mt.geond.moments

Raw moments up to 2nd order of ND points.

Functions

mt.geond.moments.moments_from_pointlist(pl)

Constructs a Moments object from a list of points.

Parameters:

pl (PointList) – list of points from which the moments are computed

Returns:

raw moments of the point list, depending on the value of ndim provided

Return type:

Moments, Moments2d or Moments3d

Classes

  • Moments: Raw moments up to 2nd order of points living in the same Euclidean space.

class mt.geond.moments.Moments(m0, m1, m2)

Raw moments up to 2nd order of points living in the same Euclidean space.

Overloaded operators are negation, multiplication with a scalar and true division with a scalar.

Parameters:

  • m0 (scalar) – 0th-order raw moment

  • m1 (numpy 1d array of length D, where D is the ndim of the class) – 1st-order raw moment

  • m2 (numpy DxD matrix) – 2nd-order raw moment

Examples

>>> import mt.geo2d.polygon as gp
>>> poly = gp.Polygon([[0,0],[0,1],[1,2],[1,0]])
>>> import mt.geond.moments as gm
>>> from mt.base.casting import cast
>>> m = cast(poly, gm.Moments2d)
>>> m.m0
4.0
>>> m.m1
array([2, 3])
>>> m.m2
array([[2, 2],
       [2, 5]])
>>> m.mean
array([0.5 , 0.75])
>>> m.cov
array([[0.25  , 0.125 ],
       [0.125 , 0.6875]])

Inheritance

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__init__(m0, m1, m2)
__mul__(scalar)

Returns a new instance where all the moments are multiplied by a scalar.

__neg__()

Returns a new instance where all the moments are negated.

__repr__()

Return repr(self).

__truediv__(scalar)

Returns a new instance where all the moments are divided by a scalar.

property cov

Returns the covariance matrix.

property m0

0th-order moment

property m1

1st-order moment

property m2

2nd-order moment

property mean

Returns the mean vector.

property ndim

Returns the number of dimensions in which the geometric object lives.

Variables

mt.geond.moments.EPSILON

Double-precision floating-point number type, compatible with Python float and C double.

Character code:

'd'

Canonical name:

numpy.double

Alias:

numpy.float_

Alias on this platform (Linux x86_64):

numpy.float64: 64-bit precision floating-point number type: sign bit, 11 bits exponent, 52 bits mantissa.

1.4901161193847656e-08