Structure

# Double

A double-precision, floating-point value type.

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## Topics

### Converting Integers

`init<Source>(Source)`

Creates a new value, rounded to the closest possible representation.

`init(Int)`

Creates a new value, rounded to the closest possible representation.

### Converting Strings

`init?<S>(S)`

Creates a new instance from the given string.

### Converting Floating-Point Values

`init<Source>(Source)`

Creates a new instance from the given value, rounded to the closest possible representation.

`init(Double)`

Creates a new instance initialized to the given value.

`init(Float)`

Creates a new instance that approximates the given value.

`init(Float80)`

Creates a new instance that approximates the given value.

`init(CGFloat)`

Creates a new instance initialized to the given value.

`init(sign: FloatingPointSign, exponent: Int, significand: Double)`

Creates a new value from the given sign, exponent, and significand.

`init(signOf: Double, magnitudeOf: Double)`

Creates a new floating-point value using the sign of one value and the magnitude of another.

`init<Source>(Source)`

Creates a new value, rounded to the closest possible representation.

### Converting with No Loss of Precision

These initializers result in `nil` if the value passed can't be represented without any loss of precision.

`init?<Source>(exactly: Source)`

Creates a new instance from the given value, if it can be represented exactly.

`init?<Source>(exactly: Source)`

Creates a new value, if the given integer can be represented exactly.

`init?(exactly: Double)`

Creates a new instance initialized to the given value, if it can be represented without rounding.

`init?(exactly: Float)`

Creates a new instance initialized to the given value, if it can be represented without rounding.

`init?(exactly: Float80)`

Creates a new instance initialized to the given value, if it can be represented without rounding.

### Creating a Random Value

`static func random(in: Range<Double>) -> Double`

Returns a random value within the specified range.

`static func random<T>(in: Range<Double>, using: inout T) -> Double`

Returns a random value within the specified range, using the given generator as a source for randomness.

`static func random(in: ClosedRange<Double>) -> Double`

Returns a random value within the specified range.

`static func random<T>(in: ClosedRange<Double>, using: inout T) -> Double`

Returns a random value within the specified range, using the given generator as a source for randomness.

### Performing Calculations

Floating-Point Operators for Double

Perform arithmetic and bitwise operations or compare values.

`func addingProduct(Double, Double) -> Double`

Returns the result of adding the product of the two given values to this value, computed without intermediate rounding.

`func addProduct(Double, Double)`

Adds the product of the two given values to this value in place, computed without intermediate rounding.

`func squareRoot() -> Double`

Returns the square root of the value, rounded to a representable value.

`func formSquareRoot()`

Replaces this value with its square root, rounded to a representable value.

`func remainder(dividingBy: Double) -> Double`

Returns the remainder of this value divided by the given value.

`func formRemainder(dividingBy: Double)`

Replaces this value with the remainder of itself divided by the given value.

`func truncatingRemainder(dividingBy: Double) -> Double`

Returns the remainder of this value divided by the given value using truncating division.

`func formTruncatingRemainder(dividingBy: Double)`

Replaces this value with the remainder of itself divided by the given value using truncating division.

`func negate()`

Replaces this value with its additive inverse.

### Rounding Values

`func rounded() -> Double`

Returns this value rounded to an integral value using “schoolbook rounding.”

`func rounded(FloatingPointRoundingRule) -> Double`

Returns this value rounded to an integral value using the specified rounding rule.

`func round()`

Rounds this value to an integral value using “schoolbook rounding.”

`func round(FloatingPointRoundingRule)`

Rounds the value to an integral value using the specified rounding rule.

### Comparing Values

Floating-Point Operators for Double

Perform arithmetic and bitwise operations or compare values.

`func isEqual(to: Double) -> Bool`

Returns a Boolean value indicating whether this instance is equal to the given value.

`func isLess(than: Double) -> Bool`

Returns a Boolean value indicating whether this instance is less than the given value.

`func isLessThanOrEqualTo(Double) -> Bool`

Returns a Boolean value indicating whether this instance is less than or equal to the given value.

`func isTotallyOrdered(belowOrEqualTo: Double) -> Bool`

Returns a Boolean value indicating whether this instance should precede or tie positions with the given value in an ascending sort.

`static func minimum(Double, Double) -> Double`

Returns the lesser of the two given values.

`static func maximum(Double, Double) -> Double`

Returns the greater of the two given values.

### Finding the Sign and Magnitude

`var magnitude: Double`

The magnitude of this value.

`var sign: FloatingPointSign`

The sign of the floating-point value.

`typealias Double.Magnitude`

A type that can represent the absolute value of any possible value of this type.

### Querying a Double

`var ulp: Double`

The unit in the last place of this value.

`var significand: Double`

The significand of the floating-point value.

`var exponent: Int`

The exponent of the floating-point value.

`var nextUp: Double`

The least representable value that compares greater than this value.

`var nextDown: Double`

The greatest representable value that compares less than this value.

`var binade: Double`

The floating-point value with the same sign and exponent as this value, but with a significand of 1.0.

### Accessing Numeric Constants

`static var pi: Double`

The mathematical constant pi.

`static var greatestFiniteMagnitude: Double`

The greatest finite number representable by this type.

`static var nan: Double`

A quiet NaN (“not a number”).

`static var signalingNaN: Double`

A signaling NaN (“not a number”).

`static var ulpOfOne: Double`

The unit in the last place of 1.0.

### Working with Binary Representation

`var bitPattern: UInt64`

The bit pattern of the value’s encoding.

`var significandBitPattern: UInt64`

The raw encoding of the value’s significand field.

`var significandWidth: Int`

The number of bits required to represent the value’s significand.

`var exponentBitPattern: UInt`

The raw encoding of the value’s exponent field.

`static var significandBitCount: Int`

The available number of fractional significand bits.

`static var exponentBitCount: Int`

The number of bits used to represent the type’s exponent.

`static var radix: Int`

The radix, or base of exponentiation, for this floating-point type.

`init(bitPattern: UInt64)`

Creates a new value with the given bit pattern.

`init(nan: Double.RawSignificand, signaling: Bool)`

Creates a NaN (“not a number”) value with the specified payload.

`typealias Double.Exponent`

A type that can represent any written exponent.

`typealias Double.RawSignificand`

A type that represents the encoded significand of a value.

### Querying a Double's State

`var isZero: Bool`

A Boolean value indicating whether the instance is equal to zero.

`var isFinite: Bool`

A Boolean value indicating whether this instance is finite.

`var isInfinite: Bool`

A Boolean value indicating whether the instance is infinite.

`var isNaN: Bool`

A Boolean value indicating whether the instance is NaN (“not a number”).

`var isSignalingNaN: Bool`

A Boolean value indicating whether the instance is a signaling NaN.

`var isNormal: Bool`

A Boolean value indicating whether this instance is normal.

`var isSubnormal: Bool`

A Boolean value indicating whether the instance is subnormal.

`var isCanonical: Bool`

A Boolean value indicating whether the instance’s representation is in the canonical form.

### Encoding and Decoding Values

`func encode(to: Encoder)`

Encodes this value into the given encoder.

`init(from: Decoder)`

Creates a new instance by decoding from the given decoder.

### Creating a Range

`static func ..< (Double, Double) -> Range<Double>`

Returns a half-open range that contains its lower bound but not its upper bound.

`static func ... (Double, Double) -> ClosedRange<Double>`

Returns a closed range that contains both of its bounds.

### Describing a Double

`var description: String`

A textual representation of the value.

`var debugDescription: String`

A textual representation of the value, suitable for debugging.

`var customMirror: Mirror`

A mirror that reflects the `Double` instance.

`func hash(into: inout Hasher)`

Hashes the essential components of this value by feeding them into the given hasher.

### Infrequently Used Functionality

`init()`

Creates a value initialized to zero.

`init(floatLiteral: Double)`

Creates a new value from the given floating-point literal.

`init(integerLiteral: Int64)`

Creates a new value from the given integer literal.

`init(integerLiteral: Double)`

Creates an instance initialized to the specified integer value.

`func advanced(by: Double) -> Double`

Returns a new value advanced by the given distance.

`func distance(to: Double) -> Double`

Returns the distance from this value to the specified value.

`func write<Target>(to: inout Target)`

Writes a textual representation of this instance into the given output stream.

### SIMD-Supporting Types

`struct Double.SIMD2Storage`

Storage for a vector of two floating-point values.

`struct Double.SIMD4Storage`

Storage for a vector of four floating-point values.

`struct Double.SIMD8Storage`

Storage for a vector of eight floating-point values.

`struct Double.SIMD16Storage`

Storage for a vector of 16 floating-point values.

`struct Double.SIMD32Storage`

Storage for a vector of 32 floating-point values.

`struct Double.SIMD64Storage`

Storage for a vector of 64 floating-point values.

### Deprecated

`var customPlaygroundQuickLook: _PlaygroundQuickLook`

A custom playground Quick Look for the `Double` instance.

Deprecated

### Type Aliases

`typealias Double.FloatLiteralType`

A type that represents a floating-point literal.

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`typealias Double.IntegerLiteralType`

A type that represents an integer literal.

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`typealias Double.RawExponent`

A type that represents the encoded exponent of a value.

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`typealias Double.Stride`

A type that represents the distance between two values.

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### Standard Library

`struct Int`

A signed integer value type.

`struct String`

A Unicode string value that is a collection of characters.

`struct Array`

An ordered, random-access collection.

`struct Dictionary`

A collection whose elements are key-value pairs.

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This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.