Yordan Pavlov created ARROW-8598:
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Summary: [Rust] simd_compare_op creates buffer of incorrect length
when item count is not a multiple of T::lanes()
Key: ARROW-8598
URL: https://issues.apache.org/jira/browse/ARROW-8598
Project: Apache Arrow
Issue Type: Bug
Components: Rust
Affects Versions: 0.17.0
Reporter: Yordan Pavlov
the simd_compare_op function defined here
[https://github.com/apache/arrow/blob/master/rust/arrow/src/compute/kernels/comparison.rs#L229]
appears to only work correctly when item count is a multiple of T::lanes().
Otherwise the resulting boolean array is created with a buffer of incorrect
length and subsequent binary operations such as compute::and return an error.
This bug can be reproduced with the following code:
{code:java}
fn main() {
let lanes = Int8Type::lanes();
println("i8 lanes: {}", lanes); // 64
// let item_count = 128; // this works because item_count divides by 64
(lanes) without remainder
let item_count = 130; // this fails because item_count divides by 64
(lanes) with remainder
// item_count = 130 should return error:
// ComputeError("Buffers must be the same size to apply Bitwise AND.")
// create boolean array
let mut select_mask: BooleanArray = vec![true; item_count].into();
// create arrays with i8 values
let value_array: PrimitiveArray<Int8Type> = vec![1; item_count].into();
let filter_array: PrimitiveArray<Int8Type> = vec![2; item_count].into();
// compare i8 arrays and produce a boolean array
let result_mask = compute::gt_eq(&value_array, &filter_array).unwrap();
// compare boolean arrays
select_mask = compute::and(&select_mask, &result_mask).unwrap();
// print result, should be all false
println!("select mask: {:?}", select_mask);
}
{code}
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