On Sat, 05 Jan 2013 11:47:09 -0600, David C. Ullrich <firstname.lastname@example.org> wrote:
>On Fri, 04 Jan 2013 15:08:19 -0800, Jennifer Murphy ><JenMurphy@jm.invalid> wrote: > >>I have a little Word macro that will assign a random color from the >>entire 16M color palette to each letter in a text string. It does this >>by selecting a random number on (0,255) for each of the RGB colors. >> >>The VBA code is: >> >> Sub MyRandCharColors() >> Dim oChr As Range >> Dim sngR As Single, sngG As Single, sngB As Single >> Randomize > >A comment that has nothing to do with your question: >That call to Randomize is wrong!
It may not be optimal, but I don't think it's wrong.
>It's a common thing, people calling Randomize, or the >equivalent in another language, in the body of a >function like this, thinking that the more calls to >Randomize the better.
How do you know what "people", or more specifically I, think or why the call was put where it was? A little presumptuous, don't you think? Also a little condescending.
In my case, you are incorrect.
>But in fact you should call >Randomize only _once_ in the course of the application! >Call Randomize in whatever routine VBA has for >initializing things (FormCreate or something). > >You think calling Randomize over and over is >making things more random,
There you go again. How do you know what I think? I do not think that calling Randomize more than once will somehow (magically) make things more random.
>but it actually >makes things _less_ random. The story: >Randomize sets some "seed" based on the >system clock. Once that seed is set, repeated >calls to Rnd return a sequence of quasi-random >numbers, starting with he seed.
Yes, I knew that, as, I imagine, do most "people".
>Luckily VBA is slow. But the same principle >applies: Imagine this is some fast compiled >language. You call Randomize, the seed gets >set. The next time you call MyRandCharColors, >the clock hasn't ticked yet, so you reset >the seed to the same as you set it the >first time! So your second call to MyRandCharColors >gives exactly the same colors as the first call.
In this application, that can never happen even if VBA were instantaneous. Most of the time, I run the marco only once. The only times that I run it more than once is if I don't like the colors that result. That takes me at least a few seconds to determine. I'm pretty sure that the clock is ticking at something like millisecond frequency.
>If you haven't noticed this problem it's because >VBA is so slow. But regardless, only _one_ call >to Randomize, at the start of the application, >will make the colors more random. Honest.
In theory (or principle), I agree with you. In this quick and dirty application to make multi-colored titles for greeting cards, it makes absolutely no difference.