[jira] [Created] (ARROW-9975) min and max aggregate kernels are inconsistent for floating point types.

["Ritchie (Jira)" <ji...@apache.org>]

Ritchie created ARROW-9975:
------------------------------

             Summary: min and max aggregate kernels are inconsistent for floating point types. 
                 Key: ARROW-9975
                 URL: https://issues.apache.org/jira/browse/ARROW-9975
             Project: Apache Arrow
          Issue Type: Bug
          Components: Rust
    Affects Versions: 1.0.1
            Reporter: Ritchie


The aggregation kernels min and max yield inconsistent results if there are NaN values in the arrays.

Related issue: https://github.com/ritchie46/polars/issues/71

{code:c++}
        use arrow::{
            datatypes::Float32Type,
            compute::kernels::aggregate::min,
            array::{
                PrimitiveBuilder
            }
        };
        let mut builder_1 = PrimitiveBuilder::<Float64Type>::new(2);
        builder_1.append_value(1.0).unwrap();
        builder_1.append_value(f64::NAN).unwrap();
        let array_1 = builder_1.finish();

        let mut builder_2 = PrimitiveBuilder::<Float64Type>::new(2);
        builder_2.append_value(f64::NAN).unwrap();
        builder_2.append_value(1.0).unwrap();
        let array_2 = builder_2.finish();
 
        // expect both nan, or both 1.0
        assert_eq!(min(&array_1), min(&array_2));
{code}

Outputs:

{code:bash}
Left:  Some(1.0)
Right: Some(NaN)
<Click to see difference>

thread 'frame::ser::csv::test::test_' panicked at 'assertion failed: `(left == right)`
  left: `Some(1.0)`,
 right: `Some(NaN)`', polars/src/frame/ser/csv.rs:328:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/73dc675b9437c2a51a975a9f58cc66f05463c351/library/std/src/panicking.rs:483
   1: std::panicking::begin_panic_fmt
             at /rustc/73dc675b9437c2a51a975a9f58cc66f05463c351/library/std/src/panicking.rs:437
   2: polars::frame::ser::csv::test::test_
             at ./src/frame/ser/csv.rs:328
   3: polars::frame::ser::csv::test::test_::{{closure}}
             at ./src/frame/ser/csv.rs:310
   4: core::ops::function::FnOnce::call_once
             at /home/ritchie46/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:227
   5: core::ops::function::FnOnce::call_once
             at /rustc/73dc675b9437c2a51a975a9f58cc66f05463c351/library/core/src/ops/function.rs:227
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: test failed, to rerun pass '-p polars --lib'
{code}





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