Struct Approx 

pub struct Approx;

Approximate conversion

This rounding mode allows an implementation-defined rounding mode. The result must be close to the input value (see below).

Example: 2.1_f32 may convert to 2_i32 or to 3_i32 (either implementation is valid so long as the behaviour is well-defined).

Limits of approximation

(This section applies to all Rounding modes provided by easy-cast except for Exact.)

The output value of a successful conversion must be close to the input value. More precisely, the distance between the input and output values should be less than the distance between the two closest representable values in the target type. For example, 1.9_f32 may be approximated to 1_i32 or 2_i32 since mathematically 1.9 lies between 1 and 2. As another example, 1_f64 + (f32::EPSILON as f64) / 2.0 may be approximated to 1_f32 or 1_f32 + f32::EPSILON.

Infinity “values” like f32::INFINITY are a bit special; essentially we allow any input of the appropriate sign to approximate to “infinity” where the input may not approximate to another value. For example, the above rules may be used to calculate the maximum u128 value which is allowed to approximate to f32::MAX (0xFFFFFF7F_FFFFFFFF_FFFFFFFF_FFFFFFFF); the value above this should thus approximate to f32::INFINITY.

Trait Implementations

impl Clone for Approx

fn clone(&self) -> Approx

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S, T: ConvExact<S>> ConvTo<S, Approx> for T

type Error = <T as ConvExact<S>>::Error

Conversion error type

fn try_conv_to(_: Approx, s: S) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, s: S) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for i8

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for i16

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for i32

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for i64

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for i128

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for isize

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for u8

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for u16

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for u32

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for u64

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for usize

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f32, Approx> for u128

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f32) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f32) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for f32

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<f32, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> f32

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for i8

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for i16

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for i32

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for i64

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for i128

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for isize

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for u8

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for u16

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for u32

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for u64

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for u128

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<f64, Approx> for usize

type Error = RangeError

Conversion error type

fn try_conv_to(_: Approx, x: f64) -> Result<Self, Self::Error>

Try converting from S to Self, rounding according to mode

fn conv_to(_: Approx, x: f64) -> Self

Convert from S to Self, rounding according to mode

impl ConvTo<i32, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: i32) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: i32) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<i64, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: i64) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: i64) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<i64, Approx> for f64

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: i64) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: i64) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<i128, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: i128) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: i128) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<i128, Approx> for f64

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: i128) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: i128) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<isize, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: isize) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: isize) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<isize, Approx> for f64

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: isize) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: isize) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<u32, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: u32) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: u32) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<u64, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: u64) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: u64) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<u64, Approx> for f64

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: u64) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: u64) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<u128, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: u128) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: u128) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<u128, Approx> for f64

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: u128) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: u128) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<usize, Approx> for f32

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: usize) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: usize) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl ConvTo<usize, Approx> for f64

type Error = Infallible

Conversion error type

fn conv_to(_: Approx, x: usize) -> Self

Convert from S to Self, rounding according to mode

fn try_conv_to(_: Approx, x: usize) -> Result<Self, Infallible>

Try converting from S to Self, rounding according to mode

impl Copy for Approx

impl Debug for Approx

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Approx

fn default() -> Approx

Returns the “default value” for a type.

impl Rounding for Approx

type MaximumError = RangeError

Maximum error type