Update documentation for comparison-oskar demo

demo/comparison-oskar/README.md

@@ -7,11 +7,13 @@ Comparison plots can be generated by giving the following command in the build d
 ```
 make comparison
 ```
-The number of basefunctions can be set by the environment variable MAX_ORDER, for example
+This will generate a series of image files named basefunction*.png in the \<builddir\>/demo/comparison-oskar directory. The number of basefunctions depends on $L$, the maximum order, and is given by  $N = 2(L+1)^2-2$.
+
+The maximum order can be set by the environment variable MAX_ORDER, for example
 ```
 MAX_ORDER=3 make comparison-oskar
 ```
-computes the basefunctions up to order 3. The number of basefunctions is $2(L+1)^2-2$, where L is the maximum order.
+computes the basefunctions up to order 3, generating 30 image files.
 
 The application of the 'transpose' can be activated by the APPLY_TRANSPOSE environment variable, for example
 ```