# random-mtzig
The `random-mtzig` library is a Chicken Scheme wrapper for the MT19937
random number generator used in GNU Octave
(http://www.gnu.org/software/octave/).
## Procedures
init :: [SEED] -> STATE
Creates an initial seed array and returns the corresponding generator
state vector. If the optional `SEED` is not specified, the generator
is initialized with a seed from `/dev/urandom` or with the current
time in seconds. If `SEED` can be an integer or an `u32vector`.
random! :: STATE -> INTEGER
Returns a random integer value between 0 and the largest
machine-representable unsigned integer on the current platform.
randu! :: STATE -> NUMBER
Returns a random value from a uniform distribution on the interval
`(0, 1)`.
randn! :: STATE -> NUMBER
Returns a random value from a normal (Gaussian) distribution, using
Marsaglia and Tsang's Ziggurat algorithm to transform a uniform
distribution into a normal one.
rande! :: STATE -> NUMBER
Returns a random value from an exponential distribution, using
Marsaglia and Tsang's Ziggurat algorithm to transform a uniform
distribution into an exponential one.
randb! :: N * P * STATE -> NUMBER
Returns a random value from a binomial distribution with `N`
experiments and probability `P`.
randp! :: L * STATE -> NUMBER
Returns a random value from a Poisson distribution with mean value `L`.
f64vector-randu! :: N * STATE -> F64VECTOR
Returns an SRFI-4 `f64` vector of random values from a uniform
distribution on the interval `(0, 1)`.
f64vector-randn! :: N * STATE -> F64VECTOR
Returns an SRFI-4 `f64` vector of random values from a normal
(Gaussian) distribution, using Marsaglia and Tsang's Ziggurat
algorithm to transform a uniform distribution into a normal one.
f64vector-rande! :: N * STATE -> F64VECTOR
Returns an SRFI-4 `f64` vector of random values from am exponential
distribution, using Marsaglia and Tsang's Ziggurat algorithm to
transform a uniform distribution into an exponential one.
f64vector-randb! :: N * P * XN * STATE -> F64VECTOR
Returns an SRFI-4 `f64` vector of random values from a binomial
distribution with `N` experiments and probability `P`.
f64vector-randp! :: L * XN * STATE -> F64VECTOR
Returns an SRFI-4 `f64` vector of random values from a Poisson
distribution with mean value `L`.
f32vector-randu! :: N * STATE -> F32VECTOR
Returns an SRFI-4 `f32` vector of random values from a uniform
distribution on the interval `(0, 1)`.
f32vector-randn! :: N * STATE -> F32VECTOR
Returns an SRFI-4 `f32` vector of random values from a normal
(Gaussian) distribution, using Marsaglia and Tsang's Ziggurat
algorithm to transform a uniform distribution into a normal one.
f32vector-rande! :: N * STATE -> F32VECTOR
Returns an SRFI-4 `f32` vector of random values from am exponential
distribution, using Marsaglia and Tsang's Ziggurat algorithm to
transform a uniform distribution into an exponential one.
f32vector-randb! :: N * P * XN * STATE -> F32VECTOR
Returns an SRFI-4 `f32` vector of random values from a binomial
distribution with `N` experiments and probability `P`.
f32vector-randb! :: L * XN * STATE -> F32VECTOR
Returns an SRFI-4 `f32` vector of random values from a Poisson
distribution with mean value `L`.
## Examples
```scheme
(require-extension random-mtzig)
(define st (init 24))
(f64vector-randu! 20 st)
```
## License
```
Chicken Scheme egg scripts and documentation Copyright 2007-2015 Ivan Raikov.
Coded by Takuji Nishimura and Makoto Matsumoto.
This is a faster version by taking Shawn Cokus's optimization,
Matthe Bellew's simplification, Isaku Wada's real version.
David Bateman added normal and exponential distributions following
Marsaglia and Tang's Ziggurat algorithm.
Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
Copyright (C) 2004, David Bateman
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The names of its contributors may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
```