[GitHub] [arrow-rs] alamb commented on a diff in pull request #4465: Add Datum based arithmetic kernels (#3999)

["alamb (via GitHub)" <gi...@apache.org>]

alamb commented on code in PR #4465:
URL: https://github.com/apache/arrow-rs/pull/4465#discussion_r1247018083


##########
arrow-arith/src/operation.rs:
##########
@@ -0,0 +1,419 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! Arrow arithmetic operations
+
+use crate::arity::{binary, try_binary};
+use arrow_array::cast::AsArray;
+use arrow_array::types::*;
+use arrow_array::*;
+use arrow_schema::{ArrowError, DataType, IntervalUnit, TimeUnit};
+use std::sync::Arc;
+
+/// Perform addition between two `Datum`

Review Comment:
   ```suggestion
   /// Perform addition between two [`Datum`]
   ```



##########
arrow-arith/src/operation.rs:
##########
@@ -0,0 +1,419 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! Arrow arithmetic operations
+
+use crate::arity::{binary, try_binary};
+use arrow_array::cast::AsArray;
+use arrow_array::types::*;
+use arrow_array::*;
+use arrow_schema::{ArrowError, DataType, IntervalUnit, TimeUnit};
+use std::sync::Arc;
+
+/// Perform addition between two `Datum`
+///
+/// An error will be returned if this results in overflow
+pub fn add(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Add, lhs, rhs)
+}
+
+/// Perform addition between two `Datum`
+///
+/// Unlike [`add`] this will not return an error for integer overflow
+pub fn add_wrapping(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::AddWrapping, lhs, rhs)
+}
+
+/// Perform addition between two `Datum`
+///
+/// An error will be returned if this results in overflow
+pub fn sub(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Sub, lhs, rhs)
+}
+
+/// Perform subtraction between two `Datum`
+///
+/// Unlike [`sub`] this will not return an error for integer overflow
+pub fn sub_wrapping(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::SubWrapping, lhs, rhs)
+}
+
+/// Perform multiplication between two `Datum`
+///
+/// An error will be returned if this results in overflow
+pub fn mul(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Mul, lhs, rhs)
+}
+
+/// Perform multiplication between two `Datum`
+///
+/// Unlike [`mul`] this will not return an error for integer overflow
+pub fn mul_wrapping(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::MulWrapping, lhs, rhs)
+}
+
+/// Perform division between two `Datum`
+///
+/// An error will be returned if this results in overflow or would divide by zero
+pub fn div(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Div, lhs, rhs)
+}
+
+/// Compute the remainder of division of two `Datum`
+///
+/// An error will be returned if this results in overflow or would divide by zero
+pub fn rem(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Rem, lhs, rhs)
+}
+
+/// An enumeration of arithmetic operations
+///
+/// This allows sharing the type dispatch logic across the various kernels
+#[derive(Debug, Copy, Clone)]
+enum Op {
+    AddWrapping,
+    Add,
+    SubWrapping,
+    Sub,
+    MulWrapping,
+    Mul,
+    Div,
+    Rem,
+}
+
+/// Dispatch the given `op` to the appropriate specialized kernel
+fn arithmetic_op(
+    op: Op,
+    lhs: &dyn Datum,
+    rhs: &dyn Datum,
+) -> Result<ArrayRef, ArrowError> {
+    use DataType::*;
+    use TimeUnit::*;
+
+    macro_rules! integer_helper {
+        ($t:ty, $op:ident, $l:ident, $l_scalar:ident, $r:ident, $r_scalar:ident) => {
+            integer_op::<$t>($op, $l, $l_scalar, $r, $r_scalar)
+        };
+    }
+
+    let (l, l_scalar) = lhs.get();
+    let (r, r_scalar) = rhs.get();
+    downcast_integer! {
+        l.data_type(), r.data_type() => (integer_helper, op, l, l_scalar, r, r_scalar),
+        (Float16, Float16) => float_op::<Float16Type>(op, l, l_scalar, r, r_scalar),
+        (Float32, Float32) => float_op::<Float32Type>(op, l, l_scalar, r, r_scalar),
+        (Float64, Float64) => float_op::<Float64Type>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Second, _), _) => timestamp_op::<TimestampSecondType>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Millisecond, _), _) => timestamp_op::<TimestampMillisecondType>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Microsecond, _), _) => timestamp_op::<TimestampMicrosecondType>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Nanosecond, _), _) => timestamp_op::<TimestampNanosecondType>(op, l, l_scalar, r, r_scalar),
+        (Date32, _) => date_op::<Date32Type>(op, l, l_scalar, r, r_scalar),
+        (Date64, _) => date_op::<Date64Type>(op, l, l_scalar, r, r_scalar),
+        (l_t, r_t) => Err(ArrowError::InvalidArgumentError(
+            format!("Invalid arithmetic operation: {l_t} {op:?} {r_t}")
+        ))
+    }
+}
+
+/// Perform an infallible binary operation on potentially scalar inputs

Review Comment:
   A nit might be to document that `$l` means the left array and `$l_s` is true f that array should be treated as a scalar (single value)



##########
arrow-arith/src/operation.rs:
##########
@@ -0,0 +1,419 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! Arrow arithmetic operations
+
+use crate::arity::{binary, try_binary};
+use arrow_array::cast::AsArray;
+use arrow_array::types::*;
+use arrow_array::*;
+use arrow_schema::{ArrowError, DataType, IntervalUnit, TimeUnit};
+use std::sync::Arc;
+
+/// Perform addition between two `Datum`
+///
+/// An error will be returned if this results in overflow
+pub fn add(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Add, lhs, rhs)
+}
+
+/// Perform addition between two `Datum`
+///
+/// Unlike [`add`] this will not return an error for integer overflow
+pub fn add_wrapping(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::AddWrapping, lhs, rhs)
+}
+
+/// Perform addition between two `Datum`
+///
+/// An error will be returned if this results in overflow
+pub fn sub(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Sub, lhs, rhs)
+}
+
+/// Perform subtraction between two `Datum`
+///
+/// Unlike [`sub`] this will not return an error for integer overflow
+pub fn sub_wrapping(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::SubWrapping, lhs, rhs)
+}
+
+/// Perform multiplication between two `Datum`
+///
+/// An error will be returned if this results in overflow
+pub fn mul(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Mul, lhs, rhs)
+}
+
+/// Perform multiplication between two `Datum`
+///
+/// Unlike [`mul`] this will not return an error for integer overflow
+pub fn mul_wrapping(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::MulWrapping, lhs, rhs)
+}
+
+/// Perform division between two `Datum`
+///
+/// An error will be returned if this results in overflow or would divide by zero
+pub fn div(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Div, lhs, rhs)
+}
+
+/// Compute the remainder of division of two `Datum`
+///
+/// An error will be returned if this results in overflow or would divide by zero
+pub fn rem(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<ArrayRef, ArrowError> {
+    arithmetic_op(Op::Rem, lhs, rhs)
+}
+
+/// An enumeration of arithmetic operations
+///
+/// This allows sharing the type dispatch logic across the various kernels
+#[derive(Debug, Copy, Clone)]
+enum Op {
+    AddWrapping,
+    Add,
+    SubWrapping,
+    Sub,
+    MulWrapping,
+    Mul,
+    Div,
+    Rem,
+}
+
+/// Dispatch the given `op` to the appropriate specialized kernel
+fn arithmetic_op(
+    op: Op,
+    lhs: &dyn Datum,
+    rhs: &dyn Datum,
+) -> Result<ArrayRef, ArrowError> {
+    use DataType::*;
+    use TimeUnit::*;
+
+    macro_rules! integer_helper {
+        ($t:ty, $op:ident, $l:ident, $l_scalar:ident, $r:ident, $r_scalar:ident) => {
+            integer_op::<$t>($op, $l, $l_scalar, $r, $r_scalar)
+        };
+    }
+
+    let (l, l_scalar) = lhs.get();
+    let (r, r_scalar) = rhs.get();
+    downcast_integer! {
+        l.data_type(), r.data_type() => (integer_helper, op, l, l_scalar, r, r_scalar),
+        (Float16, Float16) => float_op::<Float16Type>(op, l, l_scalar, r, r_scalar),
+        (Float32, Float32) => float_op::<Float32Type>(op, l, l_scalar, r, r_scalar),
+        (Float64, Float64) => float_op::<Float64Type>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Second, _), _) => timestamp_op::<TimestampSecondType>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Millisecond, _), _) => timestamp_op::<TimestampMillisecondType>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Microsecond, _), _) => timestamp_op::<TimestampMicrosecondType>(op, l, l_scalar, r, r_scalar),
+        (Timestamp(Nanosecond, _), _) => timestamp_op::<TimestampNanosecondType>(op, l, l_scalar, r, r_scalar),
+        (Date32, _) => date_op::<Date32Type>(op, l, l_scalar, r, r_scalar),
+        (Date64, _) => date_op::<Date64Type>(op, l, l_scalar, r, r_scalar),
+        (l_t, r_t) => Err(ArrowError::InvalidArgumentError(
+            format!("Invalid arithmetic operation: {l_t} {op:?} {r_t}")
+        ))
+    }
+}
+
+/// Perform an infallible binary operation on potentially scalar inputs
+macro_rules! op {
+    ($l:ident, $l_s:expr, $r:ident, $r_s:expr, $op:expr) => {
+        match ($l_s, $r_s) {
+            (true, true) | (false, false) => binary($l, $r, |$l, $r| $op)?,
+            (true, false) => match ($l.null_count() == 0).then(|| $l.value(0)) {
+                None => PrimitiveArray::new_null($r.len()),
+                Some($l) => $r.unary(|$r| $op),
+            },
+            (false, true) => match ($r.null_count() == 0).then(|| $r.value(0)) {
+                None => PrimitiveArray::new_null($l.len()),
+                Some($r) => $l.unary(|$l| $op),
+            },
+        }
+    };
+}
+
+/// Same as `op` but with a type hint for the returned array
+macro_rules! op_ref {
+    ($t:ty, $l:ident, $l_s:expr, $r:ident, $r_s:expr, $op:expr) => {{
+        let array: PrimitiveArray<$t> = op!($l, $l_s, $r, $r_s, $op);
+        Arc::new(array)
+    }};
+}
+
+/// Perform a fallible binary operation on potentially scalar inputs
+macro_rules! try_op {
+    ($l:ident, $l_s:expr, $r:ident, $r_s:expr, $op:expr) => {
+        match ($l_s, $r_s) {
+            (true, true) | (false, false) => try_binary($l, $r, |$l, $r| $op)?,
+            (true, false) => match ($l.null_count() == 0).then(|| $l.value(0)) {
+                None => PrimitiveArray::new_null($r.len()),
+                Some($l) => $r.try_unary(|$r| $op)?,
+            },
+            (false, true) => match ($r.null_count() == 0).then(|| $r.value(0)) {
+                None => PrimitiveArray::new_null($l.len()),
+                Some($r) => $l.try_unary(|$l| $op)?,
+            },
+        }
+    };
+}
+
+/// Same as `try_op` but with a type hint for the returned array
+macro_rules! try_op_ref {
+    ($t:ty, $l:ident, $l_s:expr, $r:ident, $r_s:expr, $op:expr) => {{
+        let array: PrimitiveArray<$t> = try_op!($l, $l_s, $r, $r_s, $op);
+        Arc::new(array)
+    }};
+}
+
+/// Perform an arithmetic operation on integers
+fn integer_op<T: ArrowPrimitiveType>(
+    op: Op,
+    l: &dyn Array,
+    l_s: bool,
+    r: &dyn Array,
+    r_s: bool,
+) -> Result<ArrayRef, ArrowError> {
+    let l = l.as_primitive::<T>();
+    let r = r.as_primitive::<T>();
+    let array: PrimitiveArray<T> = match op {
+        Op::AddWrapping => op!(l, l_s, r, r_s, l.add_wrapping(r)),
+        Op::Add => try_op!(l, l_s, r, r_s, l.add_checked(r)),
+        Op::SubWrapping => op!(l, l_s, r, r_s, l.sub_wrapping(r)),
+        Op::Sub => try_op!(l, l_s, r, r_s, l.sub_checked(r)),
+        Op::MulWrapping => op!(l, l_s, r, r_s, l.mul_wrapping(r)),
+        Op::Mul => try_op!(l, l_s, r, r_s, l.mul_checked(r)),
+        Op::Div => try_op!(l, l_s, r, r_s, l.div_checked(r)),
+        Op::Rem => try_op!(l, l_s, r, r_s, l.div_checked(r)),
+    };
+    Ok(Arc::new(array))
+}
+
+/// Perform an arithmetic operation on floats
+fn float_op<T: ArrowPrimitiveType>(
+    op: Op,
+    l: &dyn Array,
+    l_s: bool,
+    r: &dyn Array,
+    r_s: bool,
+) -> Result<ArrayRef, ArrowError> {
+    let l = l.as_primitive::<T>();
+    let r = r.as_primitive::<T>();
+    let array: PrimitiveArray<T> = match op {
+        Op::AddWrapping | Op::Add => op!(l, l_s, r, r_s, l.add_wrapping(r)),
+        Op::SubWrapping | Op::Sub => op!(l, l_s, r, r_s, l.sub_wrapping(r)),
+        Op::MulWrapping | Op::Mul => op!(l, l_s, r, r_s, l.mul_wrapping(r)),
+        Op::Div => try_op!(l, l_s, r, r_s, l.div_checked(r)),
+        Op::Rem => try_op!(l, l_s, r, r_s, l.div_checked(r)),
+    };
+    Ok(Arc::new(array))
+}
+
+/// Arithmetic trait for timestamp arrays
+trait TimestampOp: ArrowTimestampType {
+    type Duration: ArrowPrimitiveType<Native = i64>;
+
+    fn add_year_month(timestamp: i64, delta: i32) -> Result<i64, ArrowError>;
+    fn add_day_time(timestamp: i64, delta: i64) -> Result<i64, ArrowError>;
+    fn add_month_day_nano(timestamp: i64, delta: i128) -> Result<i64, ArrowError>;
+
+    fn sub_year_month(timestamp: i64, delta: i32) -> Result<i64, ArrowError>;
+    fn sub_day_time(timestamp: i64, delta: i64) -> Result<i64, ArrowError>;
+    fn sub_month_day_nano(timestamp: i64, delta: i128) -> Result<i64, ArrowError>;
+}
+
+macro_rules! timestamp {
+    ($t:ty, $d:ty) => {
+        impl TimestampOp for $t {
+            type Duration = $d;
+
+            fn add_year_month(left: i64, right: i32) -> Result<i64, ArrowError> {
+                Self::add_year_months(left, right)
+            }
+
+            fn add_day_time(left: i64, right: i64) -> Result<i64, ArrowError> {
+                Self::add_day_time(left, right)
+            }
+
+            fn add_month_day_nano(left: i64, right: i128) -> Result<i64, ArrowError> {
+                Self::add_month_day_nano(left, right)
+            }
+
+            fn sub_year_month(left: i64, right: i32) -> Result<i64, ArrowError> {
+                Self::subtract_year_months(left, right)
+            }
+
+            fn sub_day_time(left: i64, right: i64) -> Result<i64, ArrowError> {
+                Self::subtract_day_time(left, right)
+            }
+
+            fn sub_month_day_nano(left: i64, right: i128) -> Result<i64, ArrowError> {
+                Self::subtract_month_day_nano(left, right)
+            }
+        }
+    };
+}
+timestamp!(TimestampSecondType, DurationSecondType);
+timestamp!(TimestampMillisecondType, DurationMillisecondType);
+timestamp!(TimestampMicrosecondType, DurationMicrosecondType);
+timestamp!(TimestampNanosecondType, DurationNanosecondType);
+
+/// Perform arithmetic operation on a timestamp array
+fn timestamp_op<T: TimestampOp>(
+    op: Op,
+    l: &dyn Array,
+    l_s: bool,
+    r: &dyn Array,
+    r_s: bool,
+) -> Result<ArrayRef, ArrowError> {
+    use DataType::*;
+    use IntervalUnit::*;
+
+    // Note: interval arithmetic should account for timezones (#4457)
+    let l = l.as_primitive::<T>();

Review Comment:
   this is quite beautiful 🤗 



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