matlab中主要是矩阵运算
矩阵赋值
;是用于换行和结束符,在[]中','可以用' '(空格)代替
a = [1 2 3 4]; %行向量
a1 = [1;2;3;4]; %列向量
a2 = [1 2;3 4]; %矩阵
>>>a
a = 1 2 3 4
>>>a1
a1 = 1
2
3
4
>>>a2
a2 = 1 2
3 4
矩阵运算
>>>每个元素+1,(+,-同理)
>>>a = a + 1
a = 2 3 4 5
>>>a1 = a1 + 1
a1 = 2
3
4
5
>>>A = a2 + 1
A = 2 3
4 5
>>>
% ':'用来切片,例如(1:13,x)选择1到13行,(x,:)选择全部列
>> a2(:,1)
ans =
1
3
>> a1'
% 矩阵转置
ans =
1 2 3 4
>> inv(a2)
% 矩阵的逆
ans =
-2.0000 1.0000
1.5000 -0.5000
>> det(a2)
% 矩阵的秩
ans =
-2
>> det(a)
错误使用 det
矩阵必须为方阵。
>> a = [1 2;3 4];
>> b = [1 2;4 5];
>> a*b
% 直接用'*'是矩阵乘法运算
ans =
9 12
19 26
>> a.*b
% 用'.*'是矩阵元素对应相乘
ans =
1 4
12 20
>> a1 .* a
矩阵维度必须一致。
>> a - b
% 矩阵'+''-'是对应相加减
ans =
0 0
-1 -1
>> a + b
ans =
2 4
7 9
控制流程
% 循环
for i = 1:n
D(i) = sum(T(i,:))
end
% 分支
if(判别条件)
语句块
end
绘图
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颜色与形象参数
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绘图说明
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