The Logistic class.
This class represents the elementwise operation \log(1 + e^x). This is a special case of log(sum(exp)) that evaluates to a vector rather than to a scalar, which is useful for logistic regression.
Logistic(x) ## S4 method for signature 'Logistic' to_numeric(object, values) ## S4 method for signature 'Logistic' sign_from_args(object) ## S4 method for signature 'Logistic' is_atom_convex(object) ## S4 method for signature 'Logistic' is_atom_concave(object) ## S4 method for signature 'Logistic' is_incr(object, idx) ## S4 method for signature 'Logistic' is_decr(object, idx) ## S4 method for signature 'Logistic' .grad(object, values)
x |
An Expression or numeric constant. |
object |
A Logistic object. |
values |
A list of numeric values for the arguments |
idx |
An index into the atom. |
to_numeric
: Evaluates e^x
elementwise, adds one, and takes the natural logarithm.
sign_from_args
: The atom is positive.
is_atom_convex
: The atom is convex.
is_atom_concave
: The atom is not concave.
is_incr
: The atom is weakly increasing.
is_decr
: The atom is not weakly decreasing.
.grad
: Gives the (sub/super)gradient of the atom w.r.t. each variable
x
An Expression or numeric constant.
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