fix IQazimuthal.to_workspace() needed for saving to NXcanSAS

src/drtsans/dataobjects.py

@@ -18,6 +18,8 @@
     "verify_same_q_bins",
 ]
 
+QBINS_EQUAL_DECIMALS = 8
+
 
 class DataType(Enum):
     WORKSPACE2D = "Workspace2D"
@@ -563,8 +565,8 @@ class IQazimuthal(namedtuple("IQazimuthal", "intensity error qx qy delta_qx delt
 
     if intensity is 2D, and qx and qy are 1D: In this constructor, it is assumed that intensity 2D array
     will match
-    qx = [[qx0, qx1, ...], [qx0, qx1, ...], ...]
-    qy = [[qy0, qy0, ...], [qy1, qy1, ...], ...]
+    qx = [[qx0, qx0, ...], [qx1, qx1, ...], ...]
+    qy = [[qy0, qy1, ...], [qy0, qy1, ...], ...]
     because qx and qy will be created in such style.
     """
 
@@ -711,14 +713,41 @@ def to_workspace(self, name=None):
         if name is None:
             name = mtd.unique_hidden_name()
 
+        def flatten_unique_vals(a: np.ndarray):
+            """
+            Helper function to get the unique values with a tolerance preserving order
+
+            Steps:
+            1. Flatten the array
+            2. Round the array to QBINS_EQUAL_DECIMALS decimals
+            3. Find the indices of the first location of each unique element in the rounded array
+            4. Use the indices to return the unique elements from the original array
+            """
+            b = a.flatten()
+            return b[np.unique(b.round(QBINS_EQUAL_DECIMALS), return_index=True)[1]]
+
+        # get the unique qx and qy values
+        qx_ws = flatten_unique_vals(self.qx)
+        qy_ws = flatten_unique_vals(self.qy)
+
+        # reshape intensity and error as needed for CreateWorkspace with qy as vertical axis
+        qx_ws_len = len(qx_ws)
+        qy_ws_len = len(qy_ws)
+        if len(self.intensity.shape) == 1 and len(self.intensity) == len(qx_ws):
+            intensity_ws = self.intensity
+            error_ws = self.error
+        else:
+            intensity_ws = self.intensity.ravel().reshape((qx_ws_len, qy_ws_len)).T
+            error_ws = self.error.ravel().reshape((qx_ws_len, qy_ws_len)).T
+
         ws = CreateWorkspace(
-            DataX=self.qx,
+            DataX=qx_ws,
             UnitX="MomentumTransfer",
-            VerticalAxisValues=self.qy,
+            VerticalAxisValues=qy_ws,
             VerticalAxisUnit="MomentumTransfer",
-            NSpec=self.qy.size,
-            DataY=self.intensity,
-            DataE=self.error,
+            NSpec=qy_ws.size,
+            DataY=intensity_ws,
+            DataE=error_ws,
             OutputWorkspace=name,
             # dx=
             EnableLogging=False,

tests/unit/drtsans/test_dataobjects.py

@@ -535,28 +535,64 @@ def test_to_workspace_1D(self):
         ws = iqaz.to_workspace()
 
         ws_expected = CreateWorkspace(
-            DataX=qx, DataY=I, DataE=E, VerticalAxisValues=qy, VerticalAxisUnit="MomentumTransfer", NSpec=len(qy)
+            DataX=qx,
+            DataY=I,
+            DataE=E,
+            UnitX="MomentumTransfer",
+            VerticalAxisValues=qy,
+            VerticalAxisUnit="MomentumTransfer",
+            NSpec=len(qy),
         )
 
-        assert CompareWorkspaces(ws, ws_expected)
+        assert CompareWorkspaces(ws, ws_expected).Result is True
+
+    def test_to_workspace_1D_flattened_Q2D(self):
+        """test with one-dimensional Qx, Qy, I where Qx and Qy have been flattened from 2D"""
+
+        i = np.array([1, 2, 3, 4, 5, 6])
+        e = np.array([4, 5, 6, 7, 8, 9])
+        qx = np.array([7, 7, 8, 8, 9, 9])
+        qy = np.array([11, 12, 11, 12, 11, 12])
+
+        iqaz = IQazimuthal(i, e, qx, qy)
+
+        ws = iqaz.to_workspace()
+
+        ws_expected = CreateWorkspace(
+            DataX=[7, 8, 9],
+            DataY=[1, 3, 5, 2, 4, 6],
+            DataE=[4, 6, 8, 5, 7, 9],
+            NSpec=2,
+            UnitX="MomentumTransfer",
+            VerticalAxisValues=[11, 12],
+            VerticalAxisUnit="MomentumTransfer",
+        )
+
+        assert CompareWorkspaces(ws, ws_expected).Result is True
 
     def test_to_workspace_2D(self):
         """test with two-dimensional Qx, Qy, I"""
 
-        i = np.array([[1, 2], [3, 4]])
-        e = np.array([[4, 5], [6, 7]])
-        qx = np.array([[7, 8], [9, 10]])
-        qy = np.array([[11, 12], [12, 13]])
+        i = np.array([[1, 2], [3, 4], [5, 6]])
+        e = np.array([[4, 5], [6, 7], [8, 9]])
+        qx = np.array([[7, 7], [8, 8], [9, 9]])
+        qy = np.array([[11, 12], [11, 12], [11, 12]])
 
         iqaz = IQazimuthal(i, e, qx, qy)
 
         ws = iqaz.to_workspace()
 
         ws_expected = CreateWorkspace(
-            DataX=qx, DataY=i, DataE=e, NSpec=4, VerticalAxisValues=qy, VerticalAxisUnit="MomentumTransfer"
+            DataX=qx[:, 0],
+            DataY=i.T,
+            DataE=e.T,
+            NSpec=2,
+            UnitX="MomentumTransfer",
+            VerticalAxisValues=qy[0, :],
+            VerticalAxisUnit="MomentumTransfer",
         )
 
-        assert CompareWorkspaces(ws, ws_expected)
+        assert CompareWorkspaces(ws, ws_expected).Result is True
 
     def test_to_workspace_I2D_Q1D(self):
         """test with two-dimensional I, one-dimensional Qx, Qy"""
@@ -571,10 +607,16 @@ def test_to_workspace_I2D_Q1D(self):
         ws = iqaz.to_workspace()
 
         ws_expected = CreateWorkspace(
-            DataX=qx, DataY=i, DataE=e, Nspec=3, VerticalAxisValues=qy, VerticalAxisUnit="MomentumTransfer"
+            DataX=qx,
+            DataY=i.T,
+            DataE=e.T,
+            Nspec=3,
+            UnitX="MomentumTransfer",
+            VerticalAxisValues=qy,
+            VerticalAxisUnit="MomentumTransfer",
         )
 
-        assert CompareWorkspaces(ws, ws_expected)
+        assert CompareWorkspaces(ws, ws_expected).Result is True
 
 
 class TestTesting: