Add a linspace class method

.pre-commit-config.yaml

@@ -1,7 +1,7 @@
 repos:
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.1.5
+  rev: v0.6.7
   hooks:
     # Run the linter.
     - id: ruff

cxotime/__init__.py

@@ -5,6 +5,7 @@
 
 from .convert import *  # noqa: F401, F403
 from .cxotime import *  # noqa: F401, F403
+from .utils import get_range_in_chunks
 
 __version__ = ska_helpers.get_version(__package__)
 

cxotime/tests/test_cxotime.py

@@ -3,6 +3,7 @@
 Simple test of CxoTime.  The base Time object is extremely well
 tested, so this simply confirms that the add-on in CxoTime works.
 """
+
 import io
 import time
 from dataclasses import dataclass

cxotime/tests/test_utils.py

@@ -0,0 +1,89 @@
+import astropy.units as u
+import numpy as np
+import pytest
+
+from cxotime import CxoTime, get_range_in_chunks
+
+
+@pytest.mark.parametrize(
+    "start, stop, dt_max, expected_len, expected_values",
+    [
+        ("2000:001", "2000:001", 1 * u.day, 2, ["2000:001", "2000:001"]),
+        (
+            "2000:001",
+            "2000:005",
+            24 * u.hour,
+            5,
+            ["2000:001", "2000:002", "2000:003", "2000:004", "2000:005"],
+        ),
+        (
+            "2000:001",
+            "2000:005",
+            2880 * u.minute,
+            3,
+            ["2000:001", "2000:003", "2000:005"],
+        ),
+        ("2000:001", "2000:005", 10 * 86400 * u.second, 2, ["2000:001", "2000:005"]),
+    ],
+)
+def test_get_range_in_chunks(start, stop, dt_max, expected_len, expected_values):
+    start = CxoTime(start)
+    stop = CxoTime(stop)
+    result = get_range_in_chunks(start, stop, dt_max)
+
+    # Confirm that the time intervals are uniform if there is any interval
+    if len(result) > 2:
+        assert all(
+            np.isclose((result[1:] - result[:-1]).sec, dt_max.to(u.second).value)
+        )
+
+    # Confirm that the time range is covered
+    assert result[0] == start
+    assert result[-1] == stop
+
+    # And confirm that the result is as expected
+    assert len(result) == expected_len
+    assert all(a == CxoTime(b) for a, b in zip(result, expected_values, strict=False))
+
+
+# Add a test of a negative time range
+def test_get_range_in_chunks_negative():
+    start = CxoTime("2000:005")
+    stop = CxoTime("2000:001")
+    dt_max = 24 * u.hour
+    result = get_range_in_chunks(start, stop, dt_max)
+    assert len(result) == 5
+    expected_values = ["2000:005", "2000:004", "2000:003", "2000:002", "2000:001"]
+    assert all(a == CxoTime(b) for a, b in zip(result, expected_values, strict=False))
+
+
+# Add a test that shows that the time range is covered even if the time range is less than dt_max
+def test_get_range_in_chunks_small():
+    start = CxoTime("2020:001")
+    stop = CxoTime("2020:005")
+    dt_max = 30 * u.day
+    result = get_range_in_chunks(start, stop, dt_max)
+    assert len(result) == 2
+    assert all(
+        a == CxoTime(b) for a, b in zip(result, ["2020:001", "2020:005"], strict=False)
+    )
+
+
+# Add a test that shows we get an error if dt_max is zero
+def test_get_range_in_chunks_zero():
+    start = CxoTime("2020:001")
+    stop = CxoTime("2020:005")
+    dt_max = 0 * u.day
+    with pytest.raises(ValueError) as excinfo:
+        get_range_in_chunks(start, stop, dt_max)
+    assert "dt_max must be positive nonzero" in str(excinfo.value)
+
+
+# Add a test that shows we get an error if dt_max is negative
+def test_get_range_in_chunks_negative_dt():
+    start = CxoTime("2020:001")
+    stop = CxoTime("2020:005")
+    dt_max = -1 * u.day
+    with pytest.raises(ValueError) as excinfo:
+        get_range_in_chunks(start, stop, dt_max)
+    assert "dt_max must be positive nonzero" in str(excinfo.value)

cxotime/utils.py

@@ -0,0 +1,44 @@
+# Licensed under a 3-clause BSD style license - see LICENSE.rst
+import astropy.units as u
+import numpy as np
+
+from cxotime import CxoTime, CxoTimeLike
+
+
+def get_range_in_chunks(start: CxoTimeLike, stop: CxoTimeLike, dt_max: u.Quantity):
+    """
+    Get uniform time chunks for a given time range.
+
+    Output times are spaced uniformly spaced by up to ``dt_max`` and cover the time
+    range from ``start`` to ``stop``.
+
+    Parameters
+    ----------
+    start : CxoTime
+        Start time of the time range.
+    stop : CxoTime
+        Stop time of the time range.
+    dt_max : u.Quantity (timelike)
+        Maximum time interval for each chunk.
+
+    Returns
+    -------
+    CxoTime
+        CxoTime with time bin edges for each chunk.
+    """
+    start = CxoTime(start)
+    stop = CxoTime(stop)
+
+    # Require that dt_max is a positive nonzero quantity
+    if dt_max <= 0 * u.s:
+        raise ValueError("dt_max must be positive nonzero")
+
+    # Let this work if start > stop, but flip the sign of dt_max
+    if start > stop:
+        dt_max = -dt_max
+
+    # Calculate chunks to cover time range, handling edge case of start == stop
+    n_chunk = max(np.ceil(float((stop - start) / dt_max)), 1)
+    dt = (stop - start) / n_chunk
+    times = start + np.arange(n_chunk + 1) * dt
+    return times

ruff-base.toml

@@ -0,0 +1,59 @@
+# Copied originally from pandas. This config requires ruff >= 0.2.
+target-version = "py311"
+
+# fix = true
+lint.unfixable = []
+
+lint.select = [
+  "I", # isort
+  "F", # pyflakes
+  "E", "W", # pycodestyle
+  "YTT", # flake8-2020
+  "B", # flake8-bugbear
+  "Q", # flake8-quotes
+  "T10", # flake8-debugger
+  "INT", # flake8-gettext
+  "PLC", "PLE", "PLR", "PLW", # pylint
+  "PIE", # misc lints
+  "PYI", # flake8-pyi
+  "TID", # tidy imports
+  "ISC", # implicit string concatenation
+  "TCH", # type-checking imports
+  "C4", # comprehensions
+  "PGH" # pygrep-hooks
+]
+
+# Some additional rules that are useful
+lint.extend-select = [
+"UP009",  # UTF-8 encoding declaration is unnecessary
+"SIM118",  # Use `key in dict` instead of `key in dict.keys()`
+"D205",  # One blank line required between summary line and description
+"ARG001",  # Unused function argument
+"RSE102",  # Unnecessary parentheses on raised exception
+"PERF401",  # Use a list comprehension to create a transformed list
+]
+
+lint.ignore = [
+  "ISC001", # Disable this for compatibility with ruff format
+  "E402", # module level import not at top of file
+  "E731", # do not assign a lambda expression, use a def
+  "PLR2004", # Magic number
+  "B028", # No explicit `stacklevel` keyword argument found
+  "PLR0913", # Too many arguments to function call
+  "PLR1730", # Checks for if statements that can be replaced with min() or max() calls
+]
+
+extend-exclude = [
+  "docs",
+]
+
+[lint.pycodestyle]
+max-line-length = 100 # E501 reports lines that exceed the length of 100.
+
+[lint.extend-per-file-ignores]
+"__init__.py" = ["E402", "F401", "F403"]
+# For tests:
+# - D205: Don't worry about test docstrings
+# - ARG001: Unused function argument false positives for some fixtures
+# - E501: Line-too-long
+"**/tests/test_*.py" = ["D205", "ARG001", "E501"]

ruff.toml

@@ -1,58 +1,25 @@
-# Copied originally from pandas
-target-version = "py310"
+extend = "ruff-base.toml"
 
-# fix = true
-unfixable = []
-
-select = [
-  "I", # isort
-  "F", # pyflakes
-  "E", "W", # pycodestyle
-  "YTT", # flake8-2020
-  "B", # flake8-bugbear
-  "Q", # flake8-quotes
-  "T10", # flake8-debugger
-  "INT", # flake8-gettext
-  "PLC", "PLE", "PLR", "PLW", # pylint
-  "PIE", # misc lints
-  "PYI", # flake8-pyi
-  "TID", # tidy imports
-  "ISC", # implicit string concatenation
-  "TCH", # type-checking imports
-  "C4", # comprehensions
-  "PGH" # pygrep-hooks
-]
-
-# Some additional rules that are useful
-extend-select = [
-"UP009",  # UTF-8 encoding declaration is unnecessary
-"SIM118",  # Use `key in dict` instead of `key in dict.keys()`
-"D205",  # One blank line required between summary line and description
-"ARG001",  # Unused function argument
-"RSE102",  # Unnecessary parentheses on raised exception
-"PERF401",  # Use a list comprehension to create a transformed list
+# These are files to exclude for this project.
+extend-exclude = [
+  # "**/*.ipynb",  # commonly not ruff-compliant
 ]
 
-ignore = [
-  "ISC001", # Disable this for compatibility with ruff format
-  "B028", # No explicit `stacklevel` keyword argument found
+# These are rules that commonly cause many ruff warnings. Code will be improved by
+# incrementally fixing code to adhere to these rules, but for practical purposes they
+# can be ignored by uncommenting each one. You can also add to this list as needed.
+lint.extend-ignore = [
   "B905", # `zip()` without an explicit `strict=` parameter
-  "E731", # do not assign a lambda expression, use a def
-  "PLC1901", # compare-to-empty-string
+  # "PLC1901", # compare-to-empty-string
+  # "PLR0911", # Too many returns
   "PLR0912", # Too many branches
-  "PLR2004", # Magic number
+  # "PLR0915", # Too many statements
+  # "PGH004", # Use specific rule codes when using `noqa`
+  # "C401", # Unnecessary generator (rewrite as a `set` comprehension)
+  # "C402", # Unnecessary generator (rewrite as a dict comprehension)
+  # "C405", # Unnecessary `list` literal (rewrite as a `set` literal)
+  # "C408", # Unnecessary `dict` call (rewrite as a literal)
+  # "C416", # Unnecessary `dict` comprehension (rewrite using `dict()`)
+  # "G010", # warn is deprecated in favor of warning
+  # "PYI056", # Calling `.append()` on `__all__` may not be supported by all type checkers
 ]
-
-extend-exclude = [
-  "docs",
-]
-
-[pycodestyle]
-max-line-length = 100 # E501 reports lines that exceed the length of 100.
-
-[lint.extend-per-file-ignores]
-"__init__.py" = ["E402", "F401", "F403"]
-# For tests:
-# - D205: Don't worry about test docstrings
-# - ARG001: Unused function argument false positives for some fixtures
-"**/tests/test_*.py" = ["D205", "ARG001"]