4 ms·

I concentrated in optimization and numerical analysis for my undergrad degree in Math, and I'm still surprised on a regular basis how many programmers out there

I concentrated in optimization and numerical analysis for my undergrad degree in Math, and I'm still surprised on a regular basis how many programmers out there don't know about the inaccuracies and errors that come out of floating-point representations.

pmorici 17y ago
Are you really that surprised. Crappy programmers abound and many introductory programming classes have students write programs to calculate monetary things using floating point so it's no small wonder many people think it's ok.
jwr 17y ago
My thoughts exactly. Tom Christiansen brings these things up as if they were a huge surprise, but they aren't, or at least shouldn't be. To put it another way, it isn't Apple doing something wrong. If your code depends on rounding errors in FP representations, your code is buggy. That's also why good numerical algorithms are hard to design. You need to worry about losing precision. As a simple example, if you calculate (a-b)c and a is almost equal to b, you're much better off doing ac-b*c. These tricks are important.
brettnak 17y ago
As did, I. I am a professional programmer now and didn't go through the CS school ( To all sophomores out there: We do exist. ) Do they really not teach this sort of thing in a formal CS school?
- wtallis 17y ago
  Most CS undergraduate programs in the US suck enough these days that numerical analysis isn't taught at the undergrad level. For example, at my school, undergraduates get to choose between the automata/grammars/computability class and a "numerical methods" class that is really watered down. There is a two-semester undergraduate numerical analysis class, but as I recall it can't count toward your degree except as a general elective. To get numerical analysis to count as a CS elective, you have to take the graduate level class.

4 ms·

I concentrated in optimization and numerical analysis for my undergrad degree in Math, and I'm still surprised on a regular basis how many programmers out there

by profquail 17y ago

pmorici 17y ago
Are you really that surprised. Crappy programmers abound and many introductory programming classes have students write programs to calculate monetary things using floating point so it's no small wonder many people think it's ok.
jwr 17y ago
My thoughts exactly. Tom Christiansen brings these things up as if they were a huge surprise, but they aren't, or at least shouldn't be. To put it another way, it isn't Apple doing something wrong. If your code depends on rounding errors in FP representations, your code is buggy. That's also why good numerical algorithms are hard to design. You need to worry about losing precision. As a simple example, if you calculate (a-b)c and a is almost equal to b, you're much better off doing ac-b*c. These tricks are important.
brettnak 17y ago
As did, I. I am a professional programmer now and didn't go through the CS school ( To all sophomores out there: We do exist. ) Do they really not teach this sort of thing in a formal CS school?
- wtallis 17y ago
  Most CS undergraduate programs in the US suck enough these days that numerical analysis isn't taught at the undergrad level. For example, at my school, undergraduates get to choose between the automata/grammars/computability class and a "numerical methods" class that is really watered down. There is a two-semester undergraduate numerical analysis class, but as I recall it can't count toward your degree except as a general elective. To get numerical analysis to count as a CS elective, you have to take the graduate level class.