Ticket #1877: trac_1877.patch

a/sage/plot/plot3d/parametric_plot3d.py

@@ -336 +336 @@
-        sage: fz = -u + (2*0.84*cosh(0.4*u)*sinh(0.4*u))/(0.4*((sqrt(0.84)*cosh(0.4*u))^2 + (0.4*sin(sqrt(0.84)*v))^2))
-        sage: parametric_plot3d([fx, fy, fz], (u, -13.2, 13.2), (v, -37.4, 37.4), plot_points = [90,90], frame=False, color="green")
-
+    TESTS:
+    
+        sage: u, v = var('u,v')
+        sage: plot3d(u^2-v^2, (u, -1, 1), (u, -1, 1))
+        Traceback (most recent call last):
+        ...
+        ValueError: Plot variables should be distinct, but both are u.
-    """
-    # TODO:
-    #   * Surface -- behavior of functions not defined everywhere -- see note above
@@ -366 +373 @@
-            plot_points = 75
-        G = parametric_plot3d_curve(f, urange, plot_points, **kwds)
-    else:
+        if urange[0] is vrange[0]:
+            raise ValueError, "Plot variables should be distinct, but both are %s."%urange[0]        
+
-        if plot_points == "automatic":
-            plot_points = [40,40]
-        G = parametric_plot3d_surface(f, urange, vrange, plot_points, **kwds)

a/sage/plot/plot3d/plot3d.py

@@ -128 +128 @@
-    Hill and valley (flat surface with a bump and a dent):
-        sage: x, y = var('x y')
-        sage: plot3d( 4*x*exp(-x^2-y^2), (x,-2,2), (y,-2,2))
+
+    TESTS:
+    Listing the same plot variable twice gives an error.
+        sage: x, y = var('x y')
+        sage: plot3d( 4*x*exp(-x^2-y^2), (x,-2,2), (x,-2,2))
+        Traceback (most recent call last):
+        ...
+        ValueError: Plot variables should be distinct, but both are x.
-    """
-    if len(urange) == 2:
-        try:
@@ -140 +148 @@
-    else:
-        u = urange[0]
-        v = vrange[0]
+        if u is v:
+            raise ValueError, "Plot variables should be distinct, but both are %s."%u   
+        
-        w = (u, v, f)
-
-    if adaptive: