| 21 | struct tape_size { size_t n_var; size_t n_op; }; |
| 22 | |
| 23 | template <class Vector> void fun( |
| 24 | const Vector& x, Vector& y, tape_size& before, tape_size& after |
| 25 | ) |
| 26 | { typedef typename Vector::value_type scalar; |
| 27 | |
| 28 | // phantom variable with index 0 and independent variables |
| 29 | // begin operator, independent variable operators and end operator |
| 30 | before.n_var = 1 + x.size(); before.n_op = 2 + x.size(); |
| 31 | after.n_var = 1 + x.size(); after.n_op = 2 + x.size(); |
| 32 | |
| 33 | // initialized product of even and odd variables |
| 34 | scalar prod_even = x[0]; |
| 35 | scalar prod_odd = x[1]; |
| 36 | before.n_var += 0; before.n_op += 0; |
| 37 | after.n_var += 0; after.n_op += 0; |
| 38 | // |
| 39 | // compute product of even and odd variables |
| 40 | for(size_t i = 2; i < size_t( x.size() ); i++) |
| 41 | { if( i % 2 == 0 ) |
| 42 | { // prod_even will affect dependent variable |
| 43 | prod_even = prod_even * x[i]; |
| 44 | before.n_var += 1; before.n_op += 1; |
| 45 | after.n_var += 1; after.n_op += 1; |
| 46 | } |
| 47 | else |
| 48 | { // prod_odd will not affect dependent variable |
| 49 | prod_odd = prod_odd * x[i]; |
| 50 | before.n_var += 1; before.n_op += 1; |
| 51 | after.n_var += 0; after.n_op += 0; |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | // dependent variable for this operation sequence |
| 56 | y[0] = prod_even; |
| 57 | before.n_var += 0; before.n_op += 0; |
| 58 | after.n_var += 0; after.n_op += 0; |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | bool reverse_active(void) |