Adding a general interface for N-dimensional gridded data

holoviews/core/dimension.py

@@ -754,7 +754,7 @@ def select(self, selection_specs=None, **kwargs):
         return selection
 
 
-    def dimension_values(self, dimension, unique=False):
+    def dimension_values(self, dimension, expanded=True, flat=True):
         """
         Returns the values along the specified dimension. This method
         must be implemented for all Dimensioned type.

holoviews/core/element.py

@@ -482,15 +482,16 @@ def aggregate(self, dimensions, function, **kwargs):
         return self.clone(rows, kdims=grouped.kdims)
 
 
-    def dimension_values(self, dim, unique=False):
+    def dimension_values(self, dim, expanded=True, flat=True):
         dim = self.get_dimension(dim, strict=True)
         value_dims = self.dimensions('value', label=True)
         if dim.name in value_dims:
             index = value_dims.index(dim.name)
             vals = np.array([v[index] for v in self.data.values()])
-            return unique_array(vals) if unique else vals
+            return vals if expanded else unique_array(vals)
         else:
-            return NdMapping.dimension_values(self, dim.name, unique)
+            return NdMapping.dimension_values(self, dim.name,
+                                              expanded, flat)
 
 
     def values(self):

holoviews/core/layout.py

@@ -126,9 +126,9 @@ def get(self, key, default=None):
         return self.data[key] if key in self.data else default
 
 
-    def dimension_values(self, dimension, unique=False):
+    def dimension_values(self, dimension, expanded=True, flat=True):
         dimension = self.get_dimension(dimension, strict=True).name
-        return self.main.dimension_values(dimension, unique)
+        return self.main.dimension_values(dimension, expanded, flat)
 
 
     def __getitem__(self, key):
@@ -433,17 +433,18 @@ def clone(self, *args, **overrides):
         return clone
 
 
-    def dimension_values(self, dimension, unique=False):
+    def dimension_values(self, dimension, expanded=True, flat=True):
         "Returns the values along the specified dimension."
         dimension = self.get_dimension(dimension, strict=True).name
         all_dims = self.traverse(lambda x: [d.name for d in x.dimensions()])
         if dimension in chain.from_iterable(all_dims):
             values = [el.dimension_values(dimension) for el in self
                       if dimension in el.dimensions(label=True)]
             vals = np.concatenate(values)
-            return unique_array(vals) if unique else vals
+            return vals if expanded else unique_array(vals)
         else:
-            return super(Layout, self).dimension_values(dimension, unique)
+            return super(Layout, self).dimension_values(dimension,
+                                                        expanded, flat)
 
 
     def cols(self, ncols):

holoviews/core/ndmapping.py

@@ -343,7 +343,7 @@ def drop_dimension(self, dimensions):
                           kdims=dims)
 
 
-    def dimension_values(self, dimension, unique=False):
+    def dimension_values(self, dimension, expanded=True, flat=True):
         "Returns the values along the specified dimension."
         dimension = self.get_dimension(dimension, strict=True).name
         if dimension in self.kdims:
@@ -352,9 +352,9 @@ def dimension_values(self, dimension, unique=False):
             values = [el.dimension_values(dimension) for el in self
                       if dimension in el.dimensions()]
             vals = np.concatenate(values)
-            return util.unique_array(vals) if unique else vals
+            return vals if expanded else util.unique_array(vals)
         else:
-            return super(MultiDimensionalMapping, self).dimension_values(dimension, unique)
+            return super(MultiDimensionalMapping, self).dimension_values(dimension, expanded, flat)
 
 
     def reindex(self, kdims=[], force=False):

holoviews/core/overlay.py

@@ -65,20 +65,20 @@ def hist(self, index=0, adjoin=True, dimension=None, **kwargs):
         return layout
 
 
-    def dimension_values(self, dimension, unique=False):
+    def dimension_values(self, dimension, expanded=True, flat=True):
         values = []
         found = False
         for el in self:
             if dimension in el.dimensions(label=True):
                 values.append(el.dimension_values(dimension))
                 found = True
         if not found:
-            return super(CompositeOverlay, self).dimension_values(dimension, unique)
+            return super(CompositeOverlay, self).dimension_values(dimension, expanded, flat)
         values = [v for v in values if v is not None and len(v)]
         if not values:
             return np.array()
         vals = np.concatenate(values)
-        return unique_array(vals) if unique else vals
+        return vals if expanded else unique_array(vals)
 
 
 class Overlay(Layout, CompositeOverlay):

holoviews/core/util.py

@@ -4,6 +4,7 @@
 import string, fnmatch
 import unicodedata
 from collections import defaultdict
+from functools import reduce
 
 import numpy as np
 import param
@@ -861,3 +862,16 @@ def groupby_python(self_or_cls, ndmapping, dimensions, container_type,
         return container_type(groups, kdims=dimensions)
 
 
+def cartesian_product(arrays):
+    """
+    Computes the cartesian product of a list of arrays.
+    """
+    broadcastable = np.ix_(*arrays)
+    broadcasted = np.broadcast_arrays(*broadcastable)
+    rows, cols = reduce(np.multiply, broadcasted[0].shape), len(broadcasted)
+    out = np.empty(rows * cols, dtype=broadcasted[0].dtype)
+    start, end = 0, rows
+    for a in broadcasted:
+        out[start:end] = a.reshape(-1)
+        start, end = end, end + rows
+    return out.reshape(cols, rows).T

holoviews/element/raster.py

@@ -129,7 +129,7 @@ def sample(self, samples=[], **sample_values):
             sample[sample_ind] = self._coord2matrix(coord_fn(sample_coord))[abs(sample_ind-1)]
 
             # Sample data
-            x_vals = self.dimension_values(other_dimension[0].name, unique=True)
+            x_vals = self.dimension_values(other_dimension[0].name, False)
             ydata = self._zdata[sample[::-1]]
             if hasattr(self, 'bounds') and sample_ind == 0: ydata = ydata[::-1]
             data = list(zip(x_vals, ydata))
@@ -154,7 +154,7 @@ def reduce(self, dimensions=None, function=None, **reduce_map):
             dimension = dims[0]
             other_dimension = [d for d in self.kdims if d.name != dimension]
             oidx = self.get_dimension_index(other_dimension[0])
-            x_vals = self.dimension_values(other_dimension[0].name, unique=True)
+            x_vals = self.dimension_values(other_dimension[0].name, False)
             reduced = function(self._zdata, axis=oidx)
             data = zip(x_vals, reduced if not oidx else reduced[::-1])
             params = dict(dict(self.get_param_values(onlychanged=True)),
@@ -164,18 +164,18 @@ def reduce(self, dimensions=None, function=None, **reduce_map):
             return Table(data, **params)
 
 
-    def dimension_values(self, dim, unique=False):
+    def dimension_values(self, dim, expanded=True, flat=True):
         """
         The set of samples available along a particular dimension.
         """
         dim_idx = self.get_dimension_index(dim)
-        if unique and dim_idx == 0:
+        if not expanded and dim_idx == 0:
             return np.array(range(self.data.shape[1]))
-        elif unique and dim_idx == 1:
+        elif not expanded and dim_idx == 1:
             return np.array(range(self.data.shape[0]))
         elif dim_idx in [0, 1]:
-            D1, D2 = np.mgrid[0:self.data.shape[1], 0:self.data.shape[0]]
-            return D1.flatten() if dim_idx == 0 else D2.flatten()
+            values = np.mgrid[0:self.data.shape[1], 0:self.data.shape[0]][dim_idx]
+            return values.flatten() if flat else values
         elif dim_idx == 2:
             return toarray(self.data.T).flatten()
         else:
@@ -338,20 +338,20 @@ def range(self, dimension):
         super(QuadMesh, self).range(dimension)
 
 
-    def dimension_values(self, dimension, unique=False):
+    def dimension_values(self, dimension, expanded=True, flat=True):
         idx = self.get_dimension_index(dimension)
         data = self.data[idx]
         if idx in [0, 1]:
             if not self._grid:
                 return data.flatten()
-            odim = 1 if unique else self.data[2].shape[idx]
+            odim = self.data[2].shape[idx] if expanded else 1
             vals = np.tile(np.convolve(data, np.ones((2,))/2, mode='valid'), odim)
             if idx:
                 return np.sort(vals)
             else:
                 return vals
         elif idx == 2:
-            return data.flatten()
+            return data.flatten() if flat else data
         else:
             return super(QuadMesh, self).dimension_values(idx)
 
@@ -388,8 +388,8 @@ def __init__(self, data, extents=None, **params):
 
 
     def _compute_raster(self):
-        d1keys = self.dimension_values(0, True)
-        d2keys = self.dimension_values(1, True)
+        d1keys = self.dimension_values(0, False)
+        d2keys = self.dimension_values(1, False)
         coords = [(d1, d2, np.NaN) for d1 in d1keys for d2 in d2keys]
         dtype = 'dataframe' if pd else 'dictionary'
         dense_data = Columns(coords, kdims=self.kdims, vdims=self.vdims, datatype=[dtype])
@@ -438,8 +438,8 @@ def __setstate__(self, state):
         super(HeatMap, self).__setstate__(state)
 
     def dense_keys(self):
-        d1keys = self.dimension_values(0, True)
-        d2keys = self.dimension_values(1, True)
+        d1keys = self.dimension_values(0, False)
+        d2keys = self.dimension_values(1, False)
         return list(zip(*[(d1, d2) for d1 in d1keys for d2 in d2keys]))
 
 
@@ -603,7 +603,7 @@ def _coord2matrix(self, coord):
         return self.sheet2matrixidx(*coord)
 
 
-    def dimension_values(self, dim, unique=False):
+    def dimension_values(self, dim, expanded=True, flat=True):
         """
         The set of samples available along a particular dimension.
         """
@@ -615,13 +615,16 @@ def dimension_values(self, dim, unique=False):
             d2_half_unit = (t - b)/dim2/2.
             d1lin = np.linspace(l+d1_half_unit, r-d1_half_unit, dim1)
             d2lin = np.linspace(b+d2_half_unit, t-d2_half_unit, dim2)
-            if unique:
-                return d2lin if dim_idx else d1lin
+            if expanded:
+                values = np.meshgrid(d2lin, d1lin)[abs(dim_idx-1)]
+                return values.flatten() if flat else values
             else:
-                Y, X = np.meshgrid(d2lin, d1lin)
-                return Y.flatten() if dim_idx else X.flatten()
+                return d2lin if dim_idx else d1lin
         elif dim_idx == 2:
-            return np.flipud(self.data).T.flatten()
+            # Raster arrays are stored with different orientation
+            # than expanded column format, reorient before expanding
+            data = np.flipud(self.data).T
+            return data.flatten() if flat else data
         else:
             super(Image, self).dimension_values(dim)
 
@@ -703,14 +706,15 @@ def load_image(cls, filename, height=1, array=False, bounds=None, bare=False, **
         return rgb
 
 
-    def dimension_values(self, dim, unique=False):
+    def dimension_values(self, dim, expanded=True, flat=True):
         """
         The set of samples available along a particular dimension.
         """
         dim_idx = self.get_dimension_index(dim)
         if self.ndims <= dim_idx < len(self.dimensions()):
-            return np.flipud(self.data[:,:,dim_idx-self.ndims]).T.flatten()
-        return super(RGB, self).dimension_values(dim, unique=True)
+            data = np.flipud(self.data[:,:,dim_idx-self.ndims]).T
+            return data.flatten() if flat else data
+        return super(RGB, self).dimension_values(dim, expanded, flat)
 
 
     def __init__(self, data, **params):

holoviews/element/tabular.py

@@ -71,7 +71,7 @@ def collapse_data(cls, data, function, **kwargs):
         return OrderedDict(zip(data[0].keys(), function(groups, axis=-1, **kwargs)))
 
 
-    def dimension_values(self, dimension):
+    def dimension_values(self, dimension, expanded=True, flat=True):
         dimension = self.get_dimension(dimension, strict=True).name
         if dimension in self.dimensions('value', label=True):
             return np.array([self.data.get(dimension, np.NaN)])

holoviews/operation/element.py

@@ -428,8 +428,8 @@ def _process(self, element, key=None):
             data = [element.data]
 
         elif isinstance(element, QuadMesh):
-            data = (element.dimension_values(0, True),
-                    element.dimension_values(1, True),
+            data = (element.dimension_values(0, False),
+                    element.dimension_values(1, False),
                     element.data[2])
         contour_set = contour_fn(*data, extent=extent,
                                  levels=self.p.levels)

holoviews/plotting/mpl/raster.py

@@ -111,7 +111,7 @@ def _annotate_plot(self, ax, annotations):
     def _annotate_values(self, element):
         val_dim = element.vdims[0]
         vals = np.rot90(element.raster, 3).flatten()
-        d1uniq, d2uniq = [np.unique(element.dimension_values(i)) for i in range(2)]
+        d1uniq, d2uniq = [element.dimension_values(i, False) for i in range(2)]
         num_x, num_y = len(d1uniq), len(d2uniq)
         xstep, ystep = 1.0/num_x, 1.0/num_y
         xpos = np.linspace(xstep/2., 1.0-xstep/2., num_x)
@@ -127,7 +127,7 @@ def _annotate_values(self, element):
 
     def _compute_ticks(self, element, ranges):
         xdim, ydim = element.kdims
-        dim1_keys, dim2_keys = [element.dimension_values(i, True)
+        dim1_keys, dim2_keys = [element.dimension_values(i, False)
                                 for i in range(2)]
         num_x, num_y = len(dim1_keys), len(dim2_keys)
         x0, y0, x1, y1 = element.extents

tests/testcolumns.py

@@ -176,8 +176,8 @@ def test_columns_dataframe_init_ht(self):
 
     # Test literal formats
 
-    def test_columns_uniq_dimvals_ht(self):
-        self.assertEqual(self.table.dimension_values('Gender', unique=True),
+    def test_columns_expanded_dimvals_ht(self):
+        self.assertEqual(self.table.dimension_values('Gender', expanded=False),
                          np.array(['M', 'F']))
 
     def test_columns_implicit_indexing_init(self):
@@ -399,3 +399,79 @@ def test_columns_double_zip_init(self):
                           kdims=self.kdims, vdims=self.vdims)
         self.assertTrue(isinstance(columns.data, NdElement))
 
+
+class GridColumnsTest(HomogeneousColumnTypes, ComparisonTestCase):
+    """
+    Test of the NdColumns interface (mostly for backwards compatibility)
+    """
+
+    def setUp(self):
+        self.restore_datatype = Columns.datatype
+        Columns.datatype = ['grid']
+        self.data_instance_type = dict
+        self.init_data()
+
+    def init_data(self):
+        self.xs = range(11)
+        self.xs_2 = [el**2 for el in self.xs]
+
+        self.y_ints = [i*2 for i in range(11)]
+        self.columns_hm = Columns((self.xs, self.y_ints),
+                                  kdims=['x'], vdims=['y'])
+
+    def test_columns_array_init_hm(self):
+        "Tests support for arrays (homogeneous)"
+        exception = "None of the available storage backends "\
+         "were able to support the supplied data format."
+        with self.assertRaisesRegexp(Exception, exception):
+            Columns(np.column_stack([self.xs, self.xs_2]),
+                    kdims=['x'], vdims=['x2'])
+
+    def test_columns_dataframe_init_hm(self):
+        "Tests support for homogeneous DataFrames"
+        if pd is None:
+            raise SkipTest("Pandas not available")
+        exception = "None of the available storage backends "\
+         "were able to support the supplied data format."
+        with self.assertRaisesRegexp(Exception, exception):
+            Columns(pd.DataFrame({'x':self.xs, 'x2':self.xs_2}),
+                    kdims=['x'], vdims=['x2'])
+
+    def test_columns_ndelement_init_hm(self):
+        "Tests support for homogeneous NdElement (backwards compatibility)"
+        exception = "None of the available storage backends "\
+         "were able to support the supplied data format."
+        with self.assertRaisesRegexp(Exception, exception):
+            Columns(NdElement(zip(self.xs, self.xs_2),
+                              kdims=['x'], vdims=['x2']))
+
+    def test_columns_2D_aggregate_partial_hm(self):
+        array = np.random.rand(11, 11)
+        columns = Columns({'x':self.xs, 'y':self.y_ints, 'z': array},
+                          kdims=['x', 'y'], vdims=['z'])
+        self.assertEqual(columns.aggregate(['x'], np.mean),
+                         Columns({'x':self.xs, 'z': np.mean(array, axis=1)},
+                                 kdims=['x'], vdims=['z']))
+
+    def test_columns_2D_reduce_hm(self):
+        array = np.random.rand(11, 11)
+        columns = Columns({'x':self.xs, 'y':self.y_ints, 'z': array},
+                          kdims=['x', 'y'], vdims=['z'])
+        self.assertEqual(np.array(columns.reduce(['x', 'y'], np.mean)),
+                         np.mean(array))
+
+    def test_columns_add_dimensions_value_hm(self):
+        with self.assertRaisesRegexp(Exception, 'Cannot add key dimension to a dense representation.'):
+            self.columns_hm.add_dimension('z', 1, 0)
+
+    def test_columns_add_dimensions_values_hm(self):
+        table =  self.columns_hm.add_dimension('z', 1, range(1,12), vdim=True)
+        self.assertEqual(table.vdims[1], 'z')
+        self.compare_arrays(table.dimension_values('z'), np.array(list(range(1,12))))
+
+    def test_columns_sort_vdim_hm(self):
+        exception = ('Compressed format cannot be sorted, either instantiate '
+                     'in the desired order or use the expanded format.')
+        with self.assertRaisesRegexp(Exception, exception):
+            self.columns_hm.sort('y')
+