chore: make csaps optional

docs/source/getting-started.rst

@@ -64,4 +64,31 @@ are sufficient for most use cases.
     * - `pyqtgraph <https://pyqtgraph.readthedocs.io/en/latest/>`_
       - Interactive plotting (i.e., imagetool)
 
+For the full list of dependencies, see the `requirements.txt` file.
+
 See the :doc:`userguide` to start using ERLabPy!
+
+
+Optional dependencies
+---------------------
+
+The following packages are optional dependencies that are not installed by
+default. They are used in only specific functions, or is not used at all but is
+listed just for convenience.
+
+.. list-table::
+    :header-rows: 1
+    :stub-columns: 1
+    :widths: auto
+
+    * - Package
+      - Description
+    * - `csaps <https://github.com/espdev/csaps>`_
+      - Multidimensional smoothing splines
+    * - `hvplot <https://github.com/holoviz/hvplot>`_ and `bokeh
+        <https://github.com/bokeh/bokeh>`_
+      - Interactive plotting
+    * - `cmasher <https://cmasher.readthedocs.io>`_,
+        `cmocean <https://matplotlib.org/cmocean/>`_, and
+        `colorcet <https://colorcet.holoviz.org>`_
+      - More colormaps!

environment.yml

@@ -48,6 +48,5 @@ dependencies:
   - pyperclip
   - pip:
     - pyqt6>=6.2.2
-    - csaps
     - igor2 @ git+https://github.com/kmnhan/igor2@master
     - arpes @ git+https://github.com/kmnhan/arpes@master

environment_apple.yml

@@ -52,6 +52,5 @@ dependencies:
   - pyperclip
   - pip:
     - pyqt6>=6.2.2
-    - csaps
     - igor2 @ git+https://github.com/kmnhan/igor2@master
     - arpes @ git+https://github.com/kmnhan/arpes@master

environment_nogit.yml

@@ -52,4 +52,3 @@ dependencies:
   - pyperclip
   - pip:
     - pyqt6>=6.2.2
-    - csaps

environment_nogit_mkl.yml

@@ -52,4 +52,3 @@ dependencies:
   - pyperclip
   - pip:
     - pyqt6>=6.2.2
-    - csaps

pyproject.toml

@@ -30,7 +30,6 @@ dependencies = [
     "lmfit>=1.2.0",
     "uncertainties>=3.0.1",
     "iminuit>=2.25.2",
-    "csaps",
     "matplotlib>=3.8.0",
     "xarray",
     "h5netcdf",

requirements.txt

@@ -7,7 +7,6 @@ scipy>=1.8.0
 lmfit>=1.2.0
 uncertainties>=3.0.1
 iminuit>=2.25.2
-csaps
 matplotlib>=3.8.0
 xarray
 h5netcdf

src/erlab/analysis/fit/spline.py

@@ -1,6 +1,13 @@
-import csaps
 import xarray as xr
 
+try:
+    import csaps
+except ImportError as e:
+    raise ImportError(
+        "The `csaps` package is required for this module. "
+        "Please install it using `pip install csaps`."
+    ) from e
+
 
 def xcsaps(
     arr: xr.DataArray, **kwargs: dict