vdw_new.cpp
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1 #include <iostream>
2 #include <Eigen/Core>
3 
4 using namespace Eigen;
5 
6 #ifndef SCALAR
7 #define SCALAR float
8 #endif
9 
10 #ifndef SIZE
11 #define SIZE 10000
12 #endif
13 
14 #ifndef REPEAT
15 #define REPEAT 10000
16 #endif
17 
19 
20 using namespace std;
21 
22 SCALAR E_VDW(const Vec &interactions1, const Vec &interactions2)
23 {
24  return (interactions2.cwise()/interactions1)
25  .cwise().cube()
26  .cwise().square()
27  .cwise().square()
28  .sum();
29 }
30 
31 int main()
32 {
33  //
34  // 1 2 3 4 ... (interactions)
35  // ka . . . . ...
36  // rab . . . . ...
37  // energy . . . . ...
38  // ... ... ... ... ... ...
39  // (variables
40  // for
41  // interaction)
42  //
43  Vec interactions1(SIZE), interactions2(SIZE); // SIZE is the number of vdw interactions in our system
44  // SetupCalculations()
45  SCALAR rab = 1.0;
46  interactions1.setConstant(2.4);
47  interactions2.setConstant(rab);
48 
49  // Energy()
50  SCALAR energy = 0.0;
51  for (unsigned int i = 0; i<REPEAT; ++i) {
52  energy += E_VDW(interactions1, interactions2);
53  energy *= 1 + 1e-20 * i; // prevent compiler from optimizing the loop
54  }
55  cout << "energy = " << energy << endl;
56 }
Eigen
Namespace containing all symbols from the Eigen library.
Definition: jet.h:637
e
Array< double, 1, 3 > e(1./3., 0.5, 2.)
main
int main()
Definition: vdw_new.cpp:31
REPEAT
#define REPEAT
Definition: vdw_new.cpp:15
Eigen::PlainObjectBase::setConstant
EIGEN_DEVICE_FUNC Derived & setConstant(Index size, const Scalar &val)
Definition: CwiseNullaryOp.h:361
Vec
Matrix< SCALAR, Eigen::Dynamic, 1 > Vec
Definition: vdw_new.cpp:18
std
Definition: BFloat16.h:88
SIZE
#define SIZE
Definition: vdw_new.cpp:11
E_VDW
SCALAR E_VDW(const Vec &interactions1, const Vec &interactions2)
Definition: vdw_new.cpp:22
Eigen::Matrix
The matrix class, also used for vectors and row-vectors.
Definition: 3rdparty/Eigen/Eigen/src/Core/Matrix.h:178
SCALAR
#define SCALAR
Definition: vdw_new.cpp:7
i
int i
Definition: BiCGSTAB_step_by_step.cpp:9


gtsam
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autogenerated on Fri Nov 1 2024 03:43:08