Edit example docs

examples/scripts/sparsecode_nn_admm.py

@@ -17,6 +17,9 @@
 where $D$ the dictionary, $\mathbf{y}$ the signal to be represented,
 $\mathbf{x}$ is the sparse representation, and $I(\mathbf{x} \geq 0)$
 is the non-negative indicator.
+
+In this example the problem is solved via ADMM, while Accelerated PGM is
+used in a [companion example](sparsecode_nn_apgm.rst).
 """
 
 import numpy as np

examples/scripts/sparsecode_nn_apgm.py

@@ -17,6 +17,9 @@
 where $D$ the dictionary, $\mathbf{y}$ the signal to be represented,
 $\mathbf{x}$ is the sparse representation, and $I(\mathbf{x} \geq 0)$
 is the non-negative indicator.
+
+In this example the problem is solved via Accelerated PGM, while ADMM is
+used in a [companion example](sparsecode_nn_admm.rst).
 """
 
 import numpy as np