Learn to tell the difference between scalar, aggregate, and table-returning functions.

Write a C function, void sum_rows( int a*,int sum*,int n) to compute the sum of row elements in a nxn matrix and store the result in vector sum[]. Can this function be optimized by the compiler? If No, why? Rewrite the function to remove the optimization blocker.

Which of the following is the definition of a higher-order function?     func xs = sum (map (^2) xs)     func x = x * 2     func (x,y) = (y,x)     func (x:y:zs) = y     func f [x,y] = [f x, f y]

What are semijoins and how do they perform performance?