rms

Root Mean Square (RMS) of array elements.

📝 Syntax

• y = rms(x)

• y = rms(x, dim)

• y = rms(x, vecdim)

• y = rms(x, 'all')

• y = rms(x, dim, type)

• y = rms(x, 'all', type)

• y = rms(x, dim, type, nanflag)

• y = rms(x, 'all', type, nanflag)

📥 Input argument

• x - Input array, specified as a vector, matrix, or multidimensional array: single, double, logical, integer types

• dim - Dimension to operate along, specified as a positive integer scalar.

• 'all' - Operate on all elements of x, returning the RMS value of all elements.

• type - Data type to use in the computation: 'double', 'native'

• nanflag - Missing value condition, specified as: 'includenan', 'includemissing', 'omitnan', 'omitmissing'

📤 Output argument

• y - Root mean square value(s), returned as a scalar, vector, or array.

📄 Description

rms returns the root mean square (RMS) value of the input array elements.

• If x is a vector, y is a scalar.

• If x is a matrix, y is a row vector containing the RMS value for each column (default).

• If x is a multidimensional array, y contains the RMS values computed along the first array dimension whose size does not equal 1, unless another dimension is specified.

The root mean square value of an array x is: $\mathrm{RMS}(x) = \sqrt{ \frac{1}{N} \sum_{n=1}^{N} |x_n|^2 }$ where the summation is performed along the specified dimension(s), and N is the number of elements along those dimensions.

NaN Handling: By default, NaN values are included. Use 'omitnan' or 'omitmissing' to ignore NaNs.

Type Handling: If type is 'native', the computation and output use the same class as the input (e.g., integer input returns integer output).

💡 Examples

RMS Value of Vector

t = 0:0.001:1-0.001;
x = cos(2*pi*100*t);
y = rms(x)
% y = 0.7071

RMS Values of Matrix Columns

x = [4 -5 1; 2 3 5; -9 1 7];
y = rms(x)
% y = [5.8023 3.4157 5.0000]

RMS Values of Matrix Rows

x = [6 4 23 -3; 9 -10 4 11; 2 8 -5 1];
y = rms(x,2)
% y = [12.1450; 8.9163; 4.8477]

RMS Excluding Missing Values

x = [1.77 -0.005 nan -2.95; nan 0.34 nan 0.19];
y = rms(x,"omitnan")
% y = [1.7700 0.2404 nan 2.0903]

RMS with Integer Input and Native Output

M = uint8([10:30:70;20:30:80;30:30:90]);
R = rms(M, 'native')
% R is of class uint8

🔗 See also

conv, max, min.

🕔 History

Version	📄 Description
1.16.0	initial version