Chapter 5 has a lot of code with no obvious point

[alanedelman]

Everything from We can make this faster by preallocating the cache vector
to before And let's get the mean of the trajectory for each of the parameters.
hardly speeds anything up so one doesn't pick up the point of anything.
I feel my time was wasted looking at all these codes.

Also all the parallel speed ups that follow are also unimpressive -- downright discouraging.
Chapter 5 has a few good points

• threads having their own stack
• parallel codes can be slow downs
• parallel codes are best on big problems

but otherwise the examples are just horrible sadly.