Source file src/math/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             = 3.40282346638528859811704183484516925440e+38  // 2**127 * (2**24 - 1) / 2**23
    32		SmallestNonzeroFloat32 = 1.401298464324817070923729583289916131280e-45 // 1 / 2**(127 - 1 + 23)
    33	
    34		MaxFloat64             = 1.797693134862315708145274237317043567981e+308 // 2**1023 * (2**53 - 1) / 2**52
    35		SmallestNonzeroFloat64 = 4.940656458412465441765687928682213723651e-324 // 1 / 2**(1023 - 1 + 52)
    36	)
    37	
    38	// Integer limit values.
    39	const (
    40		MaxInt8   = 1<<7 - 1
    41		MinInt8   = -1 << 7
    42		MaxInt16  = 1<<15 - 1
    43		MinInt16  = -1 << 15
    44		MaxInt32  = 1<<31 - 1
    45		MinInt32  = -1 << 31
    46		MaxInt64  = 1<<63 - 1
    47		MinInt64  = -1 << 63
    48		MaxUint8  = 1<<8 - 1
    49		MaxUint16 = 1<<16 - 1
    50		MaxUint32 = 1<<32 - 1
    51		MaxUint64 = 1<<64 - 1
    52	)
    53	

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