nevi-me commented on a change in pull request #9313: URL: https://github.com/apache/arrow/pull/9313#discussion_r571213170
########## File path: rust/arrow/src/compute/kernels/trigonometry.rs ########## @@ -0,0 +1,246 @@ +// 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. + +//! Defines trigonometry kernels for `PrimitiveArrays` that are +//! floats, restricted by the [num::Float] trait. + +use std::{iter::FromIterator, ops::Div}; + +use num::{Float, Zero}; + +use super::math::*; +use crate::buffer::Buffer; +use crate::datatypes::ArrowNumericType; +use crate::error::Result; +use crate::{ + array::*, + compute::{add, math_op, multiply, subtract}, + datatypes::ArrowPrimitiveType, + error::ArrowError, + float_unary, +}; + +use super::arity::{into_primitive_array_data, unary}; + +float_unary!(to_degrees); +float_unary!(to_radians); +float_unary!(sin); +float_unary!(cos); +float_unary!(tan); +float_unary!(asin); +float_unary!(acos); +float_unary!(atan); +float_unary!(sinh); +float_unary!(cosh); +float_unary!(tanh); +float_unary!(asinh); +float_unary!(acosh); +float_unary!(atanh); + +pub fn atan2<T>( + left: &PrimitiveArray<T>, + right: &PrimitiveArray<T>, +) -> Result<PrimitiveArray<T>> +where + T: ArrowNumericType, + T::Native: num::traits::Float, +{ + math_op(left, right, |x, y| x.atan2(y)) +} + +/// Perform `left * right` operation on two arrays. If either left or right value is null +/// then the result is also null. +pub fn sin_cos<T>(array: &PrimitiveArray<T>) -> (PrimitiveArray<T>, PrimitiveArray<T>) +where + T: ArrowNumericType, + T::Native: num::traits::Float, +{ + let (sin, cos): (Vec<T::Native>, Vec<T::Native>) = + array.values().iter().map(|v| v.sin_cos()).unzip(); + // NOTE: due to `unzip` collecting and splitting the arrays, + // this might be slower than Buffer::from_trusted_len_iter + let sin_buffer = Buffer::from_iter(sin); + let cos_buffer = Buffer::from_iter(cos); + + let sin_data = into_primitive_array_data::<_, T>(array, sin_buffer); + let cos_data = into_primitive_array_data::<_, T>(array, cos_buffer); + ( + PrimitiveArray::<T>::from(std::sync::Arc::new(sin_data)), + PrimitiveArray::<T>::from(std::sync::Arc::new(cos_data)), + ) +} + +/// Calculate the Haversine distance between two geographic coordinates. +/// Based on the haversine crate. +/// +/// The distance returned is in meters, and the radius must be specified in meters. +pub fn haversine<T>( + lat_a: &PrimitiveArray<T>, + lng_a: &PrimitiveArray<T>, + lat_b: &PrimitiveArray<T>, + lng_b: &PrimitiveArray<T>, + radius: impl num::traits::Float, +) -> Result<PrimitiveArray<T>> +where + T: ArrowPrimitiveType + ArrowNumericType, + T::Native: num::traits::Float + Div<Output = T::Native> + Zero + num::NumCast, +{ + // Check array lengths, must all equal + let len = lat_a.len(); + if lat_b.len() != len || lng_a.len() != len || lng_b.len() != len { + return Err(ArrowError::ComputeError( + "Cannot perform math operation on arrays of different length".to_string(), + )); + } + // These casts normally get optimized to f64 as f64 + let one = num::cast::<_, T::Native>(1.0).unwrap(); + let two = num::cast::<_, T::Native>(2.0).unwrap(); + let radius = num::cast::<_, T::Native>(radius).unwrap(); + let two_radius = two * radius; + + let lat_delta = to_radians(&subtract(lat_b, lat_a)?); + let lng_delta = to_radians(&subtract(lng_b, lng_a)?); + let lat_a_rad = to_radians(lat_a); + let lat_b_rad = to_radians(lat_b); + + let v1: PrimitiveArray<T> = sin(&unary::<_, _, _>(&lat_delta, |x| x / two)); + let v2: PrimitiveArray<T> = sin(&unary::<_, _, _>(&lng_delta, |x| x / two)); + + let a = add( + // powf is slower than x * x + &unary::<_, _, _>(&v1, |x: T::Native| x * x), + // This could be simplified if we had a ternary kernel that takes 3 args + // F(T::Native, T::Native, T::Native) -> T::Native + &multiply( + // powf is slower than x * x + &unary::<_, _, _>(&v2, |x: T::Native| x * x), + &math_op(&lat_a_rad, &lat_b_rad, |x, y| (x.cos() * y.cos()))?, + )?, + )?; + Ok(unary::<_, _, _>( + &atan2(&sqrt(&a), &sqrt(&unary::<_, _, _>(&a, |x| one - x)))?, + |x| x * two_radius, + )) +} + +// only added here to test that it's accurate +pub fn haversine_no_unary<T>( Review comment: I've removed it, as it's also in the benchmark ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
