Added comment in the sandbox file.

theano/sandbox/blas_ger.py

@@ -4,6 +4,13 @@ Optimization to specialize gemm -> ger are not written
 
 Scipy implementation is not written
 
+We need to call scipy.linalg.blas.[cf]blas.[sdcz]ger here to don't loose speed again the old Outer op.
+Here is the scipy signature: ger(alpha,x,y,incx=1,incy=1,a=0.0,overwrite_x=1,overwrite_y=1,overwrite_a=0)
+
+http://www.scipy.org/doc/api_docs/SciPy.lib.blas.info.html
+
+
+
 C implementation is not written.
 
 Tests are not written.