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author | 2025-03-09 17:47:56 +0100 | |
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committer | 2025-03-10 01:59:49 +0100 | |
commit | 3ac1ee16f377d31a0fb80c8dae28b6239ac4229e (patch) | |
tree | f61faa581feaaeaba2542b9f2b8234a590684413 /vendor/modernc.org/mathutil/primes.go | |
parent | [chore] update URLs to forked source (diff) | |
download | gotosocial-3ac1ee16f377d31a0fb80c8dae28b6239ac4229e.tar.xz |
[chore] remove vendor
Diffstat (limited to 'vendor/modernc.org/mathutil/primes.go')
-rw-r--r-- | vendor/modernc.org/mathutil/primes.go | 331 |
1 files changed, 0 insertions, 331 deletions
diff --git a/vendor/modernc.org/mathutil/primes.go b/vendor/modernc.org/mathutil/primes.go deleted file mode 100644 index ec1e5f5a5..000000000 --- a/vendor/modernc.org/mathutil/primes.go +++ /dev/null @@ -1,331 +0,0 @@ -// Copyright (c) 2014 The mathutil Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package mathutil // import "modernc.org/mathutil" - -import ( - "math" -) - -// IsPrimeUint16 returns true if n is prime. Typical run time is few ns. -func IsPrimeUint16(n uint16) bool { - return n > 0 && primes16[n-1] == 1 -} - -// NextPrimeUint16 returns first prime > n and true if successful or an -// undefined value and false if there is no next prime in the uint16 limits. -// Typical run time is few ns. -func NextPrimeUint16(n uint16) (p uint16, ok bool) { - return n + uint16(primes16[n]), n < 65521 -} - -// IsPrime returns true if n is prime. Typical run time is about 100 ns. -func IsPrime(n uint32) bool { - switch { - case n&1 == 0: - return n == 2 - case n%3 == 0: - return n == 3 - case n%5 == 0: - return n == 5 - case n%7 == 0: - return n == 7 - case n%11 == 0: - return n == 11 - case n%13 == 0: - return n == 13 - case n%17 == 0: - return n == 17 - case n%19 == 0: - return n == 19 - case n%23 == 0: - return n == 23 - case n%29 == 0: - return n == 29 - case n%31 == 0: - return n == 31 - case n%37 == 0: - return n == 37 - case n%41 == 0: - return n == 41 - case n%43 == 0: - return n == 43 - case n%47 == 0: - return n == 47 - case n%53 == 0: - return n == 53 // Benchmarked optimum - case n < 65536: - // use table data - return IsPrimeUint16(uint16(n)) - default: - mod := ModPowUint32(2, (n+1)/2, n) - if mod != 2 && mod != n-2 { - return false - } - blk := &lohi[n>>24] - lo, hi := blk.lo, blk.hi - for lo <= hi { - index := (lo + hi) >> 1 - liar := liars[index] - switch { - case n > liar: - lo = index + 1 - case n < liar: - hi = index - 1 - default: - return false - } - } - return true - } -} - -// IsPrimeUint64 returns true if n is prime. Typical run time is few tens of µs. -// -// SPRP bases: http://miller-rabin.appspot.com -func IsPrimeUint64(n uint64) bool { - switch { - case n%2 == 0: - return n == 2 - case n%3 == 0: - return n == 3 - case n%5 == 0: - return n == 5 - case n%7 == 0: - return n == 7 - case n%11 == 0: - return n == 11 - case n%13 == 0: - return n == 13 - case n%17 == 0: - return n == 17 - case n%19 == 0: - return n == 19 - case n%23 == 0: - return n == 23 - case n%29 == 0: - return n == 29 - case n%31 == 0: - return n == 31 - case n%37 == 0: - return n == 37 - case n%41 == 0: - return n == 41 - case n%43 == 0: - return n == 43 - case n%47 == 0: - return n == 47 - case n%53 == 0: - return n == 53 - case n%59 == 0: - return n == 59 - case n%61 == 0: - return n == 61 - case n%67 == 0: - return n == 67 - case n%71 == 0: - return n == 71 - case n%73 == 0: - return n == 73 - case n%79 == 0: - return n == 79 - case n%83 == 0: - return n == 83 - case n%89 == 0: - return n == 89 // Benchmarked optimum - case n <= math.MaxUint16: - return IsPrimeUint16(uint16(n)) - case n <= math.MaxUint32: - return ProbablyPrimeUint32(uint32(n), 11000544) && - ProbablyPrimeUint32(uint32(n), 31481107) - case n < 105936894253: - return ProbablyPrimeUint64_32(n, 2) && - ProbablyPrimeUint64_32(n, 1005905886) && - ProbablyPrimeUint64_32(n, 1340600841) - case n < 31858317218647: - return ProbablyPrimeUint64_32(n, 2) && - ProbablyPrimeUint64_32(n, 642735) && - ProbablyPrimeUint64_32(n, 553174392) && - ProbablyPrimeUint64_32(n, 3046413974) - case n < 3071837692357849: - return ProbablyPrimeUint64_32(n, 2) && - ProbablyPrimeUint64_32(n, 75088) && - ProbablyPrimeUint64_32(n, 642735) && - ProbablyPrimeUint64_32(n, 203659041) && - ProbablyPrimeUint64_32(n, 3613982119) - default: - return ProbablyPrimeUint64_32(n, 2) && - ProbablyPrimeUint64_32(n, 325) && - ProbablyPrimeUint64_32(n, 9375) && - ProbablyPrimeUint64_32(n, 28178) && - ProbablyPrimeUint64_32(n, 450775) && - ProbablyPrimeUint64_32(n, 9780504) && - ProbablyPrimeUint64_32(n, 1795265022) - } -} - -// NextPrime returns first prime > n and true if successful or an undefined value and false if there -// is no next prime in the uint32 limits. Typical run time is about 2 µs. -func NextPrime(n uint32) (p uint32, ok bool) { - switch { - case n < 65521: - p16, _ := NextPrimeUint16(uint16(n)) - return uint32(p16), true - case n >= math.MaxUint32-4: - return - } - - n++ - var d0, d uint32 - switch mod := n % 6; mod { - case 0: - d0, d = 1, 4 - case 1: - d = 4 - case 2, 3, 4: - d0, d = 5-mod, 2 - case 5: - d = 2 - } - - p = n + d0 - if p < n { // overflow - return - } - - for { - if IsPrime(p) { - return p, true - } - - p0 := p - p += d - if p < p0 { // overflow - break - } - - d ^= 6 - } - return -} - -// NextPrimeUint64 returns first prime > n and true if successful or an undefined value and false if there -// is no next prime in the uint64 limits. Typical run time is in hundreds of µs. -func NextPrimeUint64(n uint64) (p uint64, ok bool) { - switch { - case n < 65521: - p16, _ := NextPrimeUint16(uint16(n)) - return uint64(p16), true - case n >= 18446744073709551557: // last uint64 prime - return - } - - n++ - var d0, d uint64 - switch mod := n % 6; mod { - case 0: - d0, d = 1, 4 - case 1: - d = 4 - case 2, 3, 4: - d0, d = 5-mod, 2 - case 5: - d = 2 - } - - p = n + d0 - if p < n { // overflow - return - } - - for { - if ok = IsPrimeUint64(p); ok { - break - } - - p0 := p - p += d - if p < p0 { // overflow - break - } - - d ^= 6 - } - return -} - -// FactorTerm is one term of an integer factorization. -type FactorTerm struct { - Prime uint32 // The divisor - Power uint32 // Term == Prime^Power -} - -// FactorTerms represent a factorization of an integer -type FactorTerms []FactorTerm - -// FactorInt returns prime factorization of n > 1 or nil otherwise. -// Resulting factors are ordered by Prime. Typical run time is few µs. -func FactorInt(n uint32) (f FactorTerms) { - switch { - case n < 2: - return - case IsPrime(n): - return []FactorTerm{{n, 1}} - } - - f, w := make([]FactorTerm, 9), 0 - for p := 2; p < len(primes16); p += int(primes16[p]) { - if uint(p*p) > uint(n) { - break - } - - power := uint32(0) - for n%uint32(p) == 0 { - n /= uint32(p) - power++ - } - if power != 0 { - f[w] = FactorTerm{uint32(p), power} - w++ - } - if n == 1 { - break - } - } - if n != 1 { - f[w] = FactorTerm{n, 1} - w++ - } - return f[:w] -} - -// PrimorialProductsUint32 returns a slice of numbers in [lo, hi] which are a -// product of max 'max' primorials. The slice is not sorted. -// -// See also: http://en.wikipedia.org/wiki/Primorial -func PrimorialProductsUint32(lo, hi, max uint32) (r []uint32) { - lo64, hi64 := int64(lo), int64(hi) - if max > 31 { // N/A - max = 31 - } - - var f func(int64, int64, uint32) - f = func(n, p int64, emax uint32) { - e := uint32(1) - for n <= hi64 && e <= emax { - n *= p - if n >= lo64 && n <= hi64 { - r = append(r, uint32(n)) - } - if n < hi64 { - p, _ := NextPrime(uint32(p)) - f(n, int64(p), e) - } - e++ - } - } - - f(1, 2, max) - return -} |