Chapter 5, Problem 5.18HW

Program Plan Intro

Given C Code:

double poly(double a[], double x, long degree)

{

long i;

double result = a[0];

double xpwr = x;

for (i = 1; i <= degree; i++)

{

result += a[i] * xpwr;

xpwr = x * xpwr;

}

return result;

}

double polyh(double a[], double x, long degree)

{

long i;

double result = a[degree];

for(i=degree-1; i>=0; i--)

result = a[i] + x*result;

return result;

}

Cycles per element (CPE):

• The CPE denotes performance of program that helps in improving code.
• It helps to understand detailed level loop performance for an iterative program.
• It is appropriate for programs that use a repetitive computation.
• The processor’s activity sequencing is controlled by a clock that provides regular signal of some frequency.

Loop unrolling:

• It denotes a program transformation that would reduce count of iterations for a loop.
• It increases count of elements computed in each iteration.
• It reduces number of operations that is not dependent to program directly.
• It reduces count of operations in critical paths of overall computations.