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  2. Entropy (information theory) - Wikipedia

    en.wikipedia.org/wiki/Entropy_(information_theory)

    In this form the relative entropy generalizes (up to change in sign) both the discrete entropy, where the measure m is the counting measure, and the differential entropy, where the measure m is the Lebesgue measure. If the measure m is itself a probability distribution, the relative entropy is non-negative, and zero if p = m as measures.

  3. Softmax function - Wikipedia

    en.wikipedia.org/wiki/Softmax_function

    In statistical mechanics, the softargmax function is known as the Boltzmann distribution (or Gibbs distribution): [5]: 7 the index set , …, are the microstates of the system; the inputs are the energies of that state; the denominator is known as the partition function, often denoted by Z; and the factor β is called the coldness (or ...

  4. Multinomial logistic regression - Wikipedia

    en.wikipedia.org/wiki/Multinomial_logistic...

    Multinomial logistic regression is known by a variety of other names, including polytomous LR, [2] [3] multiclass LR, softmax regression, multinomial logit (mlogit), the maximum entropy (MaxEnt) classifier, and the conditional maximum entropy model.

  5. Void coefficient - Wikipedia

    en.wikipedia.org/wiki/Void_coefficient

    A positive void coefficient means that the reactivity increases as the void content inside the reactor increases due to increased boiling or loss of coolant; for example, if the coolant acts predominantly as neutron absorber. This positive void coefficient causes a positive feedback loop, starting with the first occurrence of steam bubbles ...

  6. Cross-entropy - Wikipedia

    en.wikipedia.org/wiki/Cross-entropy

    In information theory, the cross-entropy between two probability distributions and , over the same underlying set of events, measures the average number of bits needed to identify an event drawn from the set when the coding scheme used for the set is optimized for an estimated probability distribution , rather than the true distribution .

  7. Loss functions for classification - Wikipedia

    en.wikipedia.org/wiki/Loss_functions_for...

    It's easy to check that the logistic loss and binary cross-entropy loss (Log loss) are in fact the same (up to a multiplicative constant ⁡ ()). The cross-entropy loss is closely related to the Kullback–Leibler divergence between the empirical distribution and the predicted distribution.

  8. Mutual information - Wikipedia

    en.wikipedia.org/wiki/Mutual_information

    The joint information is equal to the mutual information plus the sum of all the marginal information (negative of the marginal entropies) for each particle coordinate. Boltzmann's assumption amounts to ignoring the mutual information in the calculation of entropy, which yields the thermodynamic entropy (divided by the Boltzmann constant).

  9. Entropy coding - Wikipedia

    en.wikipedia.org/wiki/Entropy_coding

    In information theory, an entropy coding (or entropy encoding) is any lossless data compression method that attempts to approach the lower bound declared by Shannon's source coding theorem, which states that any lossless data compression method must have an expected code length greater than or equal to the entropy of the source. [1]