# linear congruential generator class python

The combination of two or more LCGs into one random number generator can result in a marked increase in the period length of the generator which makes them better suited for simulating more complex systems. generator with the given parameters above. The generator is defined by the recurrence relation: X n+1 = (aX n + c) mod m where X is the sequence of pseudo-random values m, 0 < m - modulus a, 0 < a < m - multiplier c, 0 ≤ c < m - increment x 0, 0 ≤ x 0 < m - the seed or start value. The generation of random numbers plays a large role in many applications ranging from cryptography to Monte Carlo methods. class random.SystemRandom ([seed]) ¶ Class that uses the os.urandom() function for generating random … a The multiplier parameter (a) used in the transition algorithm. Python's Random Function" print" 2. One of the most common algorithms for generating random numbers is the linear congruential generator… Linear congruential generator in … The java.util.Random class instance is used to generate a stream of pseudorandom numbers. The algorithms implemented by class Random use a protected utility method that on each invocation can supply up to 32 pseudo randomly generated bits. Active 5 months ago. Our next task is to implement a linear congruential generator algorithm as a means for creating our uniform random draws. Constructs a linear_congruential_engine object, and initializes its internal state value:. better and faster pseudorandom number generators. This time I'll focus on one specific kind of PRNGs - Linear Congruential Generators. Linear congruential generators (LCG) ¶. The class did not go into the details of how it was broken and left it as a … methods such as the Mersenne Twister are much more common in practical We use optional third-party analytics cookies to understand how you use GitHub.com so we can build better products. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. Clone with Git or checkout with SVN using the repository’s web address. The number $$z_0$$ is called the seed, and setting it allows us to have a reproducible … The PCG64 state vector consists of 2 unsigned 128-bit values, which are represented externally as Python ints. … Linear Congruential Method is a class of Pseudo Random Number Generator (PRNG) algorithms used for generating sequences of random-like numbers in a specific range. with care, then the … We generate the next random integer using the … congruential generators are one of the oldest and most well-known the 'best' parameters to use. Linear congruential generator You are encouraged to solve this task according to the task description, using any language you may know. Construct an RNG using the specified generator, if generatorOrSeed is an instance of PrimitiveRandomNumberGenerator.If generator_or_seed is an … If m is not zero, this parameter should be … Everything that comes to my mind is: Diehard, chi-square, kol-smirnov and that's obviously enough for my purposes (its a homework) but I have read some articles and documentation about these tests to better understand them, but it is still quite abstract for me to write this in the form of a Python code. The generator … The random numbers generated by linear_congruential_engine have a period of m. Template parameters UIntType An unsigned integer type. Implement hash table using linear congruential probing in python. So I decided to implement my hash table with … Tables of linear congruential generators of different sizes and good lattice structure. The Mersenne Twister is used in below systems or libraries: Python, Ruby, R, PHP, Common Lisp, C++ Boost, Julia, Octave, Excel, Mathematica, etc. Additive Congruential Method is a type of linear congruential generator for generating pseudorandom numbers in a specific range. The circuit is derived from LCG algorithm proposed by Lehmer. Question: Linear Congruential Random Number Generator Implement C/Java/Python Programs That Can Find The Cycle Length Of A Linear Congruential Random Number Generator, Using Floyd's Algorithm. Working code implemented in Python and appropriate comments provided for better understanding. Random ([seed]) ¶ Class that implements the default pseudo-random number generator used by the random module. Linear congruential generators (LCGs) are a class of pseudorandom number The Terms In The Problem Statement Are Likely To Be Unfamiliar To You, But They Are Not Difficult To Understand And Are Described In Detail Below. theory and optimal selection of a seed number are beyond the scope of Several nets Please can you help me to make equidistribution test (Cnut test) of this generator? Army Research Lab. Linear congruential generators are one of the oldest and most well-known methods for generating … state = seed # … requirement, random number generators today are not truly 'random.' Linear congruential generator (LCG) 1958 W. E. Thomson; A. Rotenberg ... e.g. c and m are relatively prime, a − 1 is divisible by all prime factors of m. a − 1 is a multiple of 4 if m is a multiple of 4. If m is not zero, this parameter should be lower than m. c The increment parameter (c) used in the transition algorithm. Read more . The input seed is processed by SeedSequence to generate both values. Random number generators such as LCGs are known as 'pseudorandom' as Predicting a linear congruential generator LCGs are used in web applications to create quick and easy pseudo-random numbers. People like it because it's easy to understand and easily implemented. codeviking.random Package¶ class RNG (generator_or_seed) [source] ¶. z i + 1 = ( a z i + c) mod m. Hull-Dobell Theorem: The LCG will have a full period for all seeds if and only if. General Congruential Generators • Linear Congruential Generators are a special case of generators defined by: • where g() is a function of previous X i’s • X i ∈ [0, m-1], R i = X i /m • Quadratic congruential generator • Defined by: • Multiple recursive generators • Defined by: • Fibonacci generator understand and verify through simulation the Central Limit Theorem. Linear Congruential Generator Implementation. Here's the code: #include … Generating successively longer vectors using the 'poor' LCG and plotting Python uses the standard Wichmann-Hill generator, combining three pure multiplicative congruential generators of modulus 30269, 30307 and 30323. Linear Inversive congruential generator (ICG) 1986 J. Eichenauer and J. Lehn Park-Miller generator: 1988 S. K. Park and K. W. Miller A specific … Linear Congruential Generator is most common and oldest algorithm for generating pseudo-randomized numbers. The generation of random numbers plays a large role in many applications ranging from cryptography to Monte Carlo methods. The second is a fixed odd increment used in the LCG. Quantity or dimension of the generator: Many of the options pricers we have already created require more than a single random number in order to be accurately priced. For more information, see our Privacy Statement. package is used to Learn more, We use analytics cookies to understand how you use our websites so we can make them better, e.g. The method represents one of the oldest and best-known pseudorandom number generator algorithms. as we did previously, we see the generated points are very sequentially This is an excerpt from the Python Data Science Handbook by Jake VanderPlas; Jupyter notebooks are available on GitHub. A class that uses a PrimitiveRandomNumberGenerator to provide several higher-level random number generator methods. C++ Server Side Programming Programming. Linear Congruential Random Number Generator Implement C/Java/Python programs that can find the cycle length of a linear congruential random number generator, using Floyd's algorithm. take the current system time in microseconds. they're used to log you in. A Linear congruential generator (LCG) is a class of pseudorandom number generator (PRNG) algorithms used for generating sequences of random-like numbers. The theory behind them is relatively easy to understand, and they are easily implemented and fast, especially on computer hardware which can provide modular arithmetic by storage-bit truncation. If you find this content useful, please consider supporting the work by buying the book! The linear … Many best in class pseudo random generators grouped into one simple library. The plot3d Class participation: Aspects include attending class, ... understand and use Python list comprehensions and generators. If one chooses the values of , and . The combination of two or more LCGs into one random number generator can result in a marked increase in the period length of the generator which makes them better suited for simulating more complex systems. Its state is a single integer value, with the following transition algorithm: This is the c… Linear congruential generators (LCG)¶ $$z_{i+1} = (az_i + c) \mod m$$ Hull-Dobell Theorem: The LCG will have a full period for all seeds if and onlh if $$c$$ and $$m$$ are relatively prime, $$a - 1$$ is divisible by all prime factors of $$m$$ $$a - 1$$ is a multiple of 4 if $$m$$ is a multiple of 4. The second is a fixed odd increment used in the LCG. The period of LCG depends on the parameter. It picks two hardcoded yet arbitrary values from a discrete stream of time and uses them to create a unique system by which to choose a number from 0 to 9. 128-bit Linear Congruential Generator (LCG) with Output Mixing¶ class randomgen.pcg64. Add Linear Congruential Generator #156 harshildarji merged 1 commit into TheAlgorithms : master from unknown repository Oct 20, 2017 Conversation 0 Commits 1 Checks 0 Files changed Title in article class not centered The following function is an implementation of a linear congruential Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. comprehensive list of the The latter function would typically be called by an end user to generate random numbers within a given interval. $$n$$ increases. Recently I came across Linear Congruential Generators (LCG) while taking an online course in Cryptography. Customizable 128-bit LCG bit generator with output mixing. A linear congruential generator is an algorithm that yields a sequence of pseudo-randomized numbers calculated with a discontinuous piecewise linear equation. The class uses a 48-bit seed, which is modified using a linear congruential formula. The authors implemented hash sets using linear probing. Hello. multiplier, and $$c$$ the increment. The PCG64 state vector consists of 2 unsigned 128-bit values, which are represented externally as Python ints. Many best in class pseudo random generators grouped into one simple library. __init__ (generator_or_seed) [source] ¶. Alternative Generator¶ class random. We can use the function to generate random numbers $$U(0,â1)$$. These are not directly consumable in Python and must be consumed by a Generator or similar object that supports low-level access. # Genera e visualizza la sequenza di m-1 valori, # Visualizzazione pattern mediante un'immagine. Linear Congruential Generator with RANDU initial settings" print "" print" (or type 'q' to quit)" print "" def select_number_of_observations (): """ Command line prompt to select the number of observations for a given test:return: void - prints a prompt to command line """ Support changing the LCG’s multiplier and the output function, including support for user-defined output functions. sample generation in 3 dimensions. The primary considerations of this interface are as follows: 1. + Linear Congruential Generator + Combined Linear Congruential Generators + Lehmer Random Number Generator (Multiplicative Congruential Generator) * Set Theory - Extensions to Python set class - Multiple union and intersection operations - Cartesian products - Relative Complements of multiple sets * Statistics - Factor Analysis - ANOVA and MANOVA - Hypothesis Testing - Covariance and Correlation … Python implementation of the LCG (Linear Congruential Generator) for generating pseudo-random numbers. 14.2.1 Linear Congruential Generators Linear congruential generators (LCG) are a form of random number generator based on the following general recurrence relation: x … Linear Congruential Generator. The java.util.Random class instance is used to generate a stream of pseudorandom numbers. congruential generator are the same as the ANSI C implementation - lcg.py As $$n$$ increases, the LCG appears to be 'random' enough as demonstrated This is the simplest generator engine in the standard library. numbers. applications ranging from cryptography to Monte Carlo methods. Linear Congruential Generator in Python. The Multiplicative congruential generators, also known as Lehmer random number generators, is a type of linear congruential generator for generating pseudorandom numbers in $U(0, 1)$. You can always update your selection by clicking Cookie Preferences at the bottom of the page. Linear Congruential Method is a class of Pseudo Random Number Generator (PRNG) algorithms used for generating sequences of random-like numbers in a specific range. The Mersenne Twister is one of the most extensively tested random number generators in existence. The LCG or linear congruential generator is yet another pseudo-random number generator calculated with a discontinuous piecewise linear equation. library random python3 random-generation free random-number-generators mit-license mersenne-twister lcg linear-congruential-generator pseudo-random mit-licensed prg multiple … Linear congruential generators are defined by a recurrence relation: There are many choices for the parameters $$m$$, the modulus, $$a$$, the methods for generating random numbers primarily due to their comparative We use optional third-party analytics cookies to understand how you use GitHub.com so we can build better products. Linear Congruential Generator "print" 3. One of the simplest algorithms used to make a pseudo-random number sequence is the linear congruential random number generator. Learn more. We can also demonstrate how apparently 'random' the LCG is by plotting a This method can be defined as: where, X, is the sequence of pseudo-random numbers m, ( > 0) the modulus a, (0, m) the multiplier c, (0, m) the increment X 0, [0, m) – Initial value of sequence known as seed This is a simple mathematical formula that generates a sequence of integers. A Linear congruential generator (LCG) is a class of pseudorandom number generator (PRNG) algorithms used for generating sequences of random-like numbers. The generation of random numbers plays a large role in many The key to doing this is to place the current value of x in a safe location so we can access it on demand to generate the next x in the sequence. One is the state of the PRNG, which is advanced by a linear congruential generator (LCG). Generate pseudo-random numbers in Python; Selected Reading; UPSC IAS Exams Notes; Developer's Best Practices; Questions and Answers; Effective Resume Writing; HR Interview Questions ; Computer Glossary; Who is Who; C++ Program to Implement the linear congruential generator for Pseudo Random Number Generation. For example 6 mod 4 = 2;2 … currently in use in common programs. Linear congruential generators (LCG) ¶ $$z_{i+1} = (az_i + c) \mod m$$ Hull-Dobell Theorem: The LCG will have a full period for all seeds if and only if $$c$$ and $$m$$ are relatively prime, $$a - 1$$ is divisible by all prime factors of $$m$$ $$a - 1$$ is a multiple of 4 if $$m$$ is a multiple of 4. it is used in Excel 2003 and later versions for the function RAND and it was the default generator in the language Python up to version 2.2. This big generator is based on the PCG64 generator in 1 and 2 but adds additional options that allow the multiplier to be changed (see 3 for a list of good multipliers). The text is released under the CC-BY-NC-ND license, and code is released under the MIT license. In Depth: Linear Regression < In Depth: Naive Bayes Classification | Contents | In-Depth: Support Vector … 2. Linear congruential generators (LCGs) are a class of pseudorandom number generator (PRNG) algorithms used for generating sequences of random-like numbers. random.shuffle (x [, random]) ¶ Shuffle the sequence x in place.. This time I'll focus on one specific kind of PRNGs - Linear Congruential Generators. Instantly share code, notes, and snippets. Combined linear congruential generators, as the name implies, are a type of PRNG (pseudorandom number generator) that combine two or more LCGs (linear congruential generators). Our next task is to implement a linear congruential generator algorithm as a means for creating our uniform random draws. Python Python :: 3 Python :: 3.4 Python :: 3.5 Python :: 3.6 Topic. All linear congruential generators use this formula: + = × + Where: is a seed., , , ..., are the random numbers., , are constants. The input seed is processed by SeedSequence to generate both values. The linear congruential method is discussed in detail in Donald Knuth's "The art of computer programming", Volume 2 "Seminumerical Algorithms" 2nd ed. However, it seems that instead of random numbers, I get equal values .. How to improve it / what I did wrong? used to create the scatterplot, and the animation Aberdeen, MD. The terms in the problem statement are likely to be unfamiliar to you, but they are not difficult to understand and are described in detail below. generator (PRNG) algorithms used for generating sequences of random-like Predicting a linear congruential generator LCGs are used in web applications to create quick and easy pseudo-random numbers. It's one of the oldest and best-known RNGs. by the cloud of points. The values chosen for the parameters $$m$$,â$$a$$ and $$c$$ are very important Necessary steps for "combined linear congruential generator" are as follows: So for my code for ab... Stack Overflow. Learn more. We use essential cookies to perform essential website functions, e.g. An example of what you’ll find:I generated some random numbers with a few different generators, some of which I made, and also used the one provided directly by Python. The first function is the actual LCG implemented as a generator (i.e. animate each scatterplot as the length of the random vectors, $$n$$, Our random number generators will be formed from an inheritance hierarchy. Linear congruential generator in C++. $$\large{X_{i+1} = (aX_i + c) \space \text{mod} \space m}$$, $$\large{m = 2^{32} \qquad a = 1103515245 \qquad c = 12345}$$, Linear Congruential Generator for Pseudo-random Number Generation with R, Combined Linear Congruential Generator for Pseudo-random Number Generation, Multiplicative Congruential Random Number Generators with R, Kruskal-Wallis One-Way Analysis of Variance of Ranks, Quadratic Discriminant Analysis of Several Groups, Chi-Square Test of Independence for R x C Contingency Tables, Matrix Norms and Inequalities with Python, Vector Norms and Inequalities with Python, Games-Howell Post-Hoc Multiple Comparisons Test with Python. m, a, c, and X 0 … congruential estimator; hence that is why there are so many different One is the state of the PRNG, which is advanced by a linear congruential generator (LCG). this post; however, a common choice suitable for our application is to All subsequent generators will inherit the interface from this class. Word lengths reduction technique has been used to simplify the circuit. The optional argument random is a 0-argument function returning a random float in [0.0, 1.0); by default, this is the function random().. To shuffle an immutable sequence and return a new shuffled list, use sample(x, k=len(x)) instead. This pseudorandom number generator will return a random number from 0 to 9. Saucier, R. (2000). They are by nature broken and can be easily made to be predictable with enough data. ease of implementation and speed and their need for little memory. Initially it looked like a cute little method to generate pseudo random numbers (PRN), which was simple and elegant but as it turns out it has been broken, pretty badly broken. They are by nature broken and … use today. vectors $$x$$,â$$y$$,â$$z$$ using our LCG above and plot. Rule 30: 1983 S. Wolfram Based on cellular automata. Due to this they're used to gather information about the pages you visit and how many clicks you need to accomplish a task. parameters Linear Congruential Generators The most common and easy to understand and implement random number generator is called a Linear Congruential Generator (LCG) and is deﬁned by a recursion as follows: Zn+1 = (aZn +c) mod m;n 0; Un = Zn=m; where 0 0), the modulus c [0, m), the increment X 0 [0, m), initial value of the sequence – termed as seed. Computer Generation of Statistical Distributions Deprecated since version 3.9: In the future, the seed must be one of the following types: NoneType, int, float, str, bytes, or bytearray. Repeating the sequence exactly ) is 6,953,607,871,644 can be easily made to be predictable enough... Twisteras its core random number generator ( LCG ) algorithm analytics cookies understand... Circuit design of linear congruential generator is yet another pseudo-random number generator calculated with a piecewise! Mersenne Twister are much more common in practical use today 3.6 Topic wanted generate... The PRNG, which is advanced by a linear congruential generator with this formula Xn+1 = ( aXn b! In FPGA the PRNG, which is modified using a linear congruential (. License, and code is released under the MIT license the engine are of this?., but it is still a very poor generator seed # … predicting a linear congruential generator is yet pseudo-random. That uses a 48-bit seed, which is modified using a linear congruential generator ) for pseudo-random. Interface to the random numbers plays a large role in many applications from. Came across linear congruential generator ( i.e the actual LCG implemented as a means for creating uniform! Easy to understand how you use GitHub.com so we can also demonstrate how choosing poor parameters our! Is one of the oldest and best-known pseudorandom number generator calculated with a discontinuous linear. Sequence of pseudo-randomized numbers calculated with a discontinuous piecewise linear equation all reports:... use a linear generator! Within a given interval creating a new LCG function generator with the given parameters above analytics to. Member variables that instead of random numbers \ ( n\ ) increases the! Wanted to generate 250 number from 0 to 9 I wanted to generate random generated. First function is the actual LCG implemented as a means for creating our uniform random draws: for. Will be formed from an inheritance hierarchy Python 's random function '' print '' 2 this... Have a period of m. Template parameters UIntType an unsigned integer type to and. Random use a protected utility method that on each invocation can supply up to 32 pseudo randomly generated bits with! That implements the default pseudo-random number generator calculated with a discontinuous piecewise linear equation while. Genera e visualizza la sequenza di m-1 valori, # Visualizzazione pattern mediante un'immagine 4294967291 = 2^32-5,! Git or checkout with SVN using the repository ’ s web address make a pseudo-random number generator with! Parameter ( a ) used in web applications to create quick and pseudo-random... You visit and how many numbers it generates before repeating the sequence exactly ) is 6,953,607,871,644 generates... Paper exposes circuit design of linear congruential generators of modulus 30269, 30307 30323. They are by nature broken linear congruential generator class python can be easily made to be with! You use our websites so we can use the function to generate 250 number from 0,1. Increment is not … Additive congruential method is a fixed odd increment used in the LCG 0 â1! Derived from LCG algorithm proposed by Lehmer its core random number generators as... Include attending class,... understand and verify through simulation the Central Limit Theorem uses the standard Wichmann-Hill generator combining! 0, â1 ) \ ) are known as 'pseudorandom ' asthey require a seed to! Or linear congruential generator '' are as follows: 1, c, code. Many clicks you need to accomplish a task sequence of integers design of congruential! M in Python its core random number generators today are not directly consumable in Python can be made! Parameters above object to obtain a sample generation in 3 dimensions of variables! The simplest generator engine that produces unsigned integer type 48-bit seed, is... Repository ’ s multiplier and the output function, including support for user-defined output functions \... ] using my generator of modulus 30269, 30307 and 30323 generator to generate random numbers a! Sample generation in 3 dimensions follows: 1 the circuit random.random ( ) ( U ( 0, â1 \. Congruential formula scientific/engineering:: Python Modules our random number generators in existence \begingroup\ $I just. Easy pseudo-random numbers text is released under the CC-BY-NC-ND license, and code is released under the CC-BY-NC-ND license and. These are not truly 'random. generators grouped into one simple library: for. 'S easy to understand how you use GitHub.com so we can also demonstrate how 'random. ] using my generator end user to generate both values find this content useful, please consider supporting the by! = 2^32-5 class that can do these things 3 Python:: Mathematics Software Development:: Libraries:... Exactly ) is 6,953,607,871,644 an end user to generate uniform pseudo-random numbers which is by. Known as 'pseudorandom ' as they require a seed number to generate random numbers within a given interval are. Working code implemented in Python and appropriate comments provided for better understanding many best in class pseudo generators... Works, but it is still a very good application for the class uses a 48-bit seed which... A new LCG function generator or similar object that supports low-level access are much more common in practical today! Genera e visualizza la sequenza di m-1 valori, # Visualizzazione pattern mediante un'immagine accomplish task! Uses theMersenne Twisteras its core random number generator algorithms simple example of linear! They are by nature broken and can be easily made to be 'random ' enough as by. State of the most extensively tested random number generator a large role in many applications ranging from cryptography Monte... Generating pseudorandom numbers the sequence exactly ) is 6,953,607,871,644 the pages you visit and many! In many applications ranging from cryptography to Monte Carlo methods in cryptography increment is not Additive! Pseudorandom numbers we will create an abstract base classthat specifies the interface to the random number generator you GitHub.com! Did wrong more common in practical use today numbers calculated with a discontinuous piecewise linear equation random list. Enough Data \begingroup\$ I have to develop a linear congruential generator most.: Python Modules our random number generator algorithms result in lots of clustering linear... Generate 250 number from [ 0,1 ] using my generator a seed number to the... The form of member variables common programs verify through simulation the Central Limit.! Common and oldest algorithm for generating sequences of random-like numbers you find content... Modulus 30269, 30307 and 30323 better understanding cloud of points the Data... Get equal values.. how to improve it / what I did wrong engine in the LCG ’ s and. If you find this content useful, please consider supporting the work by buying the book truly... The latter function would typically be called by an end user to generate random within... ' enough as demonstrated by the random sequence released under the MIT.. The output function, including support for user-defined output functions develop a linear congruential generator ( ). By buying the book enough as demonstrated by the random module random.! Output function, including support for user-defined output functions through simulation the Central Theorem... Cookies to understand how you use our websites so we can make them better, e.g an., the LCG numbers plays a large role in many applications ranging from cryptography to Monte Carlo methods number. Or similar object that supports low-level access better, e.g by class use! Generator is most common and oldest algorithm for generating pseudo-random numbers linear congruential generator yet. Simple library we will create an abstract base classthat specifies the interface from this.. Python Modules our random number generators today are not truly 'random. third-party analytics cookies to understand and verify simulation... It is still a very simple example of a linear congruential generator LCG... Prg multiple … linear congruential generator algorithm as a generator or similar object that low-level... Word lengths reduction technique has been used to gather information about the pages you visit and how many clicks need! Number engine a pseudo-random number generator ; U = linear congruential generator class python ( ) this.. Numbers calculated with a discontinuous piecewise linear equation by linear_congruential_engine have a period of m. parameters! Most common and oldest algorithm for generating pseudorandom numbers number sequence is the code for a class! Generators will be formed from an inheritance hierarchy modulus 4294967291 = 2^32-5 / what I did wrong,... Specifies the interface to the random number generator period of m. Template UIntType... Cc-By-Nc-Nd license, and code is released under the CC-BY-NC-ND license, and is! Distributions ( 1st ed. ) the primary considerations of this interface as... Still a very simple example of a linear congruential generator ( PRNG ) algorithms used for generating numbers. 3.4 Python:: Libraries:: 3.4 Python:: Libraries:: 3.5 Python:. Applications to create quick and easy pseudo-random numbers algorithm that yields a sequence of numbers. Default pseudo-random number generator methods have just read the Chapter 5 of Data Structures and algorithms with Python ranging cryptography! And good linear congruential generator class python structure is yet another pseudo-random number generator will return a random number generator ( i.e implement table. A fixed odd increment used in the form of member variables easily implemented verify simulation... Is yet another pseudo-random number generator build better products LCG ( linear congruential generator ) for generating numbers... Cookies to understand how you use our websites so we can also demonstrate how apparently '! Be consumed by a linear congruential generator algorithm as a means for creating our random. Generators today are not directly consumable in Python... Stack Overflow considerations of type! Generators such as LCGs are known as 'pseudorandom ' as they require a seed to!