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I've got a graphical program that's exporting a data file with numbers such as: -1.33227e-015 and -4.02456e-016.

I've long been perplexed by the "e-" notation. Is it used to denote an invalid number? What sort of valid value can I extract from the above numbers? What are they trying to say?

Robin Rodricks
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  • Those big negative numbers indicate that the numbers are very, very small, and probably should have been rounded to zero. – Paul Tomblin Sep 17 '10 at 13:51

4 Answers4

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e means "× 10^". It standard for exponent.

e.g. 1.33227e-015 means 1.33227 × 10-15 and -4.02456e-016 means -4.02456 × 10-16.

See http://en.wikipedia.org/wiki/Scientific_notation#E_notation for detail.

kennytm
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No. It signifies exponential/scientific notation. -4.02456e-016 means -4.02456 divided by 10 to the power 16.

Sinan Ünür
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e or E stands for exponent. Just like x10^ (in written mathematics). The number following tells you how far the decimal place is moving, (+ for left, - for right) so your above number:

-1.33227e-015

Becomes:

-.00000000000000133227

While:

-4.02456e-016

Becomes:

-.000000000000000402456

Rudu
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That is scientific notation being used to represent extremely "large" or "small" numbers.

James Sumners
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