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# include <cstddef> // define size_t
# include <cmath> // for fabs function
extern bool exp_eps_for0(double *v0); // computes zero order forward sweep
bool exp_eps_rev1(void)
{ bool ok = true;
// set the value of v0[j] for j = 1 , ... , 7
double v0[8];
ok &= exp_eps_for0(v0);
// initial all partial derivatives as zero
double f_v[8];
size_t j;
for(j = 0; j < 8; j++)
f_v[j] = 0.;
// set partial derivative for f7
f_v[7] = 1.;
ok &= std::fabs( f_v[7] - 1. ) <= 1e-10; // f7_v7
// f6( v1 , v2 , v3 , v4 , v5 , v6 )
f_v[4] += f_v[7] * 1.;
f_v[6] += f_v[7] * 1.;
ok &= std::fabs( f_v[4] - 1. ) <= 1e-10; // f6_v4
ok &= std::fabs( f_v[6] - 1. ) <= 1e-10; // f6_v6
// f5( v1 , v2 , v3 , v4 , v5 )
f_v[5] += f_v[6] / 2.;
ok &= std::fabs( f_v[5] - 0.5 ) <= 1e-10; // f5_v5
// f4( v1 , v2 , v3 , v4 )
f_v[1] += f_v[5] * v0[3];
f_v[3] += f_v[5] * v0[1];
ok &= std::fabs( f_v[1] - 0.25) <= 1e-10; // f4_v1
ok &= std::fabs( f_v[3] - 0.25) <= 1e-10; // f4_v3
// f3( v1 , v2 , v3 )
f_v[3] += f_v[4] * 1.;
ok &= std::fabs( f_v[3] - 1.25) <= 1e-10; // f3_v3
// f2( v1 , v2 )
f_v[2] += f_v[3] / 1.;
ok &= std::fabs( f_v[2] - 1.25) <= 1e-10; // f2_v2
// f1( v1 )
f_v[1] += f_v[2] * 1.;
ok &= std::fabs( f_v[1] - 1.5 ) <= 1e-10; // f1_v2
return ok;
}