Quick environmental dependence (#90)

* Improve field interpolator

* Update imports

csiborgtools/__init__.py

@@ -12,7 +12,7 @@
 # You should have received a copy of the GNU General Public License along
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
-from csiborgtools import clustering, field, match, read  # noqa
+from csiborgtools import clustering, field, match, read, summary  # noqa
 
 from .utils import (center_of_mass, delta2ncells, number_counts,  # noqa
                     periodic_distance, periodic_distance_two_points)  # noqa

csiborgtools/summary/__init__.py

@@ -19,3 +19,4 @@ from .overlap_summary import weighted_stats  # noqa
 from .overlap_summary import NPairsOverlap, PairOverlap, get_cross_sims         # noqa
 from .pk_summary import PKReader                                                # noqa
 from .tpcf_summary import TPCFReader                                            # noqa
+from .field_interp import read_interpolated_field                               # noqa

csiborgtools/summary/field_interp.py

@@ -0,0 +1,77 @@
+# Copyright (C) 2023 Richard Stiskalek
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+# Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+import numpy
+from tqdm import tqdm
+
+
+def read_interpolated_field(survey_name, kind, galaxy_index, paths, MAS, grid,
+                            in_rsp, rand_data=False, verbose=True):
+    """
+    Read in the interpolated field at the galaxy positions, and reorder the
+    data to match the galaxy index.
+
+    Parameters
+    ----------
+    survey_name : str
+        Survey name.
+    kind : str
+        Field kind.
+    galaxy_index : 1-dimensional array
+        Galaxy indices to read in.
+    paths : py:class:`csiborgtools.read.Paths`
+        Paths manager.
+    MAS : str
+        Mass assignment scheme.
+    grid : int
+        Grid size.
+    in_rsp : bool
+        Whether to read in the field in redshift space.
+    rand_data : bool, optional
+        Whether to read in the random field data instead of the galaxy field.
+    verbose : bool, optional
+        Verbosity flag.
+
+    Returns
+    -------
+    3-dimensional array of shape (nsims, len(galaxy_index), nsmooth)
+    """
+    nsims = paths.get_ics("csiborg")
+    for i, nsim in enumerate(tqdm(nsims,
+                                  desc="Reading fields",
+                                  disable=not verbose)):
+        fpath = paths.field_interpolated(
+            survey_name, kind, MAS, grid, nsim, in_rsp=in_rsp)
+        data = numpy.load(fpath)
+        out_ = data["val"] if not rand_data else data["rand_val"]
+
+        if i == 0:
+            out = numpy.empty((len(nsims), *out_.shape), dtype=out_.dtype)
+            indxs = data["indxs"]
+
+        out[i] = out_
+
+    # Reorder the data to match the survey index.
+    ind2pos = {v: k for k, v in enumerate(indxs)}
+    ks = numpy.empty(len(galaxy_index), dtype=numpy.int64)
+
+    for i, k in enumerate(galaxy_index):
+        j = ind2pos.get(k, None)
+        if j is None:
+            raise ValueError(f"There is no galaxy with index {k} in the "
+                             "interpolated field.")
+        ks[i] = j
+
+    return out[:, ks, :]