Fix flake8 warnings

mdsa/algorithms/nystrom.py

@@ -40,15 +40,15 @@
 
         /  E  |  F \
     D = |-----|----|
-        \ F.t |  G /
+        \\ F.t |  G /
 
 
 The correspondong association matrix or centered inner-product
 matrix K is:
 
         /  A  |  B \
     K = |-----|----|
-        \ B.t |  C /
+        \\ B.t |  C /
 
 where A and B are computed as follows
 

mdsa/algorithms/scmds.py

@@ -220,8 +220,8 @@ def affine_mapping(self, matrix_x, matrix_y):
 
         Affine mapping function:
         Y = UX + kron(b,ones(1,n)), UU' = I
-        X = [x_1, x_2, ... , x_n]; x_j \in R^m
-        Y = [y_1, y_2, ... , y_n]; y_j \in R^m
+        X = [x_1, x_2, ... , x_n]; x_j \\in R^m
+        Y = [y_1, y_2, ... , y_n]; y_j \\in R^m
 
         From Tzeng 2008:
         `The projection of xi,2 from q2 dimension to q1 dimension

mdsa/pcoa.py

@@ -64,7 +64,7 @@ def pcoa(distance_matrix, algorithm, num_dimensions_out=10):
        If the distance is not euclidean (for example if it is a
        semimetric and the triangle inequality doesn't hold),
        negative eigenvalues can appear. There are different ways
-       to deal with that problem (see Legendre & Legendre 1998, \S
+       to deal with that problem (see Legendre & Legendre 1998, \\S
        9.2.3), but none are currently implemented here.
        However, a warning is raised whenever negative eigenvalues
        appear, allowing the user to decide if they can be safely