M = movmax( returns
an array of local
k-point maximum values, where
each maximum is calculated over a sliding window of length
neighboring elements of
odd, the window is centered about the element in the current position.
k is even, the window is centered about the
current and previous elements. The window size is automatically truncated
at the endpoints when there are not enough elements to fill the window.
When the window is truncated, the maximum is taken over only the elements
that fill the window.
M is the same size as
Ais a vector, then
movmaxoperates along the length of the vector.
Ais a multidimensional array, then
movmaxoperates along the first array dimension whose size does not equal 1.
M = movmax(___, returns
the array of moving maximums along dimension
any of the previous syntaxes. For example, if
a matrix, then
movmax(A,k,2) operates along the
A, computing the
sliding maximum for each row.
M = movmax(___, specifies
whether to include or omit
NaN values from the
calculation for any of the previous syntaxes.
NaN values in the calculation while
them and computes the maximum over fewer points.
Centered Moving Maximum of Vector
Compute the three-point centered moving maximum of a row vector. When there are fewer than three elements in the window at the endpoints, take the maximum over the elements that are available.
A = [4 8 6 -1 -2 -3 -1 3 4 5]; M = movmax(A,3)
M = 1×10 8 8 8 6 -1 -1 3 4 5 5
Trailing Moving Maximum of Vector
Compute the three-point trailing moving maximum of a row vector. When there are fewer than three elements in the window at the endpoints,
movmax takes the maximum over the number of elements that are available.
A = [4 8 6 -1 -2 -3 -1 3 4 5]; M = movmax(A,[2 0])
M = 1×10 4 8 8 8 6 -1 -1 3 4 5
Moving Maximum of Matrix
Compute the three-point centered moving maximum for each row of a matrix. The window starts on the first row, slides horizontally to the end of the row, then moves to the second row, and so on. The dimension argument is two, which slides the window across the columns of
A = [4 8 6; -1 -2 -3; -1 3 4]
A = 3×3 4 8 6 -1 -2 -3 -1 3 4
M = movmax(A,3,2)
M = 3×3 8 8 8 -1 -1 -2 3 4 4
Moving Maximum of Vector with
Compute the three-point centered moving maximum of a row vector containing two
A = [4 8 NaN -1 -2 -3 NaN 3 4 5]; M = movmax(A,3)
M = 1×10 8 8 8 -1 -1 -2 3 4 5 5
Recalculate the maximum, but include the
NaN values. When taking the maximum over a group of elements containing at least one
M = movmax(A,3,'includenan')
M = 1×10 8 NaN NaN NaN -1 NaN NaN NaN 5 5
Sample Points for Moving Maximum
Compute a 3-hour centered moving maximum of the data in
A according to the time vector
A = [4 8 6 -1 -2 -3]; k = hours(3); t = datetime(2016,1,1,0,0,0) + hours(0:5)
t = 1x6 datetime Columns 1 through 3 01-Jan-2016 00:00:00 01-Jan-2016 01:00:00 01-Jan-2016 02:00:00 Columns 4 through 6 01-Jan-2016 03:00:00 01-Jan-2016 04:00:00 01-Jan-2016 05:00:00
M = movmax(A,k,'SamplePoints',t)
M = 1×6 8 8 8 6 -1 -2
Return Only Full-Window Maximums
Compute the three-point centered moving maximum of a row vector, but discard any calculation that uses fewer than three points from the output. In other words, return only the maximums computed from a full three-element window, discarding endpoint calculations.
A = [4 8 6 -1 -2 -3 -1 3 4 5]; M = movmax(A,3,'Endpoints','discard')
M = 1×8 8 8 6 -1 -1 3 4 5
A — Input array
vector | matrix | multidimensional array
Input array, specified as a vector, matrix, or multidimensional array.
k — Window length
numeric or duration scalar
Window length, specified as a numeric or duration scalar. When
a positive integer scalar, the centered maximum includes the element
in the current position plus surrounding neighbors. For example, a
three-point maximum defined by a window of length three results in
the following calculation for a vector
[kb kf] — Directional window length
numeric or duration row vector containing two elements
Directional window length, specified as a numeric or duration
row vector containing two elements. When
positive integer scalars, the calculation is over
The calculation includes the element in the current position,
before the current position, and
kf elements after
the current position. For example, a four-point maximum defined by
the directional window
[2 1] results in the following
calculation for a vector
dim — Dimension to operate along
positive integer scalar
Dimension to operate along, specified as a positive integer scalar. If no value is specified, then the default is the first array dimension whose size does not equal 1.
dim indicates the dimension that
along, that is, the direction in which the specified window slides.
Consider a two-dimensional input array,
dim = 1, then
movmax(A,k,1)starts with the first column and slides vertically over each row to compute. The maximum is computed over
kelements at a time. Then it moves to the second column and repeats the computation. This process continues until all columns are exhausted.
dim = 2, then
movmax(A,k,2)starts with the first row and slides horizontally across each column. The maximum is computed over
kelements at a time. Then it moves to the second row and repeats the computation. This process continues until all rows are exhausted.
'omitnan' (default) |
NaN condition, specified as one of these
'omitnan'— Ignore all
NaNvalues in the input. If a window includes only
NaNvalues from the input when computing the maximum, resulting in the output
comma-separated pairs of
the argument name and
Value is the corresponding value.
Name must appear inside quotes. You can specify several name and value
pair arguments in any order as
M = movmax(A,k,'Endpoints','fill')
Endpoints — Method to treat leading and trailing windows
'shrink' (default) |
'fill' | numeric or logical scalar
Method to treat leading and trailing windows, specified as the
comma-separated pair consisting of
one of the following:
|Shrink the window size near the endpoints of the input to include only existing elements.|
|Do not output any maximum values when the window does not completely overlap with existing elements.|
|Substitute nonexisting elements with |
|numeric or logical scalar||Substitute nonexisting elements with a specified numeric or logical value.|
SamplePoints — Sample points for computing maximums
Sample points for computing maximums, specified as the comma-separated
pair consisting of
'SamplePoints' and a vector.
The sample points represent the location of the data in
Sample points do not need to be uniformly sampled. By default, the
sample points vector is
[1 2 3 ... ].
Moving windows are defined relative to the sample points, which
must be sorted and contain unique elements. For example, if
a vector of times corresponding to the input data, then
a window that represents the time interval between
When the sample points vector has data type
then the moving window length must have type
If the sample points are nonuniformly spaced and the
pair is specified, then its value must be
Calculate with arrays that have more rows than fit in memory.
This function supports tall arrays with the limitations:
'SamplePoints' name-value pair is not
For more information, see Tall Arrays.
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Run code in the background using MATLAB®
backgroundPool or accelerate code with Parallel Computing Toolbox™
This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.
Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.
Usage notes and limitations:
'SamplePoints'name-value pair is not supported.
For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).