What does 0D0 mean?

[gberz3]

Hi All,

My apologies for what is likely a rookie Fortran question, but, what does 0D0 signify at the URL below?:

http://www.adass.org/adass/proceedings/adass98/mighellkj/

I would think that it's just setting the value to 0, but I can't be sure. Not to mention, it wouldn't seem like 0 is a proper fit for at least one of the variables. And it seems that none of the Fortran documentation I've acquired directly addresses 0D0.

Thanks in advance.

 

[xwb]

Double precision 0.

First 0 is the value
D is the same as E meaning x10 to the power of
Second 0 is the exponent

 

[gberz3]

Thank you. Generally, where would I find that out? I'd like a consistent resource to bookmark. I've scoured Language References,Google, and Wikipedia (including cross-references and external links) and found no direct reference to items like that.

One question related to the code itself (if you took a look) why would one set a value to "0D0" only to add it to another value in the loop? If the value set to "0D0" never changes then it seems rather pointless. I could understand the need to *enforce* double precision, but why repeatedly add it through each iteration? Of course, this points to the fact that I'm likely missing something.

Regards

 

[gberz3]

Actually, I see that the value set to "0D0" is changed later so nevermind on that part of my question.

Regards.

 

[xwb]

You'll find the description where they are describing constants. eg 123 for integers, .true. for logicals, 'xyz' for characters, 1.23E4 for reals and 1.23D5 for DP. 0D0 is just a variation on 1.23D5.

I can't really recommend a book or a website. Since I use several languages, I just look for differences in syntax and notation and that's it for me.