1 #ifndef STAN_MATH_REV_SCAL_FUN_ACOS_HPP
2 #define STAN_MATH_REV_SCAL_FUN_ACOS_HPP
12 class acos_vari :
public op_v_vari {
14 explicit acos_vari(vari* avi) :
15 op_v_vari(
std::
acos(avi->val_), avi) {
18 avi_->adj_ -= adj_ /
std::sqrt(1.0 - (avi_->val_ * avi_->val_));
60 return var(
new acos_vari(a.
vi_));
fvar< T > sqrt(const fvar< T > &x)
Independent (input) and dependent (output) variables for gradients.
vari * vi_
Pointer to the implementation of this variable.
fvar< T > acos(const fvar< T > &x)