@(@\newcommand{\W}[1]{ \; #1 \; }
\newcommand{\R}[1]{ {\rm #1} }
\newcommand{\B}[1]{ {\bf #1} }
\newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} }
\newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} }
\newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} }
\newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }@)@This is cppad-20221105 documentation. Here is a link to its
current documentation
.
Using base2ad and VecAD together: Example and Test
Purpose
This example demonstrate that base2ad
does not convert
VecAD
operations as might be expected.
To be specific, this indexing into a VecAD object gets fixed
when zero order forward mode is run for a base2ad result; e.g.
af
below.
# include <cppad/cppad.hpp>
bool base2vec_ad(void)
{ using CppAD::vector;
using CppAD::AD;
//
bool ok = true;
//// f(x) = x[0] if 0 <= x[2] < 1// = x[1] if 1 <= x[2] < 2
vector< AD<double> > ax(3), ay(1);
ax[0] = 3.0;
ax[1] = 2.0;
ax[2] = 1.0;
Independent(ax);
CppAD::VecAD<double> av(2);
av[ AD<double>(0) ] = ax[0];
av[ AD<double>(1) ] = ax[1];
ay[0] = av[ ax[2] ];
CppAD::ADFun<double> f(ax, ay);
//// ok// value during recording of f
ok &= ay[0] == ax[1];
//// ok// f zero order forward mode, the VecAD commands give expected result
vector<double> x(3), y(1);
x[0] = 2.0;
x[1] = 1.0;
x[2] = 0.0;
y = f.Forward(0, x);
ok &= y[0] == x[0];
//// af
CppAD::ADFun< AD<double>, double > af = f.base2ad();
//// g
ax[0] = 3.0;
ax[1] = 2.0;
ax[2] = 1.0;
Independent(ax);
ay = af.Forward(0, ax);
CppAD::ADFun<double> g(ax, ay);
//// ok// value during recording of g
ok &= ay[0] == ax[1];
//// ok// g zero order forward mode// Note that this index does not change, but the value does
x[0] = 5.0;
x[1] = 4.0;
x[2] = 0.0;
y = g.Forward(0, x);
ok &= y[0] == x[1];
//return ok;
}
