Merge pull request #286 from fnalacceleratormodeling/egstern/285-miss…

…ing-python-binding-for-lattice-copy-constructor

added binding and test

src/synergia/lattice/lattice_pywrap.cc

@@ -330,6 +330,9 @@ PYBIND11_MODULE(lattice, m)
  "Construct an empty latttice.", 
  "name"_a )
 
+ .def( py::init<Lattice const&>(),
+ "Construct a copy of a lattice." )
+
  .def( py::init<std::string const&, Reference_particle const&>(), 
  "Construct an empty latttice with given reference particle.", 
  "name"_a,

src/synergia/lattice/tests/test_lattice.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 import pytest
+import synergia
 from synergia.lattice import Lattice, Lattice_element
 from synergia.foundation import Reference_particle
 
@@ -44,3 +45,41 @@ def test_set_reference_particle_energy():
  lattice.set_reference_particle(reference_particle)
  lattice.get_reference_particle().set_total_energy(total_energy + 1)
  assert lattice.get_reference_particle().get_total_energy() == total_energy + 1.0
+
+def test_copy_constructor():
+ lattice_txt = """
+q1: quadrupole, l=0.5, k1=0.2;
+b1: sbend, angle=0.05, l=2.0;
+machine: sequence, refer=entry, l=6.0;
+ q1, at=1.0;
+ b1, at=2.5;
+ endsequence;
+ beam, particle=proton, energy=1.5;
+"""
+
+ reader = synergia.lattice.MadX_reader()
+ reader.parse(lattice_txt)
+ lattice1 = reader.get_lattice('machine')
+ assert lattice1.get_length() == 6.0
+
+ lattice2 = lattice1
+ assert lattice2.get_length() == 6.0
+
+ # Are lattice1 and lattice2 the same object?
+ assert id(lattice1) == id(lattice2)
+ # Change to an element in lattice2 is reflected in lattice1
+ elem = lattice2.get_elements()[1]
+ elem.set_double_attribute('xyzzy', 3.0)
+ assert lattice1.get_elements()[1].get_double_attribute('xyzzy') == 3.0
+
+ # lattice3 should be a seperate object with copies of the elements
+ lattice3 = synergia.lattice.Lattice(lattice1)
+ assert lattice3.get_length() == 6.0
+
+ assert id(lattice1) != id(lattice3)
+
+ # change parameters in an element of lattice3 to check that it doesn't
+ # affect lattice1
+ elem = lattice3.get_elements()[0]
+ elem.set_double_attribute('foo', 4)
+ assert not lattice1.get_elements()[0].has_double_attribute('foo')