Detailed Description

Defines the predicated execution model of OpenVX.

These features allow for conditional graph flow in OpenVX, via support for a variety of operations between two scalars. The supported scalar data types VX_TYPE_BOOL, VX_TYPE_INT8, VX_TYPE_UINT8, VX_TYPE_INT16, VX_TYPE_UINT16, VX_TYPE_INT32, VX_TYPE_UINT32, VX_TYPE_SIZE, VX_TYPE_FLOAT32 are supported.
Summary of logical operations:

Scalar Operation	Equation	Data Types
`VX_SCALAR_OP_AND`	output = (a&b)	bool = bool op bool
`VX_SCALAR_OP_OR`	output = (a\|b)	bool = bool op bool
`VX_SCALAR_OP_XOR`	output = (a^b)	bool = bool op bool
`VX_SCALAR_OP_NAND`	output = !(a&b)	bool = bool op bool

Summary of comparison operations:

Scalar Operation	Equation	Data Types
`VX_SCALAR_OP_EQUAL`	output = (a == b)	bool = num op num
`VX_SCALAR_OP_NOTEQUAL`	output = (a != b)	bool = num op num
`VX_SCALAR_OP_LESS`	output = (a < b)	bool = num op num
`VX_SCALAR_OP_LESSEQ`	output = (a <= b)	bool = num op num
`VX_SCALAR_OP_GREATER`	output = (a > b)	bool = num op num
`VX_SCALAR_OP_GREATEREQ`	output = (a >= b)	bool = num op num

Summary of arithmetic operations:

Scalar Operation	Equation	Data Types
`VX_SCALAR_OP_ADD`	output = (a+b)	num = num op num
`VX_SCALAR_OP_SUBTRACT`	output = (a-b)	num = num op num
`VX_SCALAR_OP_MULTIPLY`	output = (a*b)	num = num op num
`VX_SCALAR_OP_DIVIDE`	output = (a/b)	num = num op num
`VX_SCALAR_OP_MODULUS`	output = (ab)	num = num op num
`VX_SCALAR_OP_MIN`	output = min(a,b)	num = num op num
`VX_SCALAR_OP_MAX`	output = max(a,b)	num = num op num

Please note that in the above tables:

bool denotes a scalar of data type VX_TYPE_BOOL
num denotes supported scalar data types are VX_TYPE_INT8, VX_TYPE_UINT8, VX_TYPE_INT16, VX_TYPE_UINT16, VX_TYPE_INT32, VX_TYPE_UINT32, VX_TYPE_SIZE, and VX_TYPE_FLOAT32.
The VX_SCALAR_OP_MODULUS operation supports integer operands.
The results of VX_SCALAR_OP_DIVIDE and VX_SCALAR_OP_MODULUS operations with the second argument as zero, must be defined by the implementation.
For arithmetic and comparison operations with mixed input data types, the results will be mathematically accurate without the side effects of internal data representations.
If the operation result can not be stored in output data type without data and/or precision loss, the following rules shall be applied:
1. If the operation result is integer and output is floating-point, the operation result is promoted to floating-point.
2. If the operation result is floating-point and output is an integer, the operation result is converted to integer with rounding policy VX_ROUND_POLICY_TO_ZERO and conversion policy VX_CONVERT_POLICY_SATURATE.
3. If both operation result and output are integers, the result is converted to output data type with VX_CONVERT_POLICY_WRAP conversion policy.

Functions
vx_node VX_API_CALL	vxScalarOperationNode (vx_graph graph, vx_enum scalar_operation, vx_scalar a, vx_scalar b, vx_scalar output)
	[Graph] Creates a scalar operation node. More...

vx_node VX_API_CALL	vxSelectNode (vx_graph graph, vx_scalar condition, vx_reference true_value, vx_reference false_value, vx_reference output)
	[Graph] Selects one of two data objects depending on the the value of a condition (boolean scalar), and copies its data into another data object. More...

Function Documentation

vx_node VX_API_CALL vxScalarOperationNode	(	vx_graph	graph,
		vx_enum	scalar_operation,
		vx_scalar	a,
		vx_scalar	b,
		vx_scalar	output
	)

[Graph] Creates a scalar operation node.

Parameters

[in]	graph	The reference to the graph.
[in]	scalar_operation	A `VX_TYPE_ENUM` of the `vx_scalar_operation_e` enumeration.
[in]	a	First scalar operand.
[in]	b	Second scalar operand.
[out]	output	Result of the scalar operation.

Returns: vx_node.

Return values

vx_node A node reference. Any possible errors preventing a successful creation should be checked using vxGetStatus

vx_node VX_API_CALL vxSelectNode	(	vx_graph	graph,
		vx_scalar	condition,
		vx_reference	true_value,
		vx_reference	false_value,
		vx_reference	output
	)

[Graph] Selects one of two data objects depending on the the value of a condition (boolean scalar), and copies its data into another data object.

This node supports predicated execution flow within a graph. All the data objects passed to this kernel shall have the same object type and meta data. It is important to note that an implementation may optimize away the select and copy when virtual data objects are used.
If there is a kernel node that contribute only into virtual data objects during the graph execution due to certain data path being eliminated by not taken argument of select node, then the OpenVX implementation guarantees that there will not be any side effects to graph execution and node state.
If the path to a select node contains non-virtual objects, user nodes, or nodes with completion callbacks, then that path may not be "optimized out" because the callback must be executed and the non-virtual objects must be modified.

Parameters

[in]	graph	The reference to the graph.
[in]	condition	`VX_TYPE_BOOL` predicate variable.
[in]	true_value	Data object for true.
[in]	false_value	Data object for false.
[out]	output	Output data object.

Returns: vx_node.

Return values

vx_node A node reference. Any possible errors preventing a successful creation should be checked using vxGetStatus

Detailed Description

Functions

Function Documentation