%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Matlab
%
% Stefan Roth
% , by oneroad
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (1)
% "%" .
% Matlab ， "..." ，
A = [1, 2; ...
3, 4];
% Matlab ， ，
A
% ， “ ” ，
% “ ” ,Ctrl+a ，Ctrl+b
% Ctrl+d , Tab
%
% “dbstop if error”， ，
% 。
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (2)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (A) Matlab （ ）， ，
A = [1 2; 3 4]; % 2x2
B = [1,2; 3,4]; % ，
% “ ” ， “，”
N = 5 %
v = [1 0 0] %
v = [1; 2; 3] %
v = v' %
v = 1:.5:3 % ， 1
v = pi*[-4:4]/4 %
v = [] %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (B) : ，
m = zeros(2, 3) % 2x3 0
v = ones(1, 3) % 1x3 1
m = eye(3) % 3x3
v = rand(3, 1) % 3x1
% t:
m = zeros(3) % 3x3 0
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (C)
% ：Matlab 1 ， 0
v = [1 2 3];
v(3) %
m = [1 2 3 4; 5 7 8 8; 9 10 11 12; 13 14 15 16]
m(1, 3) % matrix（ ， ）
m(2, :) % （ 2 ）
m(:, 1) % （ 1 ）
m(1, 1:3) % 1 1-3
m(2:3, 2) % 2-3 2
m(2:end, 3) % end
m = [1 2 3; 4 5 6]
size(m) %
size(m, 1) %
size(m, 2) %
m1 = zeros(size(m)) % m 0
who %
whos %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (3)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (A) :
% . ，
% ，
a = [1 2 3 4]'; %
2 * a %
a / 4 %
b = [5 6 7 8]'; %
a + b %
a - b %
a .^ 2 % ( ".")
a .* b % ( ".")
a ./ b % ( ".")
log([1 2 3 4]) %
round([1.5 2; 2.2 3.1]) %
% floor, ceil, ...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (B)
a = [1 4 6 3] %
sum(a) %
mean(a) %
var(a) %
std(a) %
max(a) %
min(a) %
% ， ，
a = [1 2 3; 4 5 6] %
mean(a) %
max(a) %
max(max(a)) %
mean(a, 2) % ，
[1 2 3] * [4 5 6]' %
[1 2 3]' * [4 5 6] %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (C) :
a = rand(3,2) % 3x2
b = rand(2,4) % 2x4
c = a * b %
a = [1 2; 3 4; 5 6]; % 3x2
b = [5 6 7]; % 1x3
b * a %
a = [1 3 2; 6 5 4; 7 8 9]; % 3x3
inv(a) %
eig(a) %
[V, D] = eig(a) % D ,V
[U, S, V] = svd(a) %
% : det, norm, rank, ...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (D) :
a = [1 2; 3 4; 5 6]; % 3x2
b = a(:) % a 6x1
sum(a(:)) %
a = reshape(b, 2, 3) % b 2x3 ，
a = [1 2]; b = [3 4]; %
c = [a b] % 1x3
a = [1; 2; 3]; %
c = [a; 4] % 4x1
a = [eye(3) rand(3)] %
b = [eye(3); ones(1, 3)]
b = repmat(5, 3, 2) % 3x2 5
b = repmat([1 2; 3 4], 1, 2) % 2x4 ， 2x2
b = diag([1 2 3]) % 3x3
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% (4)
% :
%
% for =
%
% ...
%
% end
%
% , . 1:10 or -1:0.5:1 or [1 4 7]
%
%
% while
%
% end
%
% if
%
% elseif
%
% else
%
% end
%
% (elseif else , "end" )
%
% ， . a < b
% <, >, <=, >=, ==, ~= ( C(++) )
% :
% Matlab . Matlab 6.5 。
% ，
%
% :
for i=1:2:7 % 2 1 7
i % i
end
for i=[5 13 -1] %
if (i > 10)
disp('Larger than 10') %
elseif i < 0
disp('Negative value')
else
disp('Something else')
end
end
% : A 1xn v，
% A v
m = 50; n = 10; A = ones(m, n); v = 2 * rand(1, n);
%
% :
for i=1:m
A(i,:) = A(i,:) - v;
end
%
A = A - repmat(v, m, 1); %
% ，
% : mxn A, B，B A
% 0
% :
B = zeros(m,n);
for i=1:m
for j=1:n
if A(i,j)>0
B(i,j) = A(i,j);
end
end
end
%
B = zeros(m,n);
ind = find(A > 0); % A 0
B(ind) = A(ind); %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%(5)
save myfile % MAT
save myfile a b % a b
clear a b % a b
clear %
load myfile % myfile.mat
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%(6) :
%
% Matlab ".m" ，
% ".m" .
% function [ 1, ..., m] = myfunction( 1, ..., n)
%
%
% : .
a = [1 2 3 4]; % a
b = myfunction(2 * a) %
a % a
[c, d] = ...
myotherfunction(a, b) %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%(7)
x = [0 1 2 3 4]; %
plot(x); % x ，
pause % ，
plot(x, 2*x); % 2*x， x
axis([0 8 0 8]); %
figure; %
x = pi*[-24:24]/24;
plot(x, sin(x));
xlabel('radians'); % x
ylabel('sin value'); % y
title('dummy'); %
figure;
subplot(1, 2, 1); % 2x1 ， 1
plot(x, sin(x));
axis square; %
subplot(1, 2, 2);
plot(x, 2*cos(x)); % 2
axis square;
figure;
plot(x, sin(x));
hold on; %
plot(x, 2*cos(x), '--'); % '--'
legend('sin', 'cos'); %
hold off; %
figure;
m = rand(64,64);
imagesc(m) %
colormap gray; %
axis image; %
axis off; %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
本文は51 CTOから出た.COM技術ブログ