github.com/ccccaoqing/test@v0.0.0-20220510085219-3985d23445c0/src/math/const.go (about)

     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  package math
     7  
     8  // Mathematical constants.
     9  // Reference: http://oeis.org/Axxxxxx
    10  const (
    11  	E   = 2.71828182845904523536028747135266249775724709369995957496696763 // A001113
    12  	Pi  = 3.14159265358979323846264338327950288419716939937510582097494459 // A000796
    13  	Phi = 1.61803398874989484820458683436563811772030917980576286213544862 // A001622
    14  
    15  	Sqrt2   = 1.41421356237309504880168872420969807856967187537694807317667974 // A002193
    16  	SqrtE   = 1.64872127070012814684865078781416357165377610071014801157507931 // A019774
    17  	SqrtPi  = 1.77245385090551602729816748334114518279754945612238712821380779 // A002161
    18  	SqrtPhi = 1.27201964951406896425242246173749149171560804184009624861664038 // A139339
    19  
    20  	Ln2    = 0.693147180559945309417232121458176568075500134360255254120680009 // A002162
    21  	Log2E  = 1 / Ln2
    22  	Ln10   = 2.30258509299404568401799145468436420760110148862877297603332790 // A002392
    23  	Log10E = 1 / Ln10
    24  )
    25  
    26  // Floating-point limit values.
    27  // Max is the largest finite value representable by the type.
    28  // SmallestNonzero is the smallest positive, non-zero value representable by the type.
    29  const (
    30  	MaxFloat32             = 3.40282346638528859811704183484516925440e+38  // 2**127 * (2**24 - 1) / 2**23
    31  	SmallestNonzeroFloat32 = 1.401298464324817070923729583289916131280e-45 // 1 / 2**(127 - 1 + 23)
    32  
    33  	MaxFloat64             = 1.797693134862315708145274237317043567981e+308 // 2**1023 * (2**53 - 1) / 2**52
    34  	SmallestNonzeroFloat64 = 4.940656458412465441765687928682213723651e-324 // 1 / 2**(1023 - 1 + 52)
    35  )
    36  
    37  // Integer limit values.
    38  const (
    39  	MaxInt8   = 1<<7 - 1
    40  	MinInt8   = -1 << 7
    41  	MaxInt16  = 1<<15 - 1
    42  	MinInt16  = -1 << 15
    43  	MaxInt32  = 1<<31 - 1
    44  	MinInt32  = -1 << 31
    45  	MaxInt64  = 1<<63 - 1
    46  	MinInt64  = -1 << 63
    47  	MaxUint8  = 1<<8 - 1
    48  	MaxUint16 = 1<<16 - 1
    49  	MaxUint32 = 1<<32 - 1
    50  	MaxUint64 = 1<<64 - 1
    51  )