Faculty Candidate Arrangement Checklist

Sample exam questions

1. Does the following loop have dependences? Indicate the dependences with arrows, and label the arrows with the dependence attributes that you know.

DO j=lb,ub T = B(j)+D(j) C(j)= T+T2 A(j)=3*A(j)-4*A(j-2) ENDDO

2. Describe three big open issues in optimizing compilers?

3. Give an example code in which in would be advantageous for the compiler to transform it with the privatized reduction trnsformation rather than the expanded reduction transformation. Describe why this is so.

4. Given a cache size of 1MB, what block size would you choose for the following loop:

DO j0=1,jub,block DO k=1,kub DO j=j0, min(j0+block-1,jub) T = B(j,k)+D(j,k) C(j,k)= T+T2 A(j,k)=3*A(j,k)-4*A(j,k-2) ENDDO ENDDO

a) give a formula; define all variables in the formula b) plug in reasonable numerical values for all variables c) as a compiler implementor would you always apply the above blocking transformation for this loop? Explain.