Add boolean equality and inequality kernels

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

I am trying to compare two boolean arrays (see DataFusion PR apache/datafusion#1163) and produce another BooleanArray

There are a variety of kernels in arrow that support comparing primitive (numeric) arrays and string arrays such as eq, eq_utf8 eq_scalar, etc.

https://docs.rs/arrow/6.0.0/arrow/compute/kernels/comparison/index.html

Describe the solution you'd like

I would like the following four kernels in arrow (see implementations in apache/datafusion#1163)

// return a new BooleanArray which is the result of comparing left and right element by element
fn eq_bool(left: &BooleanArray, right: &BooleanArray) -> result<BooleanArray> {
  ..
}
// return a new BooleanArray which is the result of comparing left and right element by element
fn neq_bool(left: &BooleanArray, right: &BooleanArray) -> result<BooleanArray> {
  ..
}
// return a new BooleanArray which is the result of comparing left and right element by element
fn eq_bool_scalar(left: &BooleanArray, right: bool) -> result<BooleanArray> {
  ..
}
// return a new BooleanArray which is the result of comparing left and right element by element
fn neq_bool_scalar(left: &BooleanArray, right: bool) -> result<BooleanArray> {
  ..
}

[Dandandan]

Seems to me we can/should implement this with bitwise operations, i.e. !(x ^ y)

[Dandandan]

Let me have a go at this

[alamb]

Seems to me we can/should implement this with bitwise operations, i.e. !(x ^ y)

I assume you mean calculate more than one element of each array at a time (like do it 8 or 64 bits at a time):

[Dandandan]

Seems to me we can/should implement this with bitwise operations, i.e. !(x ^ y)

I assume you mean calculate more than one element of each array at a time (like do it 8 or 64 bits at a time):

Yes, that was the idea (u64 at a time). See the PR for the implementation :)