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Round to a Specified Number of Significant Digits

4.0 | 3 ratings Rate this file 7 Downloads (last 30 days) File Size: 4.07 KB File ID: #21225 Version: 1.0

Round to a Specified Number of Significant Digits



25 Aug 2008 (Updated )

Rounds a numeric array to a specified number of Significant Digits.

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File Information

sd_round stands for "Significant Digits Round".

This program rounds a 2-d matrix of numbers to a specified number of significant digits.

This program support five different styles of rounding the last digit: to the nearest integer, up, down, toward zero, and away from zero.

This program supports real and complex numbers.

The program outputs the rounded array, a cell string of the rounded matrix, the number of digits, to the left and right of the decimal place.

This program is useful for presenting scientific data that requires rounding to a specifid number of significant digits for publication.


Round2, Fix2, and Round2 inspired this file.

This file inspired Round With Significant Digits and Rounding Functions Collection And Cheat Sheet.

MATLAB release MATLAB 7.5 (R2007b)
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Comments and Ratings (7)
13 May 2013 Will

Will (view profile)

18 Apr 2012 Edward Zechmann

Roundn is in the Mapping Toolbox which costs approximately $1,000.00 for a single user license. It is much simpler; however, it has fewer features and costs $1,000.00. The syntax for using roundn is reproduced from the Mathworks website to help anyone who reads this comment thread. Please let me know if a program with the simple syntax of Roundn would be of benefit to the Matlab Central Users Community.

roundn - Round to multiple of 10n


roundn(x,n) rounds each element of x to the nearest multiple of 10n. The variable n must be scalar, and integer-valued. For complex x, the imaginary and real parts are rounded independently. For n = 0, roundn gives the same result as round. That is, roundn(x,0) == round(x).

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06 Apr 2012 Humayun Kathuria

Guys! Use "roundn" if you want to use a simple MATLAB built-in function.

19 Oct 2011 mathworks2011

23 Aug 2011 Peter

Peter (view profile)

Is it a bug that:

sd_round(1.5000, 2)

==> 1.5000

I hoped for 1.5 as result.

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02 Sep 2008 Edward Zechmann

Dimitri, this submission fixed the error for rounding numbers less than 1. There is an additional example. The number of digits to the left and right of the decimal point is recalcualted after rounding, because rounding can affect the number of digits to the left and right of the decimal point. Please post a comment or send me an e-mail if you find any more bugs or have any questions. Thanks for your previous comments.

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02 Sep 2008 Dimitri Shvorob

.. So how does your submission improve on the older ones?

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