Matplotlib optional

dipy/sims/voxel.py

@@ -250,8 +250,7 @@ def multi_tensor_odf(odf_verts, mf, mevals=None, mevecs=None):
     >>> from dipy.sims.voxel import multi_tensor_odf, all_tensor_evecs
     >>> from dipy.data import get_sphere
     >>> vertices, faces = get_sphere('symmetric724')
-    >>> mevals=np.array(([0.0015, 0.0003, 0.0003],
-                         [0.0015, 0.0003, 0.0003]))
+    >>> mevals=np.array(([0.0015, 0.0003, 0.0003],[0.0015, 0.0003, 0.0003]))
     >>> e0 = np.array([1, 0, 0.])
     >>> e1 = np.array([0., 1, 0])
     >>> mevecs=[all_tensor_evecs(e0), all_tensor_evecs(e1)]

dipy/viz/__init__.py

@@ -1,4 +1,33 @@
 # Init file for visualization package
 
-from ._show_odfs import show_odfs
-from projections import *
+
+# We make the visualization requirements (mayavi, matplotlib) optional
+# imports:
+
+try: 
+    # Mayavi appears in many guises:
+    try:
+        from enthought.mayavi import mlab
+    except ImportError:
+        from mayavi import mlab
+    has_mayavi = True
+except ImportError:
+    e_s = "You do not have Mayavi installed. Some visualization functions"
+    e_s += " might not work."
+    print(e_s)
+    has_mayavi = False
+
+try:
+    import matplotlib
+    has_mpl = True
+except ImportError:
+    e_s = "You do not have Matplotlib installed. Some visualization functions"
+    e_s += " might not work for you."
+    print(e_s)
+    has_mpl = False
+
+if has_mayavi:
+    from ._show_odfs import show_odfs
+
+if has_mpl:
+    from projections import *

dipy/viz/projections.py

@@ -8,14 +8,25 @@
 import numpy as np
 import scipy.interpolate as interp
 
-import matplotlib
-import matplotlib.pyplot as plt
-import matplotlib.tri as tri
+try:
+    import matplotlib
+    import matplotlib.pyplot as plt
+    import matplotlib.tri as tri
+    has_mpl = True
+    hot = matplotlib.cm.hot
+except ImportError:
+    e_s = "You do not have Matplotlib installed. Some visualization functions"
+    e_s += " might not work for you."
+    print(e_s)
+    has_mpl=False
+    hot = None
+    plt = None
 
 import dipy.core.geometry as geo
 
+
 def sph_project(vertices, val, ax=None, vmin=None, vmax=None,
-		cmap=matplotlib.cm.hot, cbar=True, triang=False):
+                cmap=hot, cbar=True, triang=False):
 
     """Draw a signal on a 2D projection of the sphere.
 
@@ -49,11 +60,11 @@ def sph_project(vertices, val, ax=None, vmin=None, vmax=None,
     --------
     >>> from dipy.data import get_sphere
     >>> verts,faces=get_sphere('symmetric724')
-    >>> sph_project(verts,np.random.rand(len(verts)))
+    >>> ax = sph_project(verts,np.random.rand(len(verts)))
 
     """
-    if ax is None:
-        _, ax = plt.subplots(1)
+    if ax is None and plt is not None:
+            _, ax = plt.subplots(1)
     fig = ax.get_figure()
 
     x = vertices[:, 0]
@@ -75,22 +86,22 @@ def sph_project(vertices, val, ax=None, vmin=None, vmax=None,
     r[r>1]=1
 
     if triang:
-	triang = tri.Triangulation(x, y)
-	ax.tripcolor(triang, r, cmap=cmap)
+        triang = tri.Triangulation(x, y)
+        ax.tripcolor(triang, r, cmap=cmap)
     else:
-	cmap_data = cmap._segmentdata
-	red_interp, blue_interp, green_interp = (
-		interp.interp1d(np.array(cmap_data[gun])[:,0],
-				np.array(cmap_data[gun])[:,1]) for gun in
-		                ['red', 'blue','green'])
-
-
-	for this_x, this_y, this_r in zip(x,y,r):
-	    red = red_interp(this_r)
-	    blue = blue_interp(this_r)
-	    green = green_interp(this_r)
-	    ax.plot(this_x, this_y, 'o',
-		    c=[red.item(), green.item(), blue.item()])
+        cmap_data = cmap._segmentdata
+        red_interp, blue_interp, green_interp = (
+                interp.interp1d(np.array(cmap_data[gun])[:,0],
+                                np.array(cmap_data[gun])[:,1]) for gun in
+                                ['red', 'blue','green'])
+
+
+        for this_x, this_y, this_r in zip(x,y,r):
+            red = red_interp(this_r)
+            blue = blue_interp(this_r)
+            green = green_interp(this_r)
+            ax.plot(this_x, this_y, 'o',
+                    c=[red.item(), green.item(), blue.item()])
 
 
     ax.set_aspect('equal')