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gpoon

USA
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Posted - 06/08/2010 :  01:52:57 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Origin Ver. 8 and Service Release SR6 (Select Help-->About Origin):
Operating System: Windows XP

Hello!

I would know how to access the machine epsilon constant in Origin C. I read that it is accessible as the constant DBL_EPSILON, but that requires float.h, which doesn't seem to be available in Origin C. Alternatively, I tried to use the NAG function x02ajc which should compute this constant, but when I try to call it Origin C says:

Error, Function was called, but its body could not be located during linking.

My limited ability to read the nagx02.h file didn't give me any clues. I would appreciate any insight you can give.

Many thanks!
Gregory

Penn

China
644 Posts
Posted - 06/09/2010 :  01:13:53 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi Gregory,

In Origin 8.0, this constant is not available yet. We are very sorry for that. However, it can be accessed in current version, Origin 8.1 SR3. If you are interested, you can download a demo from this page to have a try.

For a workaround, you can define this constant by yourself. I have run the following code in Origin 8.1 SR3 to get the value.

#include <OC_nag8.h>
void testDBL_EPSILON()
{
	double dDBL_EPSILON = X02AJC;
	printf("d=%16.15e\n", dDBL_EPSILON);
}

And the value is 1.110223024625157e-016.

Penn
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