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mirror of https://github.com/vlang/v.git synced 2023-08-10 21:13:21 +03:00
v/vlib/math/math.v
Kriyszig 801e06318f Factorial doesn't accept negative numbers
Previously factorial could accept negative number which isn't defined
2019-07-04 12:59:06 +02:00

236 lines
4.9 KiB
Go

// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module math
const (
E = 2.71828182845904523536028747135266249775724709369995957496696763
Pi = 3.14159265358979323846264338327950288419716939937510582097494459
Phi = 1.61803398874989484820458683436563811772030917980576286213544862
Tau = 6.28318530717958647692528676655900576839433879875021164194988918
Sqrt2 = 1.41421356237309504880168872420969807856967187537694807317667974
SqrtE = 1.64872127070012814684865078781416357165377610071014801157507931
SqrtPi = 1.77245385090551602729816748334114518279754945612238712821380779
SqrtTau = 2.50662827463100050241576528481104525300698674060993831662992357
SqrtPhi = 1.27201964951406896425242246173749149171560804184009624861664038
Ln2 = 0.693147180559945309417232121458176568075500134360255254120680009
Log2E = 1.0 / Ln2
Ln10 = 2.30258509299404568401799145468436420760110148862877297603332790
Log10E = 1.0 / Ln10
)
// Returns the absolute value.
pub fn abs(a f64) f64 {
if a < 0 {
return -a
}
return a
}
// acos calculates inversed cosine (arccosine).
pub fn acos(a f64) f64 {
return C.acos(a)
}
// asin calculates inversed sine (arcsine).
pub fn asin(a f64) f64 {
return C.asin(a)
}
// atan calculates inversed tangent (arctangent).
pub fn atan(a f64) f64 {
return C.atan(a)
}
// atan2 calculates inverseed tangent with two arguments, returns angle between the X axis and the point.
pub fn atan2(a, b f64) f64 {
return C.atan2(a, b)
}
// cbrt calculates cubic root.
pub fn cbrt(a f64) f64 {
return C.cbrt(a)
}
// ceil returns the nearest integer equal or higher to the provided value.
pub fn ceil(a f64) f64 {
return C.ceil(a)
}
// cos calculates cosine.
pub fn cos(a f64) f64 {
return C.cos(a)
}
// cosh calculates hyperbolic cosine.
pub fn cosh(a f64) f64 {
return C.cosh(a)
}
// exp calculates exponement of the number (math.pow(math.E, a)).
pub fn exp(a f64) f64 {
return C.exp(a)
}
// digits returns an array of the digits of n in the given base.
pub fn digits(n, base int) []int {
mut sign := 1
if n < 0 {
sign = -1
n = -n
}
mut res := []int
for n != 0 {
res << (n % base) * sign
n /= base
}
return res
}
// exp2 returns the base-2 exponential function of a (math.pow(2, a)).
pub fn exp2(a f64) f64 {
return C.exp2(a)
}
// floor returns the nearest integer equal or lower of the provided value.
pub fn floor(a f64) f64 {
return C.floor(a)
}
// fmod returns the floating-point remainder of number / denom (rounded towards zero):
pub fn fmod(a, b f64) f64 {
return C.fmod(a, b)
}
// gcd calculates greatest common (positive) divisor (or zero if a and b are both zero).
pub fn gcd(a, b i64) i64 {
if a < 0 {
a = -a
}
if b < 0 {
b = -b
}
for b != 0 {
a %= b
if a == 0 {
return b
}
b %= a
}
return a
}
// lcm calculates least common (non-negative) multiple.
pub fn lcm(a, b i64) i64 {
if a == 0 {
return a
}
res := a * (b / gcd(b, a))
if res < 0 {
return -res
}
return res
}
// log calculates natural (base e) logarithm of the provided value.
pub fn log(a f64) f64 {
return C.log(a)
}
// log2 calculates base-2 logarithm of the provided value.
pub fn log2(a f64) f64 {
return C.log(a) / C.log(2)
}
// log10 calculates the common (base-10) logarithm of the provided value.
pub fn log10(a f64) f64 {
return C.log10(a)
}
// log_n calculates base-N logarithm of the provided value.
pub fn log_n(a, b f64) f64 {
return C.log(a) / C.log(b)
}
// max returns the maximum value of the two provided.
pub fn max(a, b f64) f64 {
if a > b {
return a
}
return b
}
// min returns the minimum value of all the values provided.
pub fn min(a, b f64) f64 {
if a < b {
return a
}
return b
}
// pow returns base raised to the provided power.
pub fn pow(a, b f64) f64 {
return C.pow(a, b)
}
// radians convert from radians to degrees.
pub fn radians(degrees f64) f64 {
return degrees * (Pi / 180.0)
}
// degrees convert from degrees to radians.
pub fn degrees(radians f64) f64 {
return radians * (180.0 / Pi)
}
// round returns the integer nearest to the provided value.
pub fn round(f f64) f64 {
return C.round(f)
}
// sin calculates sine.
pub fn sin(a f64) f64 {
return C.sin(a)
}
// sinh calculates hyperbolic sine.
pub fn sinh(a f64) f64 {
return C.sinh(a)
}
// sqrt calculates square of the provided value.
pub fn sqrt(a f64) f64 {
return C.sqrt(a)
}
// tan calculates tangent.
pub fn tan(a f64) f64 {
return C.tan(a)
}
// tanh calculates hyperbolic tangent.
pub fn tanh(a f64) f64 {
return C.tanh(a)
}
// trunc rounds a toward zero, returning the nearest integral value that is not
// larger in magnitude than a.
pub fn trunc(a f64) f64 {
return C.trunc(a)
}
// factorial calculates the factorial of the provided value.
pub fn factorial(a int) i64 {
if a < 0 {
panic('factorial: Cannot find factorial of negative number')
}
mut prod := 1
for i:= 0; i < a; i++ {
prod *= (i+1)
}
return prod
}