april 23
P and NP
Discussed last week. Questions? Comments?
- define CNF for satisfiability problem.
- wikipedia articles assigned for homework
Numerical Precision
Vocabulary to understand
- single and double precision (see for example wikipedia: double precision )
- absolute vs relative error
- overflow and underflow
- subtractive error (see pg 407 example)
- instability (property of algorithm)
- ill-conditioned (property of problem)
Text discussion of complications in implementing quadratic formula well:
Newton's method to find x = sqrt(y) :
x[0] = (1+y)/2
x[n+1] = (1/2) ( x[n] + y/x[n] )
- how to avoid subtractive error?
Special functions
