poplar::program::Switch Class Reference

A program that runs one of many programs depending on the value of a tensor. More...

#include <Program.hpp>

Inheritance diagram for poplar::program::Switch:

Public Member Functions
	Switch (Tensor control, const std::vector< std::pair< std::int32_t, Program > > &cases, const DebugContext &debugContext={})
	Construct a switch with the specified set of cases and an empty default case. More...
	Switch (Tensor control, const std::vector< std::pair< std::int32_t, Program > > &cases, const Program &defaultCaseBody, const DebugContext &debugContext={})
	Construct a switch with the specified set of cases and default case. More...
	Switch (Tensor control, const DebugContext &debugContext={})
	Construct a switch with no cases and an empty default case. More...
	Switch (Tensor control, const Program &defaultCaseBody, const DebugContext &debugContext={})
	Construct a switch with no cases and the specified default case. More...
Switch &	add (std::int32_t value, const Program &body)
	Add a case with the specified case value and body. More...

Static Public Member Functions
static Switch	switchWithBoundsChecking (Tensor control, const std::vector< std::pair< std::int32_t, Program > > &cases, const DebugContext &debugContext={})
	A helper function that causes the default case to throw an error.
static Switch	switchWithUnreachableDefault (Tensor control, const DebugContext &debugContext={})
	This function lets the compiler assume the default case is unreachable. More...

Detailed Description

A program that runs one of many programs depending on the value of a tensor.

The controlling tensor must be a scalar of type INT or UNSIGNED_INT.

A switch contains of a number of switch cases, each with a case value and a case body and a default case. The case values must be unique. If the value of the controlling tensor matches the case value of a case the corresponding case body is run, otherwise the default case is run.

Constructor & Destructor Documentation

Switch() [1/4]

poplar::program::Switch::Switch	(	Tensor	control,
		const std::vector< std::pair< std::int32_t, Program > > &	cases,
		const DebugContext &	debugContext = {}
	)

Construct a switch with the specified set of cases and an empty default case.

Parameters

control	The controlling tensor.
cases	The cases of the switch: value and program to run.
debugContext	Optional DebugId and program name.

Switch() [2/4]

poplar::program::Switch::Switch	(	Tensor	control,
		const std::vector< std::pair< std::int32_t, Program > > &	cases,
		const Program &	defaultCaseBody,
		const DebugContext &	debugContext = {}
	)

Construct a switch with the specified set of cases and default case.

Parameters

control	The controlling tensor.
cases	The cases of the switch: value and program to run.
defaultCaseBody	The body of the default case.
debugContext	Optional DebugId and program name.

Switch() [3/4]

poplar::program::Switch::Switch	(	Tensor	control,
		const DebugContext &	debugContext = {}
	)

Construct a switch with no cases and an empty default case.

The add() method can be used to add cases after the switch is constructed.

Parameters

control	The controlling tensor.
debugContext	Optional DebugId and program name.

Switch() [4/4]

poplar::program::Switch::Switch	(	Tensor	control,
		const Program &	defaultCaseBody,
		const DebugContext &	debugContext = {}
	)

Construct a switch with no cases and the specified default case.

The add() method can be used to add cases after the switch is constructed.

Parameters

control	The controlling tensor.
defaultCaseBody	The body of the default case.
debugContext	Optional DebugId and program name.

Member Function Documentation

add()

Switch & poplar::program::Switch::add	(	std::int32_t	value,
		const Program &	body
	)

Add a case with the specified case value and body.

Parameters

value	The case value.
body	The case body.

Returns

A reference to the switch program.

switchWithUnreachableDefault()

static Switch poplar::program::Switch::switchWithUnreachableDefault ( Tensor  control, const DebugContext &  debugContext = {}  )

static

This function lets the compiler assume the default case is unreachable.

If the control value is something other than one of the cases, it results in undefined behaviour (although there is some very minimal error checking at runtime).

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The documentation for this class was generated from the following file:

• include/poplar/Program.hpp