Support timedelta64 dtype as input (#2884)

Map np.timedelta64 to GMT_LONG in clib/session.py's DTYPES dictionary.
Added a unit test in test_clib_put_vectors.py to test passing a numpy array
with timedelta64 dtypes of various time units (year to microsecond).

* Add unit test for plotting timedelta64 data

Make a 2D plot with Forecast Days (timedelta64) on the x-axis, and RMSE on the y-axis.

* Update test_plot_timedelta64 baseline img with GMT 6.5.0 and gs 10.02.1

Author: weiji14

pygmt/clib/session.py

@@ -85,6 +85,7 @@
     np.float64: "GMT_DOUBLE",
     np.str_: "GMT_TEXT",
     np.datetime64: "GMT_DATETIME",
+    np.timedelta64: "GMT_LONG",
 }
 
 # Load the GMT library outside the Session class to avoid repeated loading.

pygmt/tests/baseline/test_plot_timedelta64.png.dvc

@@ -0,0 +1,5 @@
+outs:
+- md5: 8edddcec764d244053c4d675e98732b9
+  size: 13201
+  path: test_plot_timedelta64.png
+  hash: md5

pygmt/tests/test_clib_put_vector.py

@@ -168,6 +168,37 @@ def test_put_vector_string_dtype():
                     npt.assert_array_equal(output["y"], expected_vectors[j])
 
 
+def test_put_vector_timedelta64_dtype():
+    """
+    Passing timedelta64 type vectors with various time units (year, month,
+    week, day, hour, minute, second, millisecond, microsecond) to a dataset.
+    """
+    for unit in ["Y", "M", "W", "D", "h", "m", "s", "ms", "μs"]:
+        with clib.Session() as lib, GMTTempFile() as tmp_file:
+            dataset = lib.create_data(
+                family="GMT_IS_DATASET|GMT_VIA_VECTOR",
+                geometry="GMT_IS_POINT",
+                mode="GMT_CONTAINER_ONLY",
+                dim=[1, 5, 1, 0],  # columns, rows, layers, dtype
+            )
+            timedata = np.arange(np.timedelta64(0, unit), np.timedelta64(5, unit))
+            lib.put_vector(dataset, column=0, vector=timedata)
+            # Turns out wesn doesn't matter for Datasets
+            wesn = [0] * 6
+            # Save the data to a file to see if it's being accessed correctly
+            lib.write_data(
+                family="GMT_IS_VECTOR",
+                geometry="GMT_IS_POINT",
+                mode="GMT_WRITE_SET",
+                wesn=wesn,
+                output=tmp_file.name,
+                data=dataset,
+            )
+            # Load the data and check that it's correct
+            newtimedata = tmp_file.loadtxt(unpack=True, dtype=f"timedelta64[{unit}]")
+            npt.assert_equal(actual=newtimedata, desired=timedata)
+
+
 def test_put_vector_invalid_dtype():
     """
     Check that it fails with an exception for invalid data types.

pygmt/tests/test_plot.py

@@ -453,6 +453,26 @@ def test_plot_datetime():
     return fig
 
 
+@pytest.mark.mpl_image_compare
+def test_plot_timedelta64():
+    """
+    Test plotting numpy.timedelta64 input data.
+    """
+    fig = Figure()
+    fig.basemap(
+        projection="X8c/5c",
+        region=[0, 8, 0, 10],
+        frame=["WSne", "xaf+lForecast Days", "yaf+lRMSE"],
+    )
+    fig.plot(
+        x=np.arange(np.timedelta64(0, "D"), np.timedelta64(8, "D")),
+        y=np.geomspace(start=0.1, stop=9, num=8),
+        style="c0.2c",
+        pen="1p",
+    )
+    return fig
+
+
 @pytest.mark.mpl_image_compare(
     filename="test_plot_ogrgmt_file_multipoint_default_style.png"
 )