Back: Errors Forward: Simple debugging   FastBack: Shell commands Up: Errors FastForward: Arrays         Top: Yorick Contents: Table of Contents Index: Concept Index About: About this document Runtime errors

Runtime errors in Yorick are often simple typos, like syntax errors:

> theta = span(0,2*pi,200)
 > wave = sin(thta)*exp(-0.5*theta)
 ERROR (*main*) expecting numeric argument
 WARNING source code unavailable (try dbdis function)
 now at pc= 1 (of 23), failed at pc= 5
  To enter debug mode, type <RETURN> now (then dbexit to get out)

Many errors of this sort would be detected as syntax errors if you had to declare Yorick variables. Yorick's free-and-easy attitude toward declaration of variables is particularly annoying when the offending statement is in a conditional branch which is very rarely executed. When a bug like that ambushes you, be philosophical: Minutely declared languages will just ambush you in more subtle ways.

Other runtime errors are more interesting; often such a bug will teach you about the algorithm or even about the physical problem:

> #include "damped.i"
 > theta = span(0, 6*pi, 300)
 > amplitude = damped_wave(theta, 0.25)
 ERROR (damped_wave) math library exception handler called
   LINE: 19  FILE: /home/icf/munro/damped.i
  To enter debug mode, type <RETURN> now (then dbexit to get out)

What is an oscillator with a Q of less than one half? Maybe you don't care about the so-called overdamped case -- you really wanted Q to be 2.5, not 0.25. On the other hand, maybe you need to modify the damped_wave function to handle the overdamped case.