Finch Logic (High-Level IR)

Finch Logic is an internal high-level intermediate representation (IR) that allows us to fuse and optimize successive calls to array operations such as map, reduce, and broadcast. It is reminiscent to database query notation, representing the a sequence of tensor expressions bound to variables. Values in the program are tensors, with named indices. The order of indices is semantically meaningful.

The nodes are as follows:

Finch.FinchLogic.immediate — Constant

immediate(val)

Logical AST expression for the literal value val.

Finch.FinchLogic.deferred — Constant

deferred(ex, [type])

Logical AST expression for an expression ex of type type, yet to be evaluated.

Finch.FinchLogic.field — Constant

field(name)

Logical AST expression for an field named name.

Finch.FinchLogic.alias — Constant

alias(name)

Logical AST expression for an alias named name.

Finch.FinchLogic.table — Constant

table(tns, idxs...)

Logical AST expression for a tensor object tns, indexed by fields idxs....

Finch.FinchLogic.mapjoin — Constant

mapjoin(op, args...)

Logical AST expression for mapping the function op across args.... The order of fields in the mapjoin is unique(vcat(map(getfields, args)...))

Finch.FinchLogic.aggregate — Constant

aggregate(op, init, arg, idxs...)

Logical AST statement that reduces arg using op, starting with init. idxs are the dimensions to reduce. May happen in any order.

Finch.FinchLogic.reorder — Constant

reorder(arg, idxs...)

Logical AST statement that reorders the dimensions of arg to be idxs.... Dimensions known to be length 1 may be dropped. Dimensions that do not exist in arg may be added.

Finch.FinchLogic.relabel — Constant

relabel(arg, idxs...)

Logical AST statement that relabels the dimensions of arg to be idxs...

Finch.FinchLogic.reformat — Constant

reformat(tns, arg)

Logical AST statement that reformats arg into the tensor tns.

Finch.FinchLogic.subquery — Constant

subquery(lhs, arg)

Logical AST statement that evaluates arg, binding the result to lhs, and returns arg.

Finch.FinchLogic.query — Constant

query(lhs, rhs)

Logical AST statement that evaluates rhs, binding the result to lhs.

Finch.FinchLogic.produces — Constant

produces(args...)

Logical AST statement that returns args... from the current plan. Halts execution of the program.

Finch.FinchLogic.plan — Constant

plan(bodies...)

Logical AST statement that executes a sequence of statements bodies....

Finch Logic Internals

Finch.FinchLogic.LogicNode — Type

LogicNode

A Finch Logic IR node. Finch uses a variant of Concrete Field Notation as an intermediate representation.

The LogicNode struct represents many different Finch IR nodes. The nodes are differentiated by a FinchLogic.LogicNodeKind enum.

Finch.FinchLogic.logic_leaf — Function

logic_leaf(x)

Return a terminal finch node wrapper around x. A convenience function to determine whether x should be understood by default as a immediate or value.

Finch.FinchLogic.isimmediate — Function

isimmediate(node)

Returns true if the node is a finch immediate

Finch.FinchLogic.isdeferred — Function

isdeferred(node)

Returns true if the node is a finch immediate

Finch.FinchLogic.isalias — Function

isalias(node)

Returns true if the node is a finch alias

Finch.FinchLogic.isfield — Function

isfield(node)

Returns true if the node is a finch field

Executing FinchLogic