Declaration of ProcessRounding graph processor.
ProcessRounding graph processor, to analyze rounding and support regular operations on it.
__init__(rounding_exactness: Exactness)apply(graph: Graph)process_predecessors(graph: Graph, node: Node)Process predecessors of the rounding.
process_successors(graph: Graph, node: Node)Process successors of the rounding.
replace_with_tlu(graph: Graph, node: Node)Replace rounding node with a TLU node that simulates rounding.
This is a special case where:
- user wanted to remove 1-bits
- there was an overflow
- overflow protection was on
Let's say user wanted to remove 1-bit from 3-bits, but there was an overflow:
- [0, 1, 2, 3, 4, 5, 6, 7] would be mapped to [0, 2, 2, 4, 4, 6, 6, 8]
- or in the actual implementation [(0)00, (0)01, (0)01, (0)10, (0)10, (0)11, (0)11, (1)00]
- (first bit is the padding bit, which is overwritten on overflows)
- so the input is 3-bits and the output needs to be 3-bits to store the result
- which can't be achieved with rounding
- so we just replace the rounding with a TLU
- using the table [0, 2, 2, 4, 4, 6, 6, 8]