fetch selects gap handlers, deals with data on tape, and provide a specific server to connect to.

fetch() [4/4]

DLL_EXPORT NDS::buffers_type NDS::abi_0::fetch	(	const NDS::parameters &	params,
		buffer::gps_second_type	gps_start,
		buffer::gps_second_type	gps_stop,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data from the server without having to manage a connection.

Given a start/stop time and a channel list retrieve the associated data.

Parameters

[in]	params	Parameters object specifying connection settings
[in]	gps_start	Start time of request
[in]	gps_stop	Stop time of request
[in]	channel_names	The channel list

Returns

A list of buffers containing the request data.

Remarks

The params argument should be used to specify how fetch selects gap handlers, deals with data on tape, and provide a specific server to connect to.

find_channels() [1/4]

channels_type NDS::abi_0::find_channels

(

const channel_predicate_object &

pred

)

Retrieve a list of channels without having to manage a connection.

Return a list of channels that are available form this connection within the given contstraints.

Parameters

[in]

pred

A channel_predicate object holding the constraints to impose on the search.

Returns

A count of channels matching the input parameters.

Remarks

This may result in multiple requests being sent to the server.

Note

The server(s) that are queried for channel lists is pulled from the environment. To specify a specific server use the overload that takes a parameters object.

// Return all channels
auto chans = find_channels(channel_predicate());

// Return all DMT channels
auto chans = conn.find_channels(channel_predicate("*DMT*"));

// Return all 16Hz-2KHz channels that are 32 bit integers
auto chans =
find_channels(channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32);

// Return all 16Hz-2KHz channels that are 32 bit integers
// from the O1 run.
auto chans =
find_channels(channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32, epoch("O1"));

find_channels() [2/4]

DLL_EXPORT channels_type NDS::abi_0::find_channels

(

const channel_predicate_object &

pred

)

Retrieve a list of channels without having to manage a connection.

Return a list of channels that are available form this connection within the given contstraints.

Parameters

[in]

pred

A channel_predicate object holding the constraints to impose on the search.

Returns

A count of channels matching the input parameters.

Remarks

This may result in multiple requests being sent to the server.

Note

The server(s) that are queried for channel lists is pulled from the environment. To specify a specific server use the overload that takes a parameters object.

// Return all channels
auto chans = find_channels(channel_predicate());

// Return all DMT channels
auto chans = conn.find_channels(channel_predicate("*DMT*"));

// Return all 16Hz-2KHz channels that are 32 bit integers
auto chans =
find_channels(channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32);

// Return all 16Hz-2KHz channels that are 32 bit integers
// from the O1 run.
auto chans =
find_channels(channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32, epoch("O1"));

find_channels() [3/4]

channels_type NDS::abi_0::find_channels	(	const NDS::parameters &	params,
		const channel_predicate_object &	pred
	)

Retrieve a list of channels without having to manage a connection.

Return a list of channels that are available form this connection within the given contstraints.

Parameters

[in]	params	A parameters object used to specify a specific server
[in]	pred	A channel_predicate object holding the constraints to impose on the search.

Returns

A count of channels matching the input parameters.

Remarks

This may result in multiple requests being sent to the server.

// Return all channels
auto params = parameters(hostname, port);
auto chans = find_channels(params, channel_predicate());

// Return all DMT channels
auto params = parameters(hostname, port);
auto chans = conn.find_channels(params, channel_predicate("*DMT*"));

// Return all 16Hz-2KHz channels that are 32 bit integers
auto params = parameters(hostname, port);
auto chans =
find_channels(params, channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32);

// Return all 16Hz-2KHz channels that are 32 bit integers
// from the O1 run.
auto params = parameters(hostname, port);
auto chans =
find_channels(params, channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32, epoch("O1"));

find_channels() [4/4]

DLL_EXPORT channels_type NDS::abi_0::find_channels	(	const NDS::parameters &	params,
		const channel_predicate_object &	pred
	)

Retrieve a list of channels without having to manage a connection.

Return a list of channels that are available form this connection within the given contstraints.

Parameters

[in]	params	A parameters object used to specify a specific server
[in]	pred	A channel_predicate object holding the constraints to impose on the search.

Returns

A count of channels matching the input parameters.

Remarks

This may result in multiple requests being sent to the server.

// Return all channels
auto params = parameters(hostname, port);
auto chans = find_channels(params, channel_predicate());

// Return all DMT channels
auto params = parameters(hostname, port);
auto chans = conn.find_channels(params, channel_predicate("*DMT*"));

// Return all 16Hz-2KHz channels that are 32 bit integers
auto params = parameters(hostname, port);
auto chans =
find_channels(params, channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32);

// Return all 16Hz-2KHz channels that are 32 bit integers
// from the O1 run.
auto params = parameters(hostname, port);
auto chans =
find_channels(params, channel_predicate(FrequencyRange(16.0, 2000.),
channel::data_type::DATA_TYPE_INT32, epoch("O1"));

iterate() [1/4]

NDS::data_iterable NDS::abi_0::iterate	(	const NDS::parameters &	params,
		NDS::request_period	period,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data in segments without having to manage a connection.

Setup an iterative data retrieval process. This function initiates the request for data in range specified by period, but does not actually retreive the data. Instead it returns a data_stream object which manages the data iteration request.

Parameters

[in]	params	Parameters object specifying connection settings
[in]	period	The range of data to return. It may be any range that a request_period may express, including unbounded live data, bounded live data, or bounded historical data.
[in]	channel_names	The list of channels to retrieve data for.

Returns

A data_iterable object which manages the iteration.

Note

All iterate calls must be terminated. If you break out of an iterate loop without retrieving all of the available data you must call the abort() method of the data_iterable object to ensure that a network connection is not left open to the server. This will eventually happen when all references to the data_iterable object and the iterators it refers to are destructed.

// to stream live data from a connection object 'conn'.
auto params = parameters(hostname, port);
auto stream = iterate(params, NDS::request_period(),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}

// To stream historical data, skipping over gaps
// it is assumed that start, stop are defined elsewhere
// but are in scope.
auto params = parameters();
params.set("ITERATE_USE_GAP_HANDLERS", "false");
auto stream = iterate(params, NDS::request_period(start, stop),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}

iterate() [2/4]

DLL_EXPORT NDS::data_iterable NDS::abi_0::iterate	(	const NDS::parameters &	params,
		NDS::request_period	period,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data in segments without having to manage a connection.

Setup an iterative data retrieval process. This function initiates the request for data in range specified by period, but does not actually retreive the data. Instead it returns a data_stream object which manages the data iteration request.

Parameters

[in]	params	Parameters object specifying connection settings
[in]	period	The range of data to return. It may be any range that a request_period may express, including unbounded live data, bounded live data, or bounded historical data.
[in]	channel_names	The list of channels to retrieve data for.

Returns

A data_iterable object which manages the iteration.

Note

All iterate calls must be terminated. If you break out of an iterate loop without retrieving all of the available data you must call the abort() method of the data_iterable object to ensure that a network connection is not left open to the server. This will eventually happen when all references to the data_iterable object and the iterators it refers to are destructed.

// to stream live data from a connection object 'conn'.
auto params = parameters(hostname, port);
auto stream = iterate(params, NDS::request_period(),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}

// To stream historical data, skipping over gaps
// it is assumed that start, stop are defined elsewhere
// but are in scope.
auto params = parameters();
params.set("ITERATE_USE_GAP_HANDLERS", "false");
auto stream = iterate(params, NDS::request_period(start, stop),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}

iterate() [3/4]

NDS::data_iterable NDS::abi_0::iterate	(	NDS::request_period	period,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data in segments without having to manage a connection.

Setup an iterative data retrieval process. This function initiates the request for data in range specified by period, but does not actually retreive the data. Instead it returns a data_stream object which manages the data iteration request.

Parameters

[in]	period	The range of data to return. It may be any range that a request_period may express, including unbounded live data, bounded live data, or bounded historical data.
[in]	channel_names	The list of channels to retrieve data for.

Returns

A data_iterable object which manages the iteration.

Note

All iterate calls must be terminated. If you break out of an iterate loop without retrieving all of the available data you must call the abort() method of the data_iterable object to ensure that a network connection is not left open to the server. This will eventually happen when all references to the data_iterable object and the iterators it refers to are destructed.

// to stream live data from a connection object 'conn'.
auto stream = iterate(NDS::request_period(),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}

// To stream historical data.
// it is assumed that start, stop are defined elsewhere
// but are in scope.
// Note if to explicitly set gap handlers/... use the
// overload which accepts a parameters object.
auto stream = iterate(NDS::request_period(start, stop),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}

iterate() [4/4]

DLL_EXPORT NDS::data_iterable NDS::abi_0::iterate	(	NDS::request_period	period,
		const NDS::connection::channel_names_type &	channel_names
	)

Retreive data in segments without having to manage a connection.

Setup an iterative data retrieval process. This function initiates the request for data in range specified by period, but does not actually retreive the data. Instead it returns a data_stream object which manages the data iteration request.

Parameters

[in]	period	The range of data to return. It may be any range that a request_period may express, including unbounded live data, bounded live data, or bounded historical data.
[in]	channel_names	The list of channels to retrieve data for.

Returns

A data_iterable object which manages the iteration.

Note

All iterate calls must be terminated. If you break out of an iterate loop without retrieving all of the available data you must call the abort() method of the data_iterable object to ensure that a network connection is not left open to the server. This will eventually happen when all references to the data_iterable object and the iterators it refers to are destructed.

// to stream live data from a connection object 'conn'.
auto stream = iterate(NDS::request_period(),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}

// To stream historical data.
// it is assumed that start, stop are defined elsewhere
// but are in scope.
// Note if to explicitly set gap handlers/... use the
// overload which accepts a parameters object.
auto stream = iterate(NDS::request_period(start, stop),
{"H1:GDS-CALIB_STRAIN,online",});
for (auto it:stream) {
     // *it will be a std::shared_ptr<NDS::buffers_type>
     std::cout << (*it)->Start();
}