Remove unused Variables from LayoutGrid

While the above comment claims that these variables are useful, they are
not added to the solver nor added to any constraints, so they cannot
contain any useful information.

They are only really used for the `__repr__`, which can be changed to
the actually-used Variables instead.

Author: QuLogic

lib/matplotlib/_layoutgrid.py

@@ -77,14 +77,8 @@ def __init__(self, parent=None, parent_pos=(0, 0),
 
         sol = self.solver
 
-        # These are redundant, but make life easier if
-        # we define them all.  All that is really
-        # needed is left/right, margin['left'], and margin['right']
-        self.widths = [Variable(f'{sn}widths[{i}]') for i in range(ncols)]
         self.lefts = [Variable(f'{sn}lefts[{i}]') for i in range(ncols)]
         self.rights = [Variable(f'{sn}rights[{i}]') for i in range(ncols)]
-        self.inner_widths = [Variable(f'{sn}inner_widths[{i}]')
-                             for i in range(ncols)]
         for todo in ['left', 'right', 'leftcb', 'rightcb']:
             self.margins[todo] = [Variable(f'{sn}margins[{todo}][{i}]')
                                   for i in range(ncols)]
@@ -95,9 +89,6 @@ def __init__(self, parent=None, parent_pos=(0, 0),
             self.margins[todo] = np.empty((nrows), dtype=object)
             self.margin_vals[todo] = np.zeros(nrows)
 
-        self.heights = [Variable(f'{sn}heights[{i}]') for i in range(nrows)]
-        self.inner_heights = [Variable(f'{sn}inner_heights[{i}]')
-                              for i in range(nrows)]
         self.bottoms = [Variable(f'{sn}bottoms[{i}]') for i in range(nrows)]
         self.tops = [Variable(f'{sn}tops[{i}]') for i in range(nrows)]
         for todo in ['bottom', 'top', 'bottomcb', 'topcb']:
@@ -119,14 +110,14 @@ def __repr__(self):
         for i in range(self.nrows):
             for j in range(self.ncols):
                 str += f'{i}, {j}: '\
-                       f'L({self.lefts[j].value():1.3f}, ' \
+                       f'L{self.lefts[j].value():1.3f}, ' \
                        f'B{self.bottoms[i].value():1.3f}, ' \
-                       f'W{self.widths[j].value():1.3f}, ' \
-                       f'H{self.heights[i].value():1.3f}, ' \
-                       f'innerW{self.inner_widths[j].value():1.3f}, ' \
-                       f'innerH{self.inner_heights[i].value():1.3f}, ' \
+                       f'R{self.rights[j].value():1.3f}, ' \
+                       f'T{self.tops[i].value():1.3f}, ' \
                        f'ML{self.margins["left"][j].value():1.3f}, ' \
-                       f'MR{self.margins["right"][j].value():1.3f}, \n'
+                       f'MR{self.margins["right"][j].value():1.3f}, ' \
+                       f'MB{self.margins["bottom"][i].value():1.3f}, ' \
+                       f'MT{self.margins["top"][i].value():1.3f}, \n'
         return str
 
     def reset_margins(self):