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2.8.0
reverse mode automatic differentiation
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stan
math
fwd
scal
fun
inv_sqrt.hpp
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#ifndef STAN_MATH_FWD_SCAL_FUN_INV_SQRT_HPP
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#define STAN_MATH_FWD_SCAL_FUN_INV_SQRT_HPP
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#include <
stan/math/fwd/core.hpp
>
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#include <boost/math/tools/promotion.hpp>
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namespace
stan {
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namespace
math {
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template
<
typename
T>
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inline
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fvar<T>
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inv_sqrt
(
const
fvar<T>
& x) {
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using
std::sqrt
;
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T sqrt_x(
sqrt
(x.
val_
));
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return
fvar<T>
(1 / sqrt_x, -0.5 * x.
d_
/ (x.
val_
* sqrt_x));
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}
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}
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}
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#endif
core.hpp
stan::math::inv_sqrt
fvar< T > inv_sqrt(const fvar< T > &x)
Definition:
inv_sqrt.hpp:15
stan::math::fvar::d_
T d_
Definition:
fvar.hpp:15
stan::math::sqrt
fvar< T > sqrt(const fvar< T > &x)
Definition:
sqrt.hpp:15
stan::math::fvar::val_
T val_
Definition:
fvar.hpp:14
stan::math::fvar
Definition:
fvar.hpp:13
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