diff --git a/hiwenet/__init__.py b/hiwenet/__init__.py
index 07c8a69..98bbb16 100644
--- a/hiwenet/__init__.py
+++ b/hiwenet/__init__.py
@@ -4,16 +4,19 @@
 
 """
 
+__all__ = ['extract', 'pairwise_dist', 'run_cli', 'more_metrics']
+
 from sys import version_info
 
 if version_info.major==2 and version_info.minor==7:
-    from hiwenet import extract, run_cli
+    import more_metrics
+    from pairwise_dist import extract, run_cli
 elif version_info.major > 2:
-    from hiwenet.hiwenet import extract, run_cli
+    from hiwenet import more_metrics
+    from hiwenet.pairwise_dist import extract, run_cli
 else:
-    raise NotImplementedError('hiwenet supports only 2.7.13 or 3+. Upgrade to Python 3+ is recommended.')
+    raise NotImplementedError('hiwenet supports only 2.7 or 3+. Upgrade to Python 3+ is recommended.')
 
-__all__ = ['extract', 'hiwenet', 'run_cli']
 from ._version import get_versions
 __version__ = get_versions()['version']
 del get_versions
diff --git a/hiwenet/__main__.py b/hiwenet/__main__.py
index a764b5b..01b6612 100644
--- a/hiwenet/__main__.py
+++ b/hiwenet/__main__.py
@@ -1,9 +1,9 @@
 from sys import version_info
 
 if version_info.major==2 and version_info.minor==7:
-    from hiwenet import run_cli
+    from pairwise_dist import run_cli
 elif version_info.major > 2:
-    from hiwenet.hiwenet import run_cli
+    from hiwenet.pairwise_dist import run_cli
 else:
     raise NotImplementedError('hiwenet supports only 2.7.13 or 3+. Upgrade to Python 3+ is recommended.')
 
diff --git a/hiwenet/more_metrics.py b/hiwenet/more_metrics.py
new file mode 100644
index 0000000..4826d5d
--- /dev/null
+++ b/hiwenet/more_metrics.py
@@ -0,0 +1,76 @@
+"""
+Module implementing additional metrics for edge weights.
+
+"""
+
+__all__ = ['diff_medians', 'diff_medians_abs']
+
+import numpy as np
+
+def check_array(array):
+    "Converts to flattened numpy arrays and ensures its not empty."
+
+    if len(array) < 1:
+        raise ValueError('Input array is empty! Must have atleast 1 element.')
+
+    return np.array(array).flatten()
+
+
+def diff_medians(array_one, array_two):
+    """
+    Computes the difference medians between two arrays of values.
+
+    Given arrays will be flattened (to 1D array) regardless of dimension,
+        and any bon-finite/NaN values will be ignored.
+
+    Parameters
+    ----------
+    array_one, array_two : iterable
+        Two arrays of values, possibly of different length.
+
+    Returns
+    -------
+    diff_medians : float
+        scalar measuring the difference in medians, ignoring NaNs/non-finite values.
+
+    Raises
+    ------
+    ValueError
+        If one or more of the arrays are empty.
+
+    """
+
+    array_one = check_array(array_one)
+    array_two = check_array(array_two)
+    diff_medians = np.median(array_one) - np.median(array_two)
+
+    return diff_medians
+
+
+def diff_medians_abs(array_one, array_two):
+    """
+    Computes the absolute difference (symmetric) medians between two arrays of values.
+
+    Given arrays will be flattened (to 1D array) regardless of dimension,
+        and any bon-finite/NaN values will be ignored.
+
+    Parameters
+    ----------
+    array_one, array_two : iterable
+        Two arrays of values, possibly of different length.
+
+    Returns
+    -------
+    diff_medians : float
+        scalar measuring the difference in medians, ignoring NaNs/non-finite values.
+
+    Raises
+    ------
+    ValueError
+        If one or more of the arrays are empty.
+
+    """
+
+    abs_diff_medians = np.abs(diff_medians(array_one, array_two))
+
+    return abs_diff_medians
\ No newline at end of file
diff --git a/hiwenet/hiwenet.py b/hiwenet/pairwise_dist.py
similarity index 96%
rename from hiwenet/hiwenet.py
rename to hiwenet/pairwise_dist.py
index 39b2518..67aa786 100644
--- a/hiwenet/hiwenet.py
+++ b/hiwenet/pairwise_dist.py
@@ -10,6 +10,14 @@ import logging
 import networkx as nx
 import numpy as np
 from os.path import join as pjoin, exists as pexists
+from sys import version_info
+
+if version_info.major==2 and version_info.minor==7:
+    import more_metrics
+elif version_info.major > 2:
+    from hiwenet import more_metrics
+else:
+    raise NotImplementedError('hiwenet supports only 2.7 or 3+. Upgrade to Python 3+ is recommended.')
 
 list_medpy_histogram_metrics = np.array([
     'chebyshev', 'chebyshev_neg', 'chi_square',
@@ -37,7 +45,7 @@ semi_metric_list = [
     'noelle_1', 'noelle_3',
     'correlate_1']
 
-metrics_on_original_features = ['diff_medians', ]
+metrics_on_original_features = ['diff_medians', 'diff_medians_abs']
 
 minimum_num_bins = 5
 
@@ -318,6 +326,8 @@ def extract(features, groups,
         print('All exceptions encountered so far:\n {}'.format('\n'.join(exceptions_list)))
         raise ValueError('Weights for atleast {:.2f}% of edges could not be computed.'.format(error_thresh * 100))
 
+    sys.stdout.write('\n')
+
     if return_networkx_graph:
         if out_weights_path is not None:
             graph.write_graphml(out_weights_path)
@@ -492,16 +502,23 @@ def check_weight_method(weight_method_spec,
         raise TypeError('allow_non_symmetric flag must be boolean')
 
     if isinstance(weight_method_spec, str):
+        weight_method_spec = weight_method_spec.lower()
+
         if weight_method_spec in list_medpy_histogram_metrics:
             from medpy.metric import histogram as medpy_hist_metrics
             weight_func = getattr(medpy_hist_metrics, weight_method_spec)
+            if use_orig_distr:
+                raise ValueError('use_original_distribution must be False when using builtin histogram metrics, '
+                                 'which expect histograms as input.')
+
+        elif weight_method_spec in metrics_on_original_features:
+            weight_func = getattr(more_metrics, weight_method_spec)
+            if not use_orig_distr:
+                raise ValueError('use_original_distribution must be True when using builtin non-histogram metrics, '
+                                 'which expect original feature values in ROI/node as input.')
         else:
             raise NotImplementedError('Chosen histogram distance/metric not implemented or invalid.')
 
-        if use_orig_distr:
-            raise ValueError('use_original_distribution must be False when using builtin histogram metrics, '
-                             'which expect histograms as input.')
-
     elif callable(weight_method_spec):
         # ensure 1) takes two ndarrays
         try:

diff --git a/hiwenet/test_hiwenet.py b/hiwenet/test_hiwenet.py
index e1df71e..afa4ea6 100644
--- a/hiwenet/test_hiwenet.py
+++ b/hiwenet/test_hiwenet.py
@@ -9,8 +9,8 @@ from os.path import join as pjoin, exists as pexists, abspath
 from sys import version_info
 
 if version_info.major==2 and version_info.minor==7:
-    from hiwenet import extract as hiwenet
-    from hiwenet import run_cli as CLI
+    from pairwise_dist import extract as hiwenet
+    from pairwise_dist import run_cli as CLI
 elif version_info.major > 2:
     from hiwenet import extract as hiwenet
     from hiwenet import run_cli as CLI
@@ -72,6 +72,25 @@ def test_dimensions():
     assert len(ew) == num_groups
     assert ew.shape[0] == num_groups and ew.shape[1] == num_groups
 
+def test_more_metrics():
+    ew = hiwenet(features, groups, weight_method='diff_medians',
+                 use_original_distribution=True)
+    assert len(ew) == num_groups
+    assert ew.shape[0] == num_groups and ew.shape[1] == num_groups
+
+    ew_abs = hiwenet(features, groups, weight_method='diff_medians_abs',
+                     use_original_distribution=True)
+    assert np.allclose(np.abs(ew), ew_abs, equal_nan=True)
+
+    with raises(ValueError):
+        ew = hiwenet(features, groups, weight_method='diff_medians',
+                     use_original_distribution=False)
+
+    with raises(ValueError):
+        ew = hiwenet(features, groups,
+                     weight_method='manhattan',
+                     use_original_distribution=True)
+
 def test_too_few_groups():
     features, groups, group_ids, num_groups = make_features(100, 1)
     with raises(ValueError):
@@ -256,6 +275,8 @@ def test_input_callable_on_orig_data():
                      use_original_distribution=True)
 
 # test_directed_nx()
-test_directed_mat()
+# test_directed_mat()
 # test_CLI_output_matches_API()
-# test_input_callable()
\ No newline at end of file
+# test_input_callable()
+
+test_more_metrics()
\ No newline at end of file

Broadening options for weight computation
Using the new feature of arbitrary callable, implement more useful weights

- [ ] such as difference in medians, 
- [ ] correlation, thresholding etc
- [ ] other of interest 
hiwenet/test_hiwenet.py::test_more_metrics hiwenet/test_hiwenet.py::test_too_few_groups hiwenet/test_hiwenet.py::test_too_few_values hiwenet/test_hiwenet.py::test_invalid_trim_perc hiwenet/test_hiwenet.py::test_invalid_weight_method hiwenet/test_hiwenet.py::test_trim_not_too_few_values hiwenet/test_hiwenet.py::test_trim_false_too_few_to_calc_range hiwenet/test_hiwenet.py::test_not_np_arrays hiwenet/test_hiwenet.py::test_CLI_nonexisting_paths hiwenet/test_hiwenet.py::test_CLI_invalid_args hiwenet/test_hiwenet.py::test_CLI_too_few_args hiwenet/test_hiwenet.py::test_input_callable_on_orig_data