cleanup with operators/value tracker/current_state

- current_state now always computes its derived values
- it implements a copy function

tests/test_current_state.py

@@ -0,0 +1,31 @@
+import numpy as np
+import pytest
+
+from scgenerator.operators import CurrentState
+
+
+def test_creation():
+    x = (np.linspace(0, 1, 128, dtype=complex),)
+    cs = CurrentState(1.0, 0, 0.1, x, 1.0)
+
+    assert cs.converter is np.fft.ifft
+    assert cs.stats == {}
+    assert np.allclose(cs.spectrum2, np.abs(np.fft.ifft(x)) ** 2)
+
+    with pytest.raises(ValueError):
+        cs = CurrentState(1.0, 0, 0.0, x, 1.0, spectrum2=np.abs(x) ** 3)
+
+    cs = CurrentState(1.0, 0, 0.1, x, 1.0, spectrum2=x.copy(), field=x.copy(), field2=x.copy())
+
+    assert np.allclose(cs.spectrum2, cs.spectrum)
+    assert np.allclose(cs.spectrum, cs.field)
+    assert np.allclose(cs.field, cs.field2)
+
+
+def test_copy():
+    x = (np.linspace(0, 1, 128, dtype=complex),)
+    cs = CurrentState(1.0, 0, 0.1, x, 1.0)
+    cs2 = cs.copy()
+
+    assert cs.spectrum is not cs2.spectrum
+    assert np.all(cs.field2 == cs2.field2)