galois.GFp

class galois.GFp(*args, **kwargs)[source]

Bases: galois.gf.GF, galois.gf.GFArray

An abstract base class for all \(\mathrm{GF}(p)\) field array classes.

Parameters

  • array (array_like) – The input array to be converted to a Galois field array. The input array is copied, so the original array is unmodified by changes to the Galois field array. Valid input array types are numpy.ndarray, list, tuple, or int.

  • dtype (numpy.dtype, optional) – The numpy.dtype of the array elements. The default is numpy.int64.

Returns

The copied input array as a \(\mathrm{GF}(p)\) field array.

Return type

galois.GFp

Note

This is an abstract base class for all \(\mathrm{GF}(p)\) fields. It cannot be instantiated directly. \(\mathrm{GF}(p)\) field classes are created using galois.GF_factory.

classmethod Elements(dtype=None)

Create a Galois field array of the field’s elements \(\{0, \dots, p^m-1\}\).

Parameters

dtype (numpy.dtype, optional) – The numpy.dtype of the array elements. The default is None which represents the smallest valid dtype for this field class, i.e. cls.dtypes[0].

classmethod Ones(shape, dtype=None)

Create a Galois field array with all ones.

Parameters

  • shape (tuple) – A numpy-compliant shape tuple, see numpy.ndarray.shape. An empty tuple () represents a scalar. A single integer or 1-tuple, e.g. N or (N,), represents the size of a 1-dim array. An n-tuple, e.g. (M,N), represents an n-dim array with each element indicating the size in each dimension.

  • dtype (numpy.dtype, optional) – The numpy.dtype of the array elements. The default is None which represents the smallest valid dtype for this field class, i.e. cls.dtypes[0].

classmethod Random(shape=(), low=0, high=None, dtype=None)

Create a Galois field array with random field elements.

Parameters

  • shape (tuple) – A numpy-compliant shape tuple, see numpy.ndarray.shape. An empty tuple () represents a scalar. A single integer or 1-tuple, e.g. N or (N,), represents the size of a 1-dim array. An n-tuple, e.g. (M,N), represents an n-dim array with each element indicating the size in each dimension.

  • low (int, optional) – The lowest value (inclusive) of a random field element. The default is 0.

  • high (int, optional) – The highest value (exclusive) of a random field element. The default is None which represents the field’s order \(p^m\).

  • dtype (numpy.dtype, optional) – The numpy.dtype of the array elements. The default is None which represents the smallest valid dtype for this field class, i.e. cls.dtypes[0].

classmethod Zeros(shape, dtype=None)

Create a Galois field array with all zeros.

Parameters

  • shape (tuple) – A numpy-compliant shape tuple, see numpy.ndarray.shape. An empty tuple () represents a scalar. A single integer or 1-tuple, e.g. N or (N,), represents the size of a 1-dim array. An n-tuple, e.g. (M,N), represents an n-dim array with each element indicating the size in each dimension.

  • dtype (numpy.dtype, optional) – The numpy.dtype of the array elements. The default is None which represents the smallest valid dtype for this field class, i.e. cls.dtypes[0].

classmethod display(mode='int', poly_var='x')

Sets the printing mode for arrays.

Parameters

  • mode (str, optional) – The field element display mode, either "int" (default) or "poly".

  • poly_var (str, optional) – The polynomial representation’s variable. The default is "x".

Examples

In [1]: GF = galois.GF_factory(2, 3)

In [2]: a = GF.Random(4); a
Out[2]: GF([3, 1, 1, 3], order=2^3)

In [3]: GF.display("poly"); a
Out[3]: GF([x + 1, 1, 1, x + 1], order=2^3)

In [4]: GF.display("poly", "r"); a
Out[4]: GF([r + 1, 1, 1, r + 1], order=2^3)

# Reset the print mode
In [5]: GF.display(); a
Out[5]: GF([3, 1, 1, 3], order=2^3)
classmethod target(target, mode, rebuild=False)[source]

Retarget the just-in-time compiled numba ufuncs.

Parameters

  • target (str) – The target keyword argument from numba.vectorize, either "cpu", "parallel", or "cuda".

  • mode (str) – The type of field computation, either "lookup" or "calculate". The “lookup” mode will use Zech log, log, and anti-log lookup tables for speed. The “calculate” mode will not store any lookup tables, but perform field arithmetic on the fly. The “calculate” mode is designed for large fields that cannot store lookup tables in RAM. Generally, “calculate” will be slower than “lookup”.

  • rebuild (bool, optional) – Indicates whether to force a rebuild of the lookup tables. The default is False.

alpha = None

The primitive element of the Galois field \(\mathrm{GF}(p^m)\). The primitive element is a root of the primitive polynomial \(p(x)\), such that \(p(\alpha) = 0\). The primitive element is also a multiplicative generator of the field, such that \(\mathrm{GF}(p^m) = \{0, 1, \alpha^1, \alpha^2, \dots, \alpha^{p^m - 2}\}\).

Type

int

characteristic = None

The prime characteristic \(p\) of the Galois field \(\mathrm{GF}(p^m)\). Adding \(p\) copies of any element will always result in \(0\).

Type

int

degree = None

The prime characteristic’s degree \(m\) of the Galois field \(\mathrm{GF}(p^m)\). The degree is a positive integer.

Type

int

dtypes = []

List of valid integer numpy.dtype objects that are compatible with this Galois field array class. Valid data types are signed and unsinged integers that can represent decimal values in \([0, p^m)\).

Type

list

order = None

The order \(p^m\) of the Galois field \(\mathrm{GF}(p^m)\). The order of the field is also equal to the field’s size.

Type

int

prim_poly = None

The primitive polynomial \(p(x)\) of the Galois field \(\mathrm{GF}(p^m)\). The primitive polynomial is of degree \(m\) in \(\mathrm{GF}(p)[x]\).

Type

galois.Poly

ufunc_mode = None

The mode for ufunc compilation, either "lookup" or "calculate".

Type

str

ufunc_target = None

The numba target for the JIT-compiled ufuncs, either "cpu", "parallel", or "cuda".

Type

str