Integer roots: Difference between revisions
Content added Content deleted
m (→{{header|Haskell}}: An earlier reversion reverted) |
(→{{header|Phix}}: now uses mpz_root() instead) |
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{{libheader|mpfr}} |
{{libheader|mpfr}} |
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<lang Phix>include mpfr.e |
<lang Phix>include mpfr.e |
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function integer_root(integer n, object |
function integer_root(integer n, object a) |
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-- a must be integer or string |
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-- yields the nth root of A, adapted from https://en.wikipedia.org/wiki/Nth_root_algorithm |
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mpz res = mpz_init( |
mpz res = mpz_init() |
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{} = mpz_root(res,mpz_init(a),n) |
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delta = mpz_init() |
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A = mpz_init(A) |
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while true do |
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mpz_set(x,A) |
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mpz_pow_ui(delta,res,n-1) |
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mpz_fdiv_q(x, x, delta) |
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mpz_sub(delta,x,res) |
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{} = mpz_fdiv_q_ui(delta, delta, n) |
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if mpz_cmp_si(delta,0)=0 then exit end if |
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mpz_add(res,res,delta) |
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end while |
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return mpz_get_str(res) |
return mpz_get_str(res) |
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end function |
end function |
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3rd root of 8 = 2 |
3rd root of 8 = 2 |
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3rd root of 9 = 2 |
3rd root of 9 = 2 |
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First digits of the square root of 2: |
First digits of the square root of 2: 14142135623730950488...47107578486024636008 (2,001 digits) |
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First digits of the cube root of 2: |
First digits of the cube root of 2: 12599210498948731647...22546828353183047061 (2,001 digits) |
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</pre> |
</pre> |
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