U
    L?h                     @   s   d Z ddlmZmZ ddlmZ ddlmZ ddlmZ ddl	m
Z
 ddlmZ dd	lmZ dd
lmZ dd ZG dd dZe Zdd Zedddddd ZeedddZd-ddZdd Zd.dd Zd!d" Zd/d$d%Zd0d'd(Zd)d* Zd+d, ZdS )1z"
Generating and counting primes.

    )bisectbisect_leftcount)array)randint)sqrt   )isprime)
deprecated)as_intc                 C   s   ddl m} t|| S )z Wrapping ceiling in as_int will raise an error if there was a problem
        determining whether the expression was exactly an integer or not.r   )ceiling)Z#sympy.functions.elementary.integersr   r   )ar    r   H/var/www/html/venv/lib/python3.8/site-packages/sympy/ntheory/generate.py_as_int_ceiling   s    r   c                   @   s~   e Zd ZdZdddZdd Zddd	Zd
d Zdd Zdd Z	d ddZ
dd Zdd Zdd Zdd Zdd Zdd ZdS )!Sievea  A list of prime numbers, implemented as a dynamically
    growing sieve of Eratosthenes. When a lookup is requested involving
    an odd number that has not been sieved, the sieve is automatically
    extended up to that number. Implementation details limit the number of
    primes to ``2^32-1``.

    Examples
    ========

    >>> from sympy import sieve
    >>> sieve._reset() # this line for doctest only
    >>> 25 in sieve
    False
    >>> sieve._list
    array('L', [2, 3, 5, 7, 11, 13, 17, 19, 23])
    @B c                    s   d _ tdddddddg _tdd	d
d
dddg _tdd	d
ddd	dg _|d	kr^td| _t fdd j j jfD stdS )z Initial parameters for the Sieve class.

        Parameters
        ==========

        sieve_interval (int): Amount of memory to be used

        Raises
        ======

        ValueError
            If ``sieve_interval`` is not positive.

           L                  r   r	      iz+sieve_interval should be a positive integerc                 3   s   | ]}t | jkV  qd S N)len_n.0r   selfr   r   	<genexpr>C   s     z!Sieve.__init__.<locals>.<genexpr>N)	r!   _array_list_tlist_mlist
ValueErrorsieve_intervalallAssertionError)r%   r,   r   r$   r   __init__-   s    zSieve.__init__c                 C   s   ddt | j| jd | jd | jd | jd | jd dt | j| jd | jd | jd | jd | jd d	t | j| jd | jd | jd | jd | jd f S )
Nzs<%s sieve (%i): %i, %i, %i, ... %i, %i
%s sieve (%i): %i, %i, %i, ... %i, %i
%s sieve (%i): %i, %i, %i, ... %i, %i>primer   r	   r   r   totientmobius)r    r(   r)   r*   r$   r   r   r   __repr__E   s0                zSieve.__repr__Nc                 C   sj   t dd |||fD r$d } }}|r:| jd| j | _|rP| jd| j | _|rf| jd| j | _dS )z]Reset all caches (default). To reset one or more set the
            desired keyword to True.c                 s   s   | ]}|d kV  qd S r   r   r"   r   r   r   r&   V   s     zSieve._reset.<locals>.<genexpr>TN)r-   r(   r!   r)   r*   )r%   r0   r2   r3   r   r   r   _resetS   s    zSieve._resetc              	   C   s   t |}| jd d }||k r"dS |d }||kr^|  jtd| ||7  _||d  }}q*|  jtd| ||d 7  _dS )zGrow the sieve to cover all primes <= n.

        Examples
        ========

        >>> from sympy import sieve
        >>> sieve._reset() # this line for doctest only
        >>> sieve.extend(30)
        >>> sieve[10] == 29
        True
        r   r	   Nr   r   )intr(   r'   _primerange)r%   nnumZnum2r   r   r   extend_   s    zSieve.extendc                 c   s   |d r|d8 }||k rt | j|| d }dg| }| jdt| jt|d|  d  D ]0}t|d |  d | ||D ]}d||< q~q\t|D ]\}}|r|d|  d V  q|d| 7 }qdS )a?   Generate all prime numbers in the range (a, b).

        Parameters
        ==========

        a, b : positive integers assuming the following conditions
                * a is an even number
                * 2 < self._list[-1] < a < b < nextprime(self._list[-1])**2

        Yields
        ======

        p (int): prime numbers such that ``a < p < b``

        Examples
        ========

        >>> from sympy.ntheory.generate import Sieve
        >>> s = Sieve()
        >>> s._list[-1]
        13
        >>> list(s._primerange(18, 31))
        [19, 23, 29]

        r   r	   TFN)minr,   r(   r   r   range	enumerate)r%   r   b
block_sizeblockptidxr   r   r   r7   x   s    
*"zSieve._primerangec                 C   s4   t |}t| j|k r0| t| jd d  qdS )a  Extend to include the ith prime number.

        Parameters
        ==========

        i : integer

        Examples
        ========

        >>> from sympy import sieve
        >>> sieve._reset() # this line for doctest only
        >>> sieve.extend_to_no(9)
        >>> sieve._list
        array('L', [2, 3, 5, 7, 11, 13, 17, 19, 23])

        Notes
        =====

        The list is extended by 50% if it is too short, so it is
        likely that it will be longer than requested.
        r   g      ?N)r   r    r(   r:   r6   )r%   r   r   r   r   extend_to_no   s    zSieve.extend_to_noc                 c   sj   |dkrt |}d}ntdt |}t |}||kr8dS | | | jt| j|t| j| E dH  dS )a(  Generate all prime numbers in the range [2, a) or [a, b).

        Examples
        ========

        >>> from sympy import sieve, prime

        All primes less than 19:

        >>> print([i for i in sieve.primerange(19)])
        [2, 3, 5, 7, 11, 13, 17]

        All primes greater than or equal to 7 and less than 19:

        >>> print([i for i in sieve.primerange(7, 19)])
        [7, 11, 13, 17]

        All primes through the 10th prime

        >>> list(sieve.primerange(prime(10) + 1))
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

        Nr   )r   maxr:   r(   r   )r%   r   r>   r   r   r   
primerange   s    

zSieve.primerangec                 c   sN  t dt|}t|}t| j}||kr,dS ||krRt||D ]}| j| V  q>n|  jtdt||7  _td|D ]j}| j| }||d kr|| d | | }t|||D ] }| j|  | j| | 8  < q||krv|V  qvt||D ]\}| j| }||kr4t|||D ]"}| j|  | j| | 8  < q||kr| j| V  qdS )zGenerate all totient numbers for the range [a, b).

        Examples
        ========

        >>> from sympy import sieve
        >>> print([i for i in sieve.totientrange(7, 18)])
        [6, 4, 6, 4, 10, 4, 12, 6, 8, 8, 16]
        r	   Nr   )rE   r   r    r)   r<   r'   )r%   r   r>   r8   r   ti
startindexjr   r   r   totientrange   s0    




 zSieve.totientrangec                 c   s$  t dt|}t|}t| j}||kr,dS ||krRt||D ]}| j| V  q>n|  jtddg||  7  _td|D ]T}| j| }|| d | | }t|||D ]}| j|  |8  < q||krz|V  qzt||D ]D}| j| }td| ||D ]}| j|  |8  < q||kr|V  qdS )a  Generate all mobius numbers for the range [a, b).

        Parameters
        ==========

        a : integer
            First number in range

        b : integer
            First number outside of range

        Examples
        ========

        >>> from sympy import sieve
        >>> print([i for i in sieve.mobiusrange(7, 18)])
        [-1, 0, 0, 1, -1, 0, -1, 1, 1, 0, -1]
        r	   Nr   r   r   )rE   r   r    r*   r<   r'   )r%   r   r>   r8   r   mirH   rI   r   r   r   mobiusrange  s,    


zSieve.mobiusrangec                 C   sr   t |}t|}|dk r$td| || jd kr<| | t| j|}| j|d  |krb||fS ||d fS dS )a~  Return the indices i, j of the primes that bound n.

        If n is prime then i == j.

        Although n can be an expression, if ceiling cannot convert
        it to an integer then an n error will be raised.

        Examples
        ========

        >>> from sympy import sieve
        >>> sieve.search(25)
        (9, 10)
        >>> sieve.search(23)
        (9, 9)
        r   zn should be >= 2 but got: %sr   r	   N)r   r   r+   r(   r:   r   )r%   r8   testr>   r   r   r   search1  s    
zSieve.searchc              	   C   s^   zt |}|dkstW n ttfk
r2   Y dS X |d dkrH|dkS | |\}}||kS )Nr   Fr   )r   r.   r+   rN   )r%   r8   r   r>   r   r   r   __contains__N  s    zSieve.__contains__c                 c   s   t dD ]}| | V  qd S )Nr	   r   )r%   r8   r   r   r   __iter__Y  s    zSieve.__iter__c                 C   s   t |trV| |j |jdk	r&|jnd}|dk r:td| j|d |jd |j S |dk rftdt|}| | | j|d  S dS )zReturn the nth prime numberNr   r	   zSieve indices start at 1.)	
isinstanceslicerD   stopstart
IndexErrorr(   stepr   )r%   r8   rT   r   r   r   __getitem__]  s    

zSieve.__getitem__)r   )NNN)N)__name__
__module____qualname____doc__r/   r4   r5   r:   r7   rD   rF   rJ   rL   rN   rO   rP   rW   r   r   r   r   r      s   

)
$%,r   c                 C   s   t | }|dk rtd|ttjkr.t| S ddlm} ddlm} d}t	||||||  }||k r|| d? }|||kr|}qf|d }qft
|d }||k rt|r|d7 }|d7 }q|d S )aK   Return the nth prime, with the primes indexed as prime(1) = 2,
        prime(2) = 3, etc.... The nth prime is approximately $n\log(n)$.

        Logarithmic integral of $x$ is a pretty nice approximation for number of
        primes $\le x$, i.e.
        li(x) ~ pi(x)
        In fact, for the numbers we are concerned about( x<1e11 ),
        li(x) - pi(x) < 50000

        Also,
        li(x) > pi(x) can be safely assumed for the numbers which
        can be evaluated by this function.

        Here, we find the least integer m such that li(m) > n using binary search.
        Now pi(m-1) < li(m-1) <= n,

        We find pi(m - 1) using primepi function.

        Starting from m, we have to find n - pi(m-1) more primes.

        For the inputs this implementation can handle, we will have to test
        primality for at max about 10**5 numbers, to get our answer.

        Examples
        ========

        >>> from sympy import prime
        >>> prime(10)
        29
        >>> prime(1)
        2
        >>> prime(100000)
        1299709

        See Also
        ========

        sympy.ntheory.primetest.isprime : Test if n is prime
        primerange : Generate all primes in a given range
        primepi : Return the number of primes less than or equal to n

        References
        ==========

        .. [1] https://en.wikipedia.org/wiki/Prime_number_theorem#Table_of_.CF.80.28x.29.2C_x_.2F_log_x.2C_and_li.28x.29
        .. [2] https://en.wikipedia.org/wiki/Prime_number_theorem#Approximations_for_the_nth_prime_number
        .. [3] https://en.wikipedia.org/wiki/Skewes%27_number
    r	   z-nth must be a positive integer; prime(1) == 2r   loglir   )r   r+   r    siever(   &sympy.functions.elementary.exponentialr]   'sympy.functions.special.error_functionsr_   r6   _primepir
   )nthr8   r]   r_   r   r>   midZn_primesr   r   r   r0   v  s(    1

r0   zgThe `sympy.ntheory.generate.primepi` has been moved to `sympy.functions.combinatorial.numbers.primepi`.z1.13z%deprecated-ntheory-symbolic-functions)Zdeprecated_since_versionZactive_deprecations_targetc                 C   s   ddl m} || S )a
   Represents the prime counting function pi(n) = the number
        of prime numbers less than or equal to n.

        .. deprecated:: 1.13

            The ``primepi`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.primepi`
            instead. See its documentation for more information. See
            :ref:`deprecated-ntheory-symbolic-functions` for details.

        Algorithm Description:

        In sieve method, we remove all multiples of prime p
        except p itself.

        Let phi(i,j) be the number of integers 2 <= k <= i
        which remain after sieving from primes less than
        or equal to j.
        Clearly, pi(n) = phi(n, sqrt(n))

        If j is not a prime,
        phi(i,j) = phi(i, j - 1)

        if j is a prime,
        We remove all numbers(except j) whose
        smallest prime factor is j.

        Let $x= j \times a$ be such a number, where $2 \le a \le i / j$
        Now, after sieving from primes $\le j - 1$,
        a must remain
        (because x, and hence a has no prime factor $\le j - 1$)
        Clearly, there are phi(i / j, j - 1) such a
        which remain on sieving from primes $\le j - 1$

        Now, if a is a prime less than equal to j - 1,
        $x= j \times a$ has smallest prime factor = a, and
        has already been removed(by sieving from a).
        So, we do not need to remove it again.
        (Note: there will be pi(j - 1) such x)

        Thus, number of x, that will be removed are:
        phi(i / j, j - 1) - phi(j - 1, j - 1)
        (Note that pi(j - 1) = phi(j - 1, j - 1))

        $\Rightarrow$ phi(i,j) = phi(i, j - 1) - phi(i / j, j - 1) + phi(j - 1, j - 1)

        So,following recursion is used and implemented as dp:

        phi(a, b) = phi(a, b - 1), if b is not a prime
        phi(a, b) = phi(a, b-1)-phi(a / b, b-1) + phi(b-1, b-1), if b is prime

        Clearly a is always of the form floor(n / k),
        which can take at most $2\sqrt{n}$ values.
        Two arrays arr1,arr2 are maintained
        arr1[i] = phi(i, j),
        arr2[i] = phi(n // i, j)

        Finally the answer is arr2[1]

        Examples
        ========

        >>> from sympy import primepi, prime, prevprime, isprime
        >>> primepi(25)
        9

        So there are 9 primes less than or equal to 25. Is 25 prime?

        >>> isprime(25)
        False

        It is not. So the first prime less than 25 must be the
        9th prime:

        >>> prevprime(25) == prime(9)
        True

        See Also
        ========

        sympy.ntheory.primetest.isprime : Test if n is prime
        primerange : Generate all primes in a given range
        prime : Return the nth prime
    r   )primepi)Z%sympy.functions.combinatorial.numbersrf   )r8   Zfunc_primepir   r   r   rf     s    Xrf   )r8   returnc           	      C   sd  | dk rdS | t jd kr(t | d S t| }dg|d  }dg|d  }td|d D ] }|d ||< | | d ||< qZtd|d D ]}|| ||d  krq||d  }tdt| ||  |d D ]J}|| }||kr||  || | 8  < q||  || |  | 8  < qt||| d }t||dD ]"}||  |||  | 8  < q6q|d S )a   Represents the prime counting function pi(n) = the number
    of prime numbers less than or equal to n.

    Explanation
    ===========

    In sieve method, we remove all multiples of prime p
    except p itself.

    Let phi(i,j) be the number of integers 2 <= k <= i
    which remain after sieving from primes less than
    or equal to j.
    Clearly, pi(n) = phi(n, sqrt(n))

    If j is not a prime,
    phi(i,j) = phi(i, j - 1)

    if j is a prime,
    We remove all numbers(except j) whose
    smallest prime factor is j.

    Let $x= j \times a$ be such a number, where $2 \le a \le i / j$
    Now, after sieving from primes $\le j - 1$,
    a must remain
    (because x, and hence a has no prime factor $\le j - 1$)
    Clearly, there are phi(i / j, j - 1) such a
    which remain on sieving from primes $\le j - 1$

    Now, if a is a prime less than equal to j - 1,
    $x= j \times a$ has smallest prime factor = a, and
    has already been removed(by sieving from a).
    So, we do not need to remove it again.
    (Note: there will be pi(j - 1) such x)

    Thus, number of x, that will be removed are:
    phi(i / j, j - 1) - phi(j - 1, j - 1)
    (Note that pi(j - 1) = phi(j - 1, j - 1))

    $\Rightarrow$ phi(i,j) = phi(i, j - 1) - phi(i / j, j - 1) + phi(j - 1, j - 1)

    So,following recursion is used and implemented as dp:

    phi(a, b) = phi(a, b - 1), if b is not a prime
    phi(a, b) = phi(a, b-1)-phi(a / b, b-1) + phi(b-1, b-1), if b is prime

    Clearly a is always of the form floor(n / k),
    which can take at most $2\sqrt{n}$ values.
    Two arrays arr1,arr2 are maintained
    arr1[i] = phi(i, j),
    arr2[i] = phi(n // i, j)

    Finally the answer is arr2[1]

    Parameters
    ==========

    n : int

    r   r   r   r	   )r`   r(   rN   r   r<   r;   )	r8   ZlimZarr1Zarr2r   rA   rI   stZlim2r   r   r   rc     s.    < "rc   c                 C   sT  t | } t|}|dkr td| dk r4d} |d8 }| tjd krt| \}}|| d ttjk rxtj|| d  S ttjd || ttj S d|k rt|D ]}t| } q| S d| d  }|| kr| d7 } t	| r| S | d7 } n6| | d	kr| d7 } t	| r| S | d7 } n|d	 } t	| r.| S | d7 } t	| rD| S | d7 } q d
S )aU   Return the ith prime greater than n.

        Parameters
        ==========

        n : integer
        ith : positive integer

        Returns
        =======

        int : Return the ith prime greater than n

        Raises
        ======

        ValueError
            If ``ith <= 0``.
            If ``n`` or ``ith`` is not an integer.

        Notes
        =====

        Potential primes are located at 6*j +/- 1. This
        property is used during searching.

        >>> from sympy import nextprime
        >>> [(i, nextprime(i)) for i in range(10, 15)]
        [(10, 11), (11, 13), (12, 13), (13, 17), (14, 17)]
        >>> nextprime(2, ith=2) # the 2nd prime after 2
        5

        See Also
        ========

        prevprime : Return the largest prime smaller than n
        primerange : Generate all primes in a given range

    r   zith should be positiver   r	   r1   r   r   r   r   N)
r6   r   r+   r`   r(   rN   r    	nextprimer<   r
   )r8   Zithr   l_nnr   r   r   ri   u  sD    (





ri   c                 C   s   t | } | dk rtd| dk r4dddddd|  S | tjd krlt| \}}||krdt|d  S t| S d	| d	  }| | dkr|d } t| r| S | d
8 } n|d } t| r| S | d8 } t| r| S | d
8 } qdS )a   Return the largest prime smaller than n.

        Notes
        =====

        Potential primes are located at 6*j +/- 1. This
        property is used during searching.

        >>> from sympy import prevprime
        >>> [(i, prevprime(i)) for i in range(10, 15)]
        [(10, 7), (11, 7), (12, 11), (13, 11), (14, 13)]

        See Also
        ========

        nextprime : Return the ith prime greater than n
        primerange : Generates all primes in a given range
    r   zno preceding primes   r   r   )r   r   r   r   r   r   r	   r   r   N)r   r+   r`   r(   rN   r
   )r8   rj   url   r   r   r   	prevprime  s.    
ro   Nc                 c   s   |dkrd|  } }| |krdS t jd }||krFt | |E dH  dS | |krtt jtt j| d E dH  |d } n| d r| d8 } t||d }| |k rt | |E dH  |} || krdS t| } | |k r| V  qdS qdS )a
   Generate a list of all prime numbers in the range [2, a),
        or [a, b).

        If the range exists in the default sieve, the values will
        be returned from there; otherwise values will be returned
        but will not modify the sieve.

        Examples
        ========

        >>> from sympy import primerange, prime

        All primes less than 19:

        >>> list(primerange(19))
        [2, 3, 5, 7, 11, 13, 17]

        All primes greater than or equal to 7 and less than 19:

        >>> list(primerange(7, 19))
        [7, 11, 13, 17]

        All primes through the 10th prime

        >>> list(primerange(prime(10) + 1))
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

        The Sieve method, primerange, is generally faster but it will
        occupy more memory as the sieve stores values. The default
        instance of Sieve, named sieve, can be used:

        >>> from sympy import sieve
        >>> list(sieve.primerange(1, 30))
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

        Notes
        =====

        Some famous conjectures about the occurrence of primes in a given
        range are [1]:

        - Twin primes: though often not, the following will give 2 primes
                    an infinite number of times:
                        primerange(6*n - 1, 6*n + 2)
        - Legendre's: the following always yields at least one prime
                        primerange(n**2, (n+1)**2+1)
        - Bertrand's (proven): there is always a prime in the range
                        primerange(n, 2*n)
        - Brocard's: there are at least four primes in the range
                        primerange(prime(n)**2, prime(n+1)**2)

        The average gap between primes is log(n) [2]; the gap between
        primes can be arbitrarily large since sequences of composite
        numbers are arbitrarily large, e.g. the numbers in the sequence
        n! + 2, n! + 3 ... n! + n are all composite.

        See Also
        ========

        prime : Return the nth prime
        nextprime : Return the ith prime greater than n
        prevprime : Return the largest prime smaller than n
        randprime : Returns a random prime in a given range
        primorial : Returns the product of primes based on condition
        Sieve.primerange : return range from already computed primes
                           or extend the sieve to contain the requested
                           range.

        References
        ==========

        .. [1] https://en.wikipedia.org/wiki/Prime_number
        .. [2] https://primes.utm.edu/notes/gaps.html
    Nr   r   r	   )r`   r(   rF   r   r;   r7   ri   )r   r>   Zlargest_known_primetailr   r   r   rF     s.    K


rF   c                 C   sX   | |krdS t t| |f\} }t| d |}t|}||krDt|}|| k rTtd|S )aG   Return a random prime number in the range [a, b).

        Bertrand's postulate assures that
        randprime(a, 2*a) will always succeed for a > 1.

        Note that due to implementation difficulties,
        the prime numbers chosen are not uniformly random.
        For example, there are two primes in the range [112, 128),
        ``113`` and ``127``, but ``randprime(112, 128)`` returns ``127``
        with a probability of 15/17.

        Examples
        ========

        >>> from sympy import randprime, isprime
        >>> randprime(1, 30) #doctest: +SKIP
        13
        >>> isprime(randprime(1, 30))
        True

        See Also
        ========

        primerange : Generate all primes in a given range

        References
        ==========

        .. [1] https://en.wikipedia.org/wiki/Bertrand's_postulate

    Nr	   z&no primes exist in the specified range)mapr6   r   ri   ro   r+   )r   r>   r8   rA   r   r   r   	randprime[  s     rr   Tc                 C   sp   |rt | } nt| } | dk r&tdd}|rPtd| d D ]}|t|9 }q<ntd| d D ]}||9 }q^|S )a:  
    Returns the product of the first n primes (default) or
    the primes less than or equal to n (when ``nth=False``).

    Examples
    ========

    >>> from sympy.ntheory.generate import primorial, primerange
    >>> from sympy import factorint, Mul, primefactors, sqrt
    >>> primorial(4) # the first 4 primes are 2, 3, 5, 7
    210
    >>> primorial(4, nth=False) # primes <= 4 are 2 and 3
    6
    >>> primorial(1)
    2
    >>> primorial(1, nth=False)
    1
    >>> primorial(sqrt(101), nth=False)
    210

    One can argue that the primes are infinite since if you take
    a set of primes and multiply them together (e.g. the primorial) and
    then add or subtract 1, the result cannot be divided by any of the
    original factors, hence either 1 or more new primes must divide this
    product of primes.

    In this case, the number itself is a new prime:

    >>> factorint(primorial(4) + 1)
    {211: 1}

    In this case two new primes are the factors:

    >>> factorint(primorial(4) - 1)
    {11: 1, 19: 1}

    Here, some primes smaller and larger than the primes multiplied together
    are obtained:

    >>> p = list(primerange(10, 20))
    >>> sorted(set(primefactors(Mul(*p) + 1)).difference(set(p)))
    [2, 5, 31, 149]

    See Also
    ========

    primerange : Generate all primes in a given range

    r	   zprimorial argument must be >= 1r   )r   r6   r+   r<   r0   rF   )r8   rd   rA   r   r   r   r   	primorial  s    2

rs   Fc           
      c   s   t |pd}d }}|| | }}d}|r0|V  ||kr|rD||k r|d7 }||krd|}|d9 }d}|rn|V  | |}|d7 }q0|r||kr|rdS |dfV  dS |sd}	| }}t|D ]}| |}q||kr| |}| |}|	d7 }	q||	fV  dS )aw  For a given iterated sequence, return a generator that gives
    the length of the iterated cycle (lambda) and the length of terms
    before the cycle begins (mu); if ``values`` is True then the
    terms of the sequence will be returned instead. The sequence is
    started with value ``x0``.

    Note: more than the first lambda + mu terms may be returned and this
    is the cost of cycle detection with Brent's method; there are, however,
    generally less terms calculated than would have been calculated if the
    proper ending point were determined, e.g. by using Floyd's method.

    >>> from sympy.ntheory.generate import cycle_length

    This will yield successive values of i <-- func(i):

        >>> def gen(func, i):
        ...     while 1:
        ...         yield i
        ...         i = func(i)
        ...

    A function is defined:

        >>> func = lambda i: (i**2 + 1) % 51

    and given a seed of 4 and the mu and lambda terms calculated:

        >>> next(cycle_length(func, 4))
        (6, 3)

    We can see what is meant by looking at the output:

        >>> iter = cycle_length(func, 4, values=True)
        >>> list(iter)
        [4, 17, 35, 2, 5, 26, 14, 44, 50, 2, 5, 26, 14]

    There are 6 repeating values after the first 3.

    If a sequence is suspected of being longer than you might wish, ``nmax``
    can be used to exit early (and mu will be returned as None):

        >>> next(cycle_length(func, 4, nmax = 4))
        (4, None)
        >>> list(cycle_length(func, 4, nmax = 4, values=True))
        [4, 17, 35, 2]

    Code modified from:
        https://en.wikipedia.org/wiki/Cycle_detection.
    r   r	   r   N)r6   r<   )
fZx0ZnmaxvaluespowerZlamZtortoiseZharer   mur   r   r   cycle_length  s>    3



rx   c           	   
   C   sv  t | }|dk rtdddddddd	d
ddg
}|dkrD||d  S dtjd  }}||t| d kr||d k r|| d? }|t| d |kr|}qh|}qht|r|d8 }|S ddlm} ddlm	} d}t
||||||  }||k r(|| d? }||| d |kr|}q|d }q|t| d }||kr`t|sT|d8 }|d8 }q8t|rr|d8 }|S )a   Return the nth composite number, with the composite numbers indexed as
        composite(1) = 4, composite(2) = 6, etc....

        Examples
        ========

        >>> from sympy import composite
        >>> composite(36)
        52
        >>> composite(1)
        4
        >>> composite(17737)
        20000

        See Also
        ========

        sympy.ntheory.primetest.isprime : Test if n is prime
        primerange : Generate all primes in a given range
        primepi : Return the number of primes less than or equal to n
        prime : Return the nth prime
        compositepi : Return the number of positive composite numbers less than or equal to n
    r	   z1nth must be a positive integer; composite(1) == 4r   r   rm   	   
                  r   r   r\   r^   )r   r+   r`   r(   rc   r
   ra   r]   rb   r_   r6   )	rd   r8   Zcomposite_arrr   r>   re   r]   r_   Zn_compositesr   r   r   	composite!  sB    




r   c                 C   s$   t | } | dk rdS | t|  d S )ak   Return the number of positive composite numbers less than or equal to n.
        The first positive composite is 4, i.e. compositepi(4) = 1.

        Examples
        ========

        >>> from sympy import compositepi
        >>> compositepi(25)
        15
        >>> compositepi(1000)
        831

        See Also
        ========

        sympy.ntheory.primetest.isprime : Test if n is prime
        primerange : Generate all primes in a given range
        prime : Return the nth prime
        primepi : Return the number of primes less than or equal to n
        composite : Return the nth composite number
    r   r   r	   )r6   rc   )r8   r   r   r   compositepib  s    r   )r	   )N)T)NF) r[   r   r   	itertoolsr   r   r'   Zsympy.core.randomr   Zsympy.external.gmpyr   Z	primetestr
   Zsympy.utilities.decoratorr   Zsympy.utilities.miscr   r   r   r`   r0   rf   r6   rc   ri   ro   rF   rr   rs   rx   r   r   r   r   r   r   <module>   s8     [K
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