use num_traits::pow::Pow;
use num_traits::{Float, One, ToPrimitive, Zero};
use polars_core::error::{PolarsResult, polars_bail, polars_ensure, polars_err};
use polars_core::prelude::arity::{broadcast_binary_elementwise, unary_elementwise_values};
use polars_core::prelude::{
ChunkApply, ChunkedArray, Column, DataType, IntoColumn, PolarsFloatType, PolarsIntegerType,
PolarsNumericType,
};
use polars_core::with_match_physical_integer_type;
fn pow_on_chunked_arrays<T, F>(
base: &ChunkedArray<T>,
exponent: &ChunkedArray<F>,
) -> ChunkedArray<T>
where
T: PolarsNumericType,
F: PolarsNumericType,
T::Native: Pow<F::Native, Output = T::Native> + ToPrimitive,
{
if exponent.len() == 1 {
if let Some(e) = exponent.get(0) {
if e == F::Native::zero() {
return unary_elementwise_values(base, |_| T::Native::one());
}
if e == F::Native::one() {
return base.clone();
}
if e == F::Native::one() + F::Native::one() {
return base * base;
}
}
}
broadcast_binary_elementwise(base, exponent, |b, e| Some(Pow::pow(b?, e?)))
}
fn pow_on_floats<T>(base: &ChunkedArray<T>, exponent: &ChunkedArray<T>) -> PolarsResult<Column>
where
T: PolarsFloatType,
T::Native: Pow<T::Native, Output = T::Native> + ToPrimitive + Float,
ChunkedArray<T>: IntoColumn,
{
let dtype = T::get_static_dtype();
if exponent.len() == 1 {
let Some(exponent_value) = exponent.get(0) else {
return Ok(Column::full_null(base.name().clone(), base.len(), &dtype));
};
let s = match exponent_value.to_f64().unwrap() {
1.0 => base.clone().into_column(),
0.5 => base.apply_values(|v| v.sqrt()).into_column(),
a if a.fract() == 0.0 && a < 10.0 && a > 1.0 => {
let mut out = base.clone();
for _ in 1..exponent_value.to_u8().unwrap() {
out = out * base.clone()
}
out.into_column()
},
_ => base
.apply_values(|v| Pow::pow(v, exponent_value))
.into_column(),
};
Ok(s)
} else {
Ok(pow_on_chunked_arrays(base, exponent).into_column())
}
}
fn pow_to_uint_dtype<T, F>(
base: &ChunkedArray<T>,
exponent: &ChunkedArray<F>,
) -> PolarsResult<Column>
where
T: PolarsIntegerType,
F: PolarsIntegerType,
T::Native: Pow<F::Native, Output = T::Native> + ToPrimitive,
ChunkedArray<T>: IntoColumn,
{
let dtype = T::get_static_dtype();
if exponent.len() == 1 {
let Some(exponent_value) = exponent.get(0) else {
return Ok(Column::full_null(base.name().clone(), base.len(), &dtype));
};
let s = match exponent_value.to_u64().unwrap() {
1 => base.clone().into_column(),
2..=10 => {
let mut out = base.clone();
for _ in 1..exponent_value.to_u8().unwrap() {
out = out * base.clone()
}
out.into_column()
},
_ => base
.apply_values(|v| Pow::pow(v, exponent_value))
.into_column(),
};
Ok(s)
} else {
Ok(pow_on_chunked_arrays(base, exponent).into_column())
}
}
fn pow_on_series(base: &Column, exponent: &Column) -> PolarsResult<Column> {
let base_dtype = base.dtype();
polars_ensure!(
base_dtype.is_primitive_numeric(),
InvalidOperation: "`pow` operation not supported for dtype `{}` as base", base_dtype
);
let exponent_dtype = exponent.dtype();
polars_ensure!(
exponent_dtype.is_primitive_numeric(),
InvalidOperation: "`pow` operation not supported for dtype `{}` as exponent", exponent_dtype
);
if base_dtype.is_integer() {
with_match_physical_integer_type!(base_dtype, |$native_type| {
if exponent_dtype.is_float() {
match exponent_dtype {
#[cfg(feature = "dtype-f16")]
Float16 => {
let ca = base.cast(&DataType::Float16)?;
let exponent = exponent.strict_cast(&DataType::Float16)?;
pow_on_floats(ca.f16().unwrap(), exponent.f16().unwrap())
},
Float32 => {
let ca = base.cast(&DataType::Float32)?;
pow_on_floats(ca.f32().unwrap(), exponent.f32().unwrap())
},
Float64 => {
let ca = base.cast(&DataType::Float64)?;
pow_on_floats(ca.f64().unwrap(), exponent.f64().unwrap())
},
_ => unreachable!(),
}
} else {
let ca = base.$native_type().unwrap();
let exponent = exponent.strict_cast(&DataType::UInt32).map_err(|err| polars_err!(
InvalidOperation:
"{}\n\nHint: if you were trying to raise an integer to a negative integer power, please cast your base or exponent to float first.",
err
))?;
pow_to_uint_dtype(ca, exponent.u32().unwrap())
}
})
} else {
match base_dtype {
#[cfg(feature = "dtype-f16")]
DataType::Float16 => {
let ca = base.f16().unwrap();
let exponent = exponent.strict_cast(&DataType::Float16)?;
pow_on_floats(ca, exponent.f16().unwrap())
},
DataType::Float32 => {
let ca = base.f32().unwrap();
let exponent = exponent.strict_cast(&DataType::Float32)?;
pow_on_floats(ca, exponent.f32().unwrap())
},
DataType::Float64 => {
let ca = base.f64().unwrap();
let exponent = exponent.strict_cast(&DataType::Float64)?;
pow_on_floats(ca, exponent.f64().unwrap())
},
_ => unreachable!(),
}
}
}
pub(super) fn pow(s: &mut [Column]) -> PolarsResult<Column> {
let base = &s[0];
let exponent = &s[1];
let base_len = base.len();
let exp_len = exponent.len();
match (base_len, exp_len) {
(1, _) | (_, 1) => pow_on_series(base, exponent),
(len_a, len_b) if len_a == len_b => pow_on_series(base, exponent),
_ => polars_bail!(
ComputeError:
"exponent shape: {} in `pow` expression does not match that of the base: {}",
exp_len, base_len,
),
}
}
pub(super) fn sqrt(base: &Column) -> PolarsResult<Column> {
match base.dtype() {
#[cfg(feature = "dtype-f16")]
DataType::Float16 => {
let ca = base.f16().unwrap();
sqrt_on_floats(ca)
},
DataType::Float32 => {
let ca = base.f32().unwrap();
sqrt_on_floats(ca)
},
DataType::Float64 => {
let ca = base.f64().unwrap();
sqrt_on_floats(ca)
},
_ => {
let base = base.cast(&DataType::Float64)?;
sqrt(&base)
},
}
}
fn sqrt_on_floats<T>(base: &ChunkedArray<T>) -> PolarsResult<Column>
where
T: PolarsFloatType,
T::Native: Pow<T::Native, Output = T::Native> + ToPrimitive + Float,
ChunkedArray<T>: IntoColumn,
{
Ok(base.apply_values(|v| v.sqrt()).into_column())
}
pub(super) fn cbrt(base: &Column) -> PolarsResult<Column> {
match base.dtype() {
#[cfg(feature = "dtype-f16")]
DataType::Float16 => {
let ca = base.f16().unwrap();
cbrt_on_floats(ca)
},
DataType::Float32 => {
let ca = base.f32().unwrap();
cbrt_on_floats(ca)
},
DataType::Float64 => {
let ca = base.f64().unwrap();
cbrt_on_floats(ca)
},
_ => {
let base = base.cast(&DataType::Float64)?;
cbrt(&base)
},
}
}
fn cbrt_on_floats<T>(base: &ChunkedArray<T>) -> PolarsResult<Column>
where
T: PolarsFloatType,
T::Native: Pow<T::Native, Output = T::Native> + ToPrimitive + Float,
ChunkedArray<T>: IntoColumn,
{
Ok(base.apply_values(|v| v.cbrt()).into_column())
}