www.gusucode.com > datafun 工具箱matlab源码程序 > datafun/movmax.m
%MOVMAX Moving maximum value. % Y = MOVMAX(X,K) for a vector X and positive integer scalar K computes a % centered moving maximum by sliding a window of length K along X. Each % element of Y is the local maximum of the corresponding values of X % inside the window, with Y the same size as X. When K is even, the % window is centered about the current and previous elements of X. The % sliding window is truncated at the endpoints where there are fewer than % K elements from X to fill the window. % % For N-D arrays, MOVMAX operates along the first array dimension whose % size does not equal 1. % % Y = MOVMAX(X,[NB NF]) for a vector X and nonnegative integers NB and NF % computes a moving maximum along the length of X, returning the local % maximum of the previous NB elements, the current element, and the next % NF elements of X. % % Y = MOVMAX(...,DIM) operates along dimension DIM of X. % % MOVMAX(...,MISSING) specifies how NaN (Not-a-Number) values are treated % and can be one of the following: % % 'omitnan' - (default) the maximum of any window containing NaN % values is the maximum of all its non-NaN elements. % If all elements are NaN, the result is NaN. % 'includenan' - the maximum of any window containing NaN values is % also NaN. % % MOVMAX(...,'Endpoints',ENDPT) controls how the maximum is calculated at % the endpoints of X, where there are not enough elements to fill the % window. ENDPT can be either a scalar numeric or logical value or one of % the following: % % 'shrink' - (default) compute the maximum over the number of % elements of X that are inside the window, effectively % reducing the window size to fit X at the endpoints. % 'fill' - compute the maximum over the full window size, % filling missing values from X with -Inf. This is % equivalent to padding X with -Inf at the endpoints. % 'discard' - compute the maximum only when the window is filled % with elements of X, discarding partial endpoint % calculations and their corresponding elements in Y. % This truncates the output; for a vector X and window % length K, Y has length LENGTH(X)-K+1. % % When ENDPT is a scalar numeric or logical value, the missing elements % of X inside the window are replaced with that value and Y remains the % same size as X. % % Example: Compute a 5-point centered moving maximum. % t = 1:10; % x = [4 3 1 -2 -4 -1 0 2 -2 3]; % yc = movmax(x,5); % plot(t,x,t,yc); % % Example: Compute a 5-point trailing moving maximum. % t = 1:10; % x = [4 3 1 -2 -4 -1 0 2 -2 3]; % yt = movmax(x,[4 0]); % plot(t,x,t,yt); % % Example: Compute a 5-point centered moving maximum, padding the ends of % the input with -Inf. % t = 1:10; % x = [4 3 1 -2 -4 -1 0 2 -2 3]; % yp = movmax(x,5,'Endpoints','fill'); % plot(t,x,t,yp); % % Example: Compute a 5-point trailing moving maximum, ignoring the first % 4 window shifts that do not contain 5 input elements. % x = [4 3 1 -2 -4 -1 0 2 -2 3]; % yd = movmax(x,[4 0],'Endpoints','discard'); % % See also MAX, CUMMAX, MOVMIN, MOVSUM % % Copyright 2015 The MathWorks, Inc. % Built-in function.