const.go

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package math provides basic constants and mathematical functions.
     6  //
     7  // This package does not guarantee bit-identical results across architectures.
     8  package math
     9  
    10  // Mathematical constants.
    11  const (
    12  	E   = 2.71828182845904523536028747135266249775724709369995957496696763 // https://oeis.org/A001113
    13  	Pi  = 3.14159265358979323846264338327950288419716939937510582097494459 // https://oeis.org/A000796
    14  	Phi = 1.61803398874989484820458683436563811772030917980576286213544862 // https://oeis.org/A001622
    15  
    16  	Sqrt2   = 1.41421356237309504880168872420969807856967187537694807317667974 // https://oeis.org/A002193
    17  	SqrtE   = 1.64872127070012814684865078781416357165377610071014801157507931 // https://oeis.org/A019774
    18  	SqrtPi  = 1.77245385090551602729816748334114518279754945612238712821380779 // https://oeis.org/A002161
    19  	SqrtPhi = 1.27201964951406896425242246173749149171560804184009624861664038 // https://oeis.org/A139339
    20  
    21  	Ln2    = 0.693147180559945309417232121458176568075500134360255254120680009 // https://oeis.org/A002162
    22  	Log2E  = 1 / Ln2
    23  	Ln10   = 2.30258509299404568401799145468436420760110148862877297603332790 // https://oeis.org/A002392
    24  	Log10E = 1 / Ln10
    25  )
    26  
    27  // Floating-point limit values.
    28  // Max is the largest finite value representable by the type.
    29  // SmallestNonzero is the smallest positive, non-zero value representable by the type.
    30  const (
    31  	MaxFloat32             = 0x1p127 * (1 + (1 - 0x1p-23)) // 3.40282346638528859811704183484516925440e+38
    32  	SmallestNonzeroFloat32 = 0x1p-126 * 0x1p-23            // 1.401298464324817070923729583289916131280e-45
    33  
    34  	MaxFloat64             = 0x1p1023 * (1 + (1 - 0x1p-52)) // 1.79769313486231570814527423731704356798070e+308
    35  	SmallestNonzeroFloat64 = 0x1p-1022 * 0x1p-52            // 4.9406564584124654417656879286822137236505980e-324
    36  )
    37  
    38  // Integer limit values.
    39  const (
    40  	intSize = 32 << (^uint(0) >> 63) // 32 or 64
    41  
    42  	MaxInt    = 1<<(intSize-1) - 1
    43  	MinInt    = -1 << (intSize - 1)
    44  	MaxInt8   = 1<<7 - 1
    45  	MinInt8   = -1 << 7
    46  	MaxInt16  = 1<<15 - 1
    47  	MinInt16  = -1 << 15
    48  	MaxInt32  = 1<<31 - 1
    49  	MinInt32  = -1 << 31
    50  	MaxInt64  = 1<<63 - 1
    51  	MinInt64  = -1 << 63
    52  	MaxUint   = 1<<intSize - 1
    53  	MaxUint8  = 1<<8 - 1
    54  	MaxUint16 = 1<<16 - 1
    55  	MaxUint32 = 1<<32 - 1
    56  	MaxUint64 = 1<<64 - 1
    57  )
    58
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