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openbabel/test/periodictest.cpp
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/**********************************************************************
periodictest.cpp - Unit tests to check implementation of periodic boundary
conditions via the minimum image convention.
Copyright (C) 2018 by Ben Bucior
This file is part of the Open Babel project.
For more information, see <http://openbabel.org/>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
***********************************************************************/
#include "obtest.h"
#include <openbabel/babelconfig.h>
#include <openbabel/atom.h>
#include <openbabel/bond.h>
#include <openbabel/mol.h>
#include <openbabel/obiter.h>
#include <openbabel/generic.h>
#include <openbabel/obconversion.h>
#include <string>
#include <algorithm>
using namespace std;
using namespace OpenBabel;
class PeriodicTester {
public:
PeriodicTester();
void TestLengths(double a, double b, double c);
void TestAngles(double a, double b);
void TestTorsion(double a);
void MakePeriodic(double a = 10.0);
OBMol* GetMol() { return &tmol; }
bool near(double a, double b, double tol = 0.001) {
return (fabs(a - b) < tol);
}
private:
OBMol tmol;
std::vector<OBAtom*> atom_list; // atoms in the consistent order
};
PeriodicTester::PeriodicTester() {
// Builds a made-up test molecule that straddles periodic boundaries
OBAtom* a;
OBBond* b;
tmol.BeginModify();
a = tmol.NewAtom();
a->SetVector(3.0, 3.0, 1.0);
a->SetAtomicNum(8);
atom_list.push_back(a);
a = tmol.NewAtom();
a->SetVector(1.0, 1.0, 1.0);
a->SetAtomicNum(7);
atom_list.push_back(a);
a = tmol.NewAtom();
a->SetVector(-1.0, 1.0, 1.0);
a->SetAtomicNum(6);
atom_list.push_back(a);
a = tmol.NewAtom();
a->SetVector(-1.0, 1.0, -1.0);
a->SetAtomicNum(35);
atom_list.push_back(a);
for (int i=0; i<3; ++i) {
OBAtom *a1, *a2;
a1 = atom_list[i];
a2 = atom_list[i+1];
b = tmol.NewBond();
b->SetBegin(a1);
b->SetEnd(a2);
b->SetBondOrder(1);
a1->AddBond(b);
a2->AddBond(b);
}
tmol.GetBond(atom_list[0], atom_list[1])->SetBondOrder(2);
tmol.EndModify();
OB_COMPARE( tmol.NumAtoms(), 4);
OB_COMPARE( tmol.NumBonds(), 3);
}
void PeriodicTester::TestLengths(double a, double b, double c) {
std::vector<double> expected;
expected.push_back(a);
expected.push_back(b);
expected.push_back(c);
for (int i=0; i<3; ++i) {
OBAtom* a1 = atom_list[i];
OBAtom* a2 = atom_list[i+1];
OB_ASSERT( near( a1->GetDistance(a2), expected[i] ) );
}
}
void PeriodicTester::TestAngles(double a, double b) {
std::vector<double> expected;
expected.push_back(a);
expected.push_back(b);
for (int i=0; i<2; ++i) {
OBAtom* a1 = atom_list[i];
OBAtom* a2 = atom_list[i+1];
OBAtom* a3 = atom_list[i+2];
OB_ASSERT( near( a1->GetAngle(a2, a3), expected[i] ) );
}
}
void PeriodicTester::TestTorsion(double a) {
double torsion = tmol.GetTorsion(atom_list[0], atom_list[1], atom_list[2], atom_list[3]);
OB_ASSERT( near( torsion, a ) );
}
void PeriodicTester::MakePeriodic(double a) {
OBUnitCell *uc = new OBUnitCell;
uc->SetData(a, a, a, 90, 90, 90);
tmol.SetData(uc);
tmol.SetPeriodicMol();
// Wrap coordinates into the UC (<3,3,1>, <1,1,1>, <9,1,1,>, and <9,1,9>)
tmol.BeginModify();
FOR_ATOMS_OF_MOL(a, tmol) {
a->SetVector(uc->WrapCartesianCoordinate(a->GetVector()));
}
tmol.EndModify();
}
void testNonperiodicNegative() {
// Base case to check that the base of the test is working, sans periodicity
PeriodicTester testobj;
testobj.TestLengths(2.0*sqrt(2), 2.0, 2.0); // diagonal hypotenuse, straight, straight
testobj.TestAngles(135.0, 90.0); // diagonal within xy plane, then down in the z direction
testobj.TestTorsion(90.0); // orthogonal planes
}
void testPeriodicFlag() {
// Check that periodic code isn't activated unless specified
PeriodicTester testobj;
testobj.MakePeriodic();
// With periodicity, the code should return the same values as above in
// testNonPeriodicNegative(), even though the coordinates are now wrapped.
testobj.TestLengths(2.0*sqrt(2), 2.0, 2.0);
testobj.TestAngles(135.0, 90.0);
testobj.TestTorsion(90.0);
// If the flag is not activated, the wrapped coordinates behave as-is.
testobj.GetMol()->UnsetFlag(OB_PERIODIC_MOL);
testobj.TestLengths(2.0*sqrt(2), 8.0, 8.0);
testobj.TestAngles(45.0, 90.0);
testobj.TestTorsion(90.0);
}
void testPeriodicCIFWrite() {
PeriodicTester testobj;
testobj.MakePeriodic();
OBMol *mol = testobj.GetMol();
mol->SetTitle("Test for periodic CIFs");
OBConversion conv;
conv.SetOutFormat("cif");
conv.AddOption("g");
std::istringstream full_test_cif(conv.WriteString(mol));
std::string line;
std::string bond_section;
bool found_bonds = false;
while (std::getline(full_test_cif, line)) {
if (found_bonds || line.find("bond") != std::string::npos) {
bond_section.append(line);
bond_section.append("\n"); // This also adds a newline to the end
found_bonds = true;
}
}
const std::string expected_cif_bonds =
" _geom_bond_atom_site_label_1\n\
_geom_bond_atom_site_label_2\n\
_geom_bond_distance\n\
_geom_bond_site_symmetry_2\n\
_ccdc_geom_bond_type\n\
O0 N1 2.82843 . D\n\
N1 C2 2.00000 1_455 S\n\
C2 Br3 2.00000 1_554 S\n\
";
OB_COMPARE(expected_cif_bonds, bond_section);
}
void testPeriodicNoncubic() {
PeriodicTester testobj;
OBMol *mol = testobj.GetMol();
OBUnitCell *uc = new OBUnitCell;
uc->SetData(15, 20, 11, 60.0, 78.8, 128.2); // non-special triclinic parameters
mol->SetData(uc);
mol->SetPeriodicMol();
mol->BeginModify();
FOR_ATOMS_OF_MOL(a, *mol) {
a->SetVector(uc->WrapCartesianCoordinate(a->GetVector()));
}
mol->EndModify();
// When properly wrapped, the original coordinates should be invariant to
// the selected unit cell, as long as it's large enough, etc.
testobj.TestLengths(2.0*sqrt(2), 2.0, 2.0);
testobj.TestAngles(135.0, 90.0);
testobj.TestTorsion(90.0);
}
int periodictest(int argc, char* argv[])
{
int defaultchoice = 1;
int choice = defaultchoice;
if (argc > 1) {
if(sscanf(argv[1], "%d", &choice) != 1) {
printf("Couldn't parse that input as a number\n");
return -1;
}
}
// Define location of file formats for testing
#ifdef FORMATDIR
char env[BUFF_SIZE];
snprintf(env, BUFF_SIZE, "BABEL_LIBDIR=%s", FORMATDIR);
putenv(env);
#endif
switch(choice) {
case 1:
testNonperiodicNegative();
break;
case 2:
testPeriodicFlag();
break;
case 3:
testPeriodicCIFWrite();
break;
case 4:
testPeriodicNoncubic();
break;
default:
cout << "Test number " << choice << " does not exist!\n";
return -1;
}
return(0);
}