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Re: Strange Bug with numeric double constants [message #14700]

Mon, 22 March 1999 00:00

thompson
Messages: 584
Registered: August 1991

Senior Member

Alex Schuster <alex@rosa.mpin-koeln.mpg.de> writes:

> Hi!

> I just experienced some weird IDL behaviour:

> IDL> help, 1.0d+2.0d

> help, 1.0d+2.0d
> ^
> % Syntax error.

> IDL> help, 1d+2d

> help, 1d+2d
> ^
> % Syntax error.

> Strange, isn't it? There's no problem with byte constants:

> IDL> help, 1b+2b
> <Expression> BYTE = 3

> An additional blank helps:

> IDL> help, 1d +2d
> <Expression> DOUBLE = 3.0000000

> I didn't try IDL 5.2, but it happened with 4.0 and 5.1 on Unix and
> Windows. I guess IDL expects an exponential notation like 1d0, and is
> confused by the nonnumeric plus character.

Wouldn't it be more proper to write these numbers as

IDL> help, 1.0d0+2.0d0

As others have pointed out, IDL is getting confused by putting the +2
immediately after the "d"--it thinks it's part of the exponent. I guess that
IDL usually knows what you meant if you leave the exponent off, but not always
as you found out.

Cheers,

William Thompson

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[Message index]

		Re: Strange Bug with numeric double constants By: thompson on Mon, 22 March 1999 00:00
		Re: Strange Bug with numeric double constants By: Martin Schultz on Mon, 22 March 1999 00:00
		Re: Strange Bug with numeric double constants By: R.Bauer on Mon, 22 March 1999 00:00

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