Few fixes.

README.md

@@ -51,7 +51,7 @@ Given the pixel row `r`, and the pixel column `c`, one iteration may be written
 for ( dr : -1, 0, 1 )
   for ( dc : -1, 0, 1 )
 	full_u += u[r+dr,c+dc] - u[r,c]
-	full_v += u[r+dr,c+dc] - u[r,c]
+	full_v += v[r+dr,c+dc] - v[r,c]
 
 uvv = u[r,c]*v[r,c]*v[r,c]
 du = DIFFUSION_RATE_U*full_u - uvv + FEED_RATE*(1.0 - u)
@@ -62,7 +62,7 @@ v[r,c] += dv*DT;
 ```
 
 Have a look at the code in the directory `GrayScottSeq/src/main.cpp`.
-Try to run it with the commands below. The value printed at the end
+Understand and run it with the commands below. The value printed at the end
 is juste there as a first check that the code is working as expected,
 when you will try to parallelize it.