CS 3414 Effective Programming Practices Reading: Cheney & Kincaid, (pp. 721-729 ); In-class lecture notes: an example worked out in detail. Computational costs of various mathematical operations. (CPI for MIPS Instruction Categories, pdf) Numerical Math != Math. Common sense tricks in evaluating mathematical expressions. On the right hand side is an equivalent better suited for numerical calculations. MATH =====> NUMERICAL MATH x^2 =====> x*x x^7 =====> x*x*x*x*x*x*x (!) Never pow(x, 7) x/2 =====> 0.5*x Sum(3*x_i) =====> for(i=0; i<100; i++) s+= x[i]; s = s*3.0; // do the sum first, then multiply by a constant // ln(1 + x) ======> x - 0.5*x*x (if x is very small, so x^3 < your precision).
