Trait CheckedLogBasePowerOf2

pub trait CheckedLogBasePowerOf2<POW> {
    type Output;

    // Required method
    fn checked_log_base_power_of_2(self, pow: POW) -> Option<Self::Output>;
}

Calculates the base-$2^k$ logarithm of a number, or returns None if the number is not a perfect power of $2^k$.

Required Associated Types

type Output

Required Methods

fn checked_log_base_power_of_2(self, pow: POW) -> Option<Self::Output>

Implementations on Foreign Types

impl CheckedLogBasePowerOf2<u64> for f32

fn checked_log_base_power_of_2(self, pow: u64) -> Option<i64>

Returns the base-$2^k$ logarithm of a positive float. If the float is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self or pow are 0.

Examples

See here.

type Output = i64

impl CheckedLogBasePowerOf2<u64> for f64

fn checked_log_base_power_of_2(self, pow: u64) -> Option<i64>

Returns the base-$2^k$ logarithm of a positive float. If the float is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self or pow are 0.

Examples

See here.

type Output = i64

impl CheckedLogBasePowerOf2<u64> for u8

fn checked_log_base_power_of_2(self, pow: u64) -> Option<u64>

Returns the base-$2^k$ logarithm of a positive integer. If the integer is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self is infinite, NaN, or less than or equal to zero, or if pow is zero.

Examples

See here.

type Output = u64

impl CheckedLogBasePowerOf2<u64> for u16

fn checked_log_base_power_of_2(self, pow: u64) -> Option<u64>

Returns the base-$2^k$ logarithm of a positive integer. If the integer is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self is infinite, NaN, or less than or equal to zero, or if pow is zero.

Examples

See here.

type Output = u64

impl CheckedLogBasePowerOf2<u64> for u32

fn checked_log_base_power_of_2(self, pow: u64) -> Option<u64>

Returns the base-$2^k$ logarithm of a positive integer. If the integer is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self is infinite, NaN, or less than or equal to zero, or if pow is zero.

Examples

See here.

type Output = u64

impl CheckedLogBasePowerOf2<u64> for u64

fn checked_log_base_power_of_2(self, pow: u64) -> Option<u64>

Returns the base-$2^k$ logarithm of a positive integer. If the integer is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self is infinite, NaN, or less than or equal to zero, or if pow is zero.

Examples

See here.

type Output = u64

impl CheckedLogBasePowerOf2<u64> for u128

fn checked_log_base_power_of_2(self, pow: u64) -> Option<u64>

Returns the base-$2^k$ logarithm of a positive integer. If the integer is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self is infinite, NaN, or less than or equal to zero, or if pow is zero.

Examples

See here.

type Output = u64

impl CheckedLogBasePowerOf2<u64> for usize

fn checked_log_base_power_of_2(self, pow: u64) -> Option<u64>

Returns the base-$2^k$ logarithm of a positive integer. If the integer is not a power of $2^k$, None is returned.

$$ f(x, k) = \begin{cases} \operatorname{Some}(\log_{2^k} x) & \text{if} \quad \log_{2^k} x \in \Z, \\ \operatorname{None} & \textrm{otherwise}. \end{cases} $$

Worst-case complexity

Constant time and additional memory.

Panics

Panics if self is infinite, NaN, or less than or equal to zero, or if pow is zero.

Examples

See here.

type Output = u64

Implementors