pynbody.util.bisect

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pynbody.util.bisect#

pynbody.util.bisect(left, right, f, epsilon=None, eta=0, niter_max=200)[source]#

Finds the value x such that f(x)=0 for a monotonically increasing function f, using a binary search.

The search stops when either the bounding domain is smaller than epsilon (by default 10^-7 times the original region) OR a value f(x) is found such that |f(x)|<eta (by default eta=0, so this criterion is never satisfied).

Parameters:

  • left (float) – The left-hand boundary of the search region

  • right (float) – The right-hand boundary of the search region

  • f (function) – The function to find the root of

  • epsilon (float, optional) – The tolerance for the search. If not specified, this is set to 10^-7 times the original region.

  • eta (float, optional) – The tolerance for the function value. If a value f(x) is found such that |f(x)|<eta, the search stops.

  • niter_max (int, optional) – The maximum number of iterations to perform. If the search does not converge after this, a ValueError is raised.

Returns:

The value x such that f(x)=0

Return type:

float

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