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Zach · Posted: Sun Mar 19, 2023 11:01 am Post subject: IDL formatting

As I am new to Fortran and want to learn: so I need to know about formatting in the context of file handling. There is a pletora of information on the Net, but it is difficult to find a well organised, step by step account dealing wih the subject.

This is my first question: could you please direct me to a well organised and clear manual / tutorial on the subject? Secondly, please let me know what the role of IDL formatting is, in the context of Fortran code i.e. can it all be used in any Fortran code?

Thank you.
Zach.

wahorger · Joined: 13 Oct 2014 Posts: 1217 Location: Morrison, CO, USA

Hi Zach,

I took a quick look at IDL, and, yes, it is very similar to FTN, and there are some differences that if used with FTN95 will not result in actual output!

My quick read is that the formatting is based on FTN, but includes additional features not supported by actual implementations of the FTN language. That said, many elements are so close as to be functionally identical. And for these elements, if you get them to display properly in FTN95, they will display identically in IDL.

I can say the best way to learn about FTN95 formatted output is to try some stuff and see what you get!

A caveat: There are a lot of the subcodes in IDL that do not exist in FTN. And, there are limitations on what forms of a format code are required and optional that differ from IDL.

The thing about formatting is this: While a language element like an assignment, a conditional, or a loop can be in a tutorial and be clear enough to be extended in your mind to other similar statements, formatting is more of an artistry. Graph paper is an excellent way to lay out what you wish to present, then you can translate the visual from the graph paper to the program by applying sequential format codes to what you see. Most tutorials I've seen about FORTRAN I/O only deal with very simplistic inputs/outputs (one to a few data elements). To do anything real (like a report) takes a lot more work.

But then again, all languages require extra work to deal with formats!

Zach · Posted: Tue Mar 21, 2023 10:58 am Post subject:

Thank you Wahorger, Zach.