johneddy101@comcast.net wrote:
Hello, I realize that this library is not yet part of the boost distribution but I am using it and have come accross an issue. I am concerned that the logic in the various check functions may be flawed. Take for example the check_uniform function. The logic is as follows: if lower Ok && upper Ok && lower < upper return true else raise error stating that lower must be less than upper return false end if
The functions used to determine if lower and upper are ok will raise errors if appropriate. If the policy is such that raising an error does not cause a throw, then control will return to the check_uniform method with an indication that lower or upper is not ok and we will enter the else block. Herein lies the problem. Consider the following scenario: creating a uniform distribution with: lower = 0.0 upper = postitive infinity Check upper will fail and send a message about the infinity. Enter the else block. A message will be raised that states that the lower parameter is not less than the upper. This is my concern. I believe the second message is unnecessary and potentially incorrect/misleading. Perhaps logic like shown below would be more appropriate: if lower not Ok || upper not Ok then return false else if lower >= upper raise error stating that lower must be less than upper return false else return true end if
Yep, will change as suggested: note however you can only actually observe the domain_error handler being called twice (with different messages) if you are using a user-defined error handler *and* that handler doesn't throw an exception. Paul, I think this one was one of yours? Are we likely to need to give the other distros a once-over to check we don't do this elsewhere as well? Thanks for spotting this, John.