Rounding Off Number(s) to Specified Significant Figures

Round off number(s) to specified significant figures, using two simple/powerful MATLAB functions.

Description

spa_sf Rounding Off Number(s) to Certain Significant Figures

N = spa_sf(X,SF) is the rounded off number(s) of X with the specified significant figures SF. X could be a scalar or a vector; however, SF must be a scalar.
 
   Example 1)
       X = 3.14159265359;
       SF = 3;
       N = spa_sf(X,SF)

     > N = 3.1400

   Example 2)
       X = 3.14159265359; X=[X,X*2;X*3,X*4];
       SF = 3;
       N = spa_sf(X,SF)

     > N =
           3.1400 6.2800
           9.4200 12.6000

 See also: num2str, str2num
   

* I hope it would be of any help.

• MATLAB release: MATLAB 7.8 (R2009a)
• Other requirements: N/A (I've used this function since MATLAB 6.X.)

[Jos (10584)]

Yes, too simple and its functionality is already abundantly available here of the FEX. However, I should compliment you for the nice help section!

[Yuzo Toya]

The beauty rests in the simplicity of it all, but I am not claiming for its originality -- it's all there in the MATLAB tool package. I decided to share "this code" mainly because of its simplicity, and hope that you will find it useful in any way.

[Yuzo Toya]

Note: This function provides expected results when handing numerical values in double or less precision.

[Robert Orzechowski]

it is nice, but how to round-off complexed values ?

[Geoffrey Lewen]

 

[Neha]

It is not working. I am trying to round off a matrix which contains double values, it shows the error:
Undefined function or method 'spa_sf' for input arguments of type 'double'.

[Yuzo Toya]

Neha, You probably did not place the program / code (spa_sf.m) in the MATLAB's search path. Try running the program after moving the file "spa_sf.m" to the MATLAB's search path or to the current directory. Alternatively, you can set the path to the directory where the file "spa_sf.m" is stored on your computer. (From the Menubar, File >> Set Path...)

[SK]

 

[Yonghao]

How to ceil/floor round to the significant number?