From 54541645f929f8792120528ab88b5c194a162493 Mon Sep 17 00:00:00 2001
From: Melissa DeLucchi <delucchi@andrew.cmu.edu>
Date: Fri, 14 Jun 2024 15:30:03 -0400
Subject: [PATCH] Cross-correlation alignment method and docstrings.

---
 src/corrgi/__init__.py              |  3 ---
 src/corrgi/alignment.py             | 31 ++++++++++++++++++++++++++---
 src/corrgi/example_module.py        | 23 ---------------------
 tests/corrgi/test_alignment.py      | 12 ++++++++++-
 tests/corrgi/test_example_module.py | 13 ------------
 5 files changed, 39 insertions(+), 43 deletions(-)
 delete mode 100644 src/corrgi/example_module.py
 delete mode 100644 tests/corrgi/test_example_module.py

diff --git a/src/corrgi/__init__.py b/src/corrgi/__init__.py
index b564b85..e69de29 100644
--- a/src/corrgi/__init__.py
+++ b/src/corrgi/__init__.py
@@ -1,3 +0,0 @@
-from .example_module import greetings, meaning
-
-__all__ = ["greetings", "meaning"]
diff --git a/src/corrgi/alignment.py b/src/corrgi/alignment.py
index 9171627..4c4213b 100644
--- a/src/corrgi/alignment.py
+++ b/src/corrgi/alignment.py
@@ -16,7 +16,16 @@
 
 
 def autocorrelation_alignment(catalog: Catalog) -> PixelAlignment:
-    """TODO"""
+    """Determine all pairs of partitions that should be correlated within the same catalog.
+
+    This considers all combinations, without duplicates between the "primary" and "join"
+    pixels in the alignment.
+
+    Args:
+        catalog (Catalog): catalog for autocorrelation
+    Returns:
+        alignment object where the `aligned` columns simply match the left pixel.
+    """
     upper_triangle = [
         [left.order, left.pixel, right.order, right.pixel, left.order, left.pixel]
         for (left, right) in itertools.combinations(catalog.get_healpix_pixels(), 2)
@@ -33,5 +42,21 @@ def autocorrelation_alignment(catalog: Catalog) -> PixelAlignment:
 
 
 def crosscorrelation_alignment(catalog_left: Catalog, catalog_right: Catalog) -> PixelAlignment:
-    """TODO"""
-    pass
+    """Determine all pairs of partitions that should be correlated between two catalogs.
+
+    This considers the full cross-product of pixels.
+
+    Args:
+        catalog_left (Catalog): left side of the cross-correlation
+        catalog_right (Catalog): right side of the cross-correlation
+    Returns:
+        alignment object where the `aligned` columns simply match the left pixel.
+    """
+    full_product = [
+        [left.order, left.pixel, right.order, right.pixel, left.order, left.pixel]
+        for (left, right) in itertools.product(
+            catalog_left.get_healpix_pixels(), catalog_right.get_healpix_pixels()
+        )
+    ]
+    result_mapping = pd.DataFrame(full_product, columns=column_names)
+    return PixelAlignment(catalog_left.pixel_tree, result_mapping, PixelAlignmentType.OUTER)
diff --git a/src/corrgi/example_module.py b/src/corrgi/example_module.py
deleted file mode 100644
index f76e837..0000000
--- a/src/corrgi/example_module.py
+++ /dev/null
@@ -1,23 +0,0 @@
-"""An example module containing simplistic functions."""
-
-
-def greetings() -> str:
-    """A friendly greeting for a future friend.
-
-    Returns
-    -------
-    str
-        A typical greeting from a software engineer.
-    """
-    return "Hello from LINCC-Frameworks!"
-
-
-def meaning() -> int:
-    """The meaning of life, the universe, and everything.
-
-    Returns
-    -------
-    int
-        The meaning of life.
-    """
-    return 42
diff --git a/tests/corrgi/test_alignment.py b/tests/corrgi/test_alignment.py
index 5286496..8840b44 100644
--- a/tests/corrgi/test_alignment.py
+++ b/tests/corrgi/test_alignment.py
@@ -1,8 +1,18 @@
 import hipscat
-from corrgi.alignment import autocorrelation_alignment
+from corrgi.alignment import autocorrelation_alignment, crosscorrelation_alignment
 
 
 def test_autocorrelation_alignment(data_catalog_dir):
     data_catalog = hipscat.read_from_hipscat(data_catalog_dir)
     alignment = autocorrelation_alignment(data_catalog)
     assert len(alignment.pixel_mapping) == 28
+
+
+def test_crosscorrelation_alignment(dr7_lrg_catalog_dir, dr7_lrg_rand_catalog_dir):
+    dr7_catalog = hipscat.read_from_hipscat(dr7_lrg_catalog_dir)
+    dr7_rand_catalog = hipscat.read_from_hipscat(dr7_lrg_rand_catalog_dir)
+    alignment = crosscorrelation_alignment(dr7_catalog, dr7_rand_catalog)
+    ## dr7_catalog has 12 partitions
+    ## dr7_rand_catalog has 22 partitions
+    ## 12*21 = 252
+    assert len(alignment.pixel_mapping) == 252
diff --git a/tests/corrgi/test_example_module.py b/tests/corrgi/test_example_module.py
deleted file mode 100644
index 64cb10f..0000000
--- a/tests/corrgi/test_example_module.py
+++ /dev/null
@@ -1,13 +0,0 @@
-from corrgi import example_module
-
-
-def test_greetings() -> None:
-    """Verify the output of the `greetings` function"""
-    output = example_module.greetings()
-    assert output == "Hello from LINCC-Frameworks!"
-
-
-def test_meaning() -> None:
-    """Verify the output of the `meaning` function"""
-    output = example_module.meaning()
-    assert output == 42