Matlab online cannot save values smaller than 10^-20

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Neil Foxman 2019-11-26

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/493202-matlab-online-cannot-save-values-smaller-than-10-20

关闭： MATLAB Answer Bot 2021-8-20

I am trying to use the Boltzman constant (k = 1.38e-23) in an equation, but I keep finding that I am unable to use a variable of this size when saving it. Through guess and check, it seems like matlab cannot save variables smaller than 10^-21 or so.

I am not trying to do any math on this variable yet, just save it, and it seems like an error is still occuring as you can see in the screenshot below (see variable k has a different value than the one I assigned).

I have looked at the links below but they all seem to suggest that Matlab should be able to handle numbers of this size:

https://www.mathworks.com/help/symbolic/digits.html

https://www.mathworks.com/help/matlab/matlab_prog/floating-point-numbers.html

I am using Matlab online, could this be the issue? Or is there some hidden setting that changes the number of bits used?

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the cyclist 2019-11-26

在 MATLAB Online 中打开

I got

k = 1.38e-23
k =
   1.3800e-23

both online and locally.

此问题已关闭。

Answer 1

Neil Foxman 2019-11-26

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/493202-matlab-online-cannot-save-values-smaller-than-10-20#answer_403514

I tried it out on another computer and I was able to get the correct response. However, this doesn't solve the issue. Do you know what setting could be causing this discrepancy?