Skip to main content
Donate to the Python Software Foundation or Purchase a PyCharm License to Benefit the PSF! Donate Now

# samplitude

Project description

CLI generation and plotting of random variables

## Generators

In addition to the standard range function, we support infinite generators

  • exponential(lambd): lambd is 1.0 divided by the desired mean.
  • uniform(a, b): Get a random number in the range [a, b) or [a, b] depending on rounding.
  • gauss(mu, sigma): mu is the mean, and sigma is the standard deviation.
  • normal(mu, sigma): as above
  • lognormal(mu, sigma): as above
  • triangular(low, high): Continuous distribution bounded by given lower and upper limits, and having a given mode value in-between.
  • beta(alpha, beta): Conditions on the parameters are alpha > 0 and beta > 0. Returned values range between 0 and 1.
  • gamma(alpha, beta): as above
  • weibull(alpha, beta): alpha is the scale parameter and beta is the shape parameter.
  • pareto(alpha): Pareto distribution. alpha is the shape parameter.
  • vonmises(mu, kappa): mu is the mean angle, expressed in radians between 0 and 2*pi, and kappa is the concentration parameter, which must be greater than or equal to zero. If kappa is equal to zero, this distribution reduces to a uniform random angle over the range 0 to 2*pi.

We have a special infinite generator (filter) that works on finite generators:

  • choice,

whose behaviour is explained below.

Finally, we have a generator

  • stdin()

that reads from stdin.

## A warning about infinity

All generators are infinite generators, and must be sampled with sample(n) before consuming!

## Usage and installation

Install with `bash pip install git+https://github.com/pgdr/samplitude ` or simply (not possible, though) `bash pip install samplitude `

### Examples

This is pure Jinja2: `bash >>> samplitude "range(5) | list" [0, 1, 2, 3, 4] `

However, to get a more UNIXy output, we use cli instead of list:

`bash >>> samplitude "range(5) | cli" 0 1 2 3 4 `

To limit the output, we use sample(n):

`bash >>> samplitude "range(1000) | sample(5) | cli" 0 1 2 3 4 `

That isn’t very helpful on the range generator, but is much more helpful on an infinite generator, such as the uniform generator:

`bash >>> samplitude "uniform(0, 5) | sample(5) | cli" 3.3900198868059235 1.2002767137709318 0.40999391897569126 1.9394585953696264 4.37327472704115 `

We can round the output in case we don’t need as many digits (note that round is a generator as well and can be placed on either side of sample): `bash >>> samplitude "uniform(0, 5) | round(2) | sample(5) | cli" 4.58 4.33 1.87 2.09 4.8 `

### Selection and modifications

The samplitude behavior is equivalent to the head program, or from languages such as Haskell. The head alias is supported: `bash >>> samplitude "uniform(0, 5) | round(2) | head(5) | cli" 4.58 4.33 1.87 2.09 4.8 `

drop is also available: `bash >>> samplitude "uniform(0, 5) | round(2) | drop(2) | head(3) | cli" 1.87 2.09 4.8 `

To shift and scale distributions, we can use the shift(s) and scale(s) filters. To get a Poisson point process starting at 15, we can run

`bash >>> samplitude "poisson(0.3) | shift(15)"  # equivalent to exponential(0.3)... `

### Choices and other operations

Using choice with a finite generator gives an infinite generator that chooses from the provided generator:

`bash >>> samplitude "range(0, 11, 2) | choice | sample(6) | cli" 8 0 8 10 4 6 `

Jinja2 supports more generic lists, e.g., lists of string. Hence, we can write

`bash >>> samplitude "['win', 'draw', 'loss'] | choice | sample(6) | sort | cli" draw draw draw loss win win `

… and as in Python, strings are also iterable:

`bash >>> samplitude "'HT' | cli" H T ` … so we can flip six coins with `bash >>> samplitude "'HT' | choice | sample(6) | cli" H T T H H H `

We can flip 100 coins and count the output with counter (which is collections.Counter) `bash >>> samplitude "'HT' | choice | sample(100) | counter | cli" H 47 T 53 `

The sort functionality does not work as expected on a Counter object (a dict type), so if we want the output sorted, we pipe through sort from _coreutils_:

`bash >>> samplitude "range(1,7) | choice | sample(100) | counter | cli" | sort -n 1 24 2 17 3 18 4 16 5 14 6 11 `

Using stdin() as a generator, we can pipe into samplitude. Beware that stdin() flushes the input, hence stdin (currently) does not work with infinite input streams.

`bash >>> ls | samplitude "stdin() | choice | sample(1) | cli" some_file `

Then, if we ever wanted to shuffle ls we can run

`bash >>> ls | samplitude "stdin() | shuffle | cli" some_file `

`bash >>> cat FILE | samplitude "stdin() | cli" # NOOP; cats FILE `

### The fun powder plot

For fun, if you have installed matplotlib, we support plotting, hist being the most useful.

`bash >>> samplitude "normal(100, 5) | sample(1000) | hist" `

![normal distribution](https://raw.githubusercontent.com/pgdr/samplitude/master/assets/hist_normal.png)

An exponential distribution can be plotted with exponential(lamba). Note that the cli output must be the last filter in the chain, as that is a command-line utility only:

`bash >>> samplitude "normal(100, 5) | sample(1000) | hist | cli" `

![exponential distribution](https://raw.githubusercontent.com/pgdr/samplitude/master/assets/hist_exponential.png)

To repress output after plotting, you can use the gobble filter to empty the pipe:

`bash >>> samplitude "normal(100, 5) | sample(1000) | hist | gobble" `

Home-page: https://github.com/pgdr/samplitude Author: PG Drange Author-email: pgdr@equinor.com Maintainer: PG Drange <pgdr@equinor.com> License: GNU GPL v3 or later Project-URL: Bug Tracker, https://github.com/pgdr/samplitude/issues Project-URL: Documentation, https://github.com/pgdr/samplitude/blob/master/README.md Project-URL: Source Code, https://github.com/pgdr/samplitude Description: UNKNOWN Keywords: jinja2 jinja random statistics sample distribution plot Platform: UNKNOWN

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
samplitude-0.0.2.tar.gz (5.4 kB) Copy SHA256 hash SHA256 Source None

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN SignalFx SignalFx Supporter DigiCert DigiCert EV certificate StatusPage StatusPage Status page