elephant.kernels.AlphaKernel¶
-
class
elephant.kernels.
AlphaKernel
(sigma, invert=False)[source]¶ Class for alpha kernels.
with .
For the alpha kernel an analytical expression for the boundary of the integral as a function of the area under the alpha kernel function cannot be given. Hence in this case the value of the boundary is determined by kernel-approximating numerical integration, inherited from the Kernel class.
Attributes: min_cutoff
floatHalf width of the kernel.
-
__call__
(self, t)¶ Evaluates the kernel at all points in the array t.
Parameters: - tpq.Quantity
Vector with the interval on which the kernel is evaluated, not necessarily a time interval.
Returns: - pq.Quantity
Vector with the result of the kernel evaluations.
Raises: - TypeError
If t is not pq.Quantity.
If the dimensionality of t and
sigma
are different.
-
boundary_enclosing_area_fraction
(self, fraction)¶ Calculates the boundary so that the integral from to encloses a certain fraction of the integral over the complete kernel.
By definition the returned value is hence non-negative, even if the whole probability mass of the kernel is concentrated over negative support for inverted kernels.
Returns: - pq.Quantity
Boundary of the kernel containing area fraction under the kernel density.
Raises: - ValueError
If fraction was chosen too close to one, such that in combination with integral approximation errors the calculation of a boundary was not possible.
-
is_symmetric
(self)¶ In the case of symmetric kernels, this method is overwritten in the class SymmetricKernel, where it returns True, hence leaving the here returned value False for the asymmetric kernels.
Returns: - bool
True in classes SymmetricKernel, RectangularKernel, TriangularKernel, EpanechnikovLikeKernel, GaussianKernel, and LaplacianKernel. False in classes Kernel, ExponentialKernel, and AlphaKernel.
-
property
min_cutoff
¶ Half width of the kernel.
Returns: - float
The returned value varies according to the kernel type.