MATLAB中l=zeros(size(label))是什么意思
时间: 2024-02-01 12:03:52 浏览: 31
在MATLAB中,`zeros(size(label))`的意思是创建一个与`label`具有相同大小的全矩阵。`size(label)`用于获取`label`矩阵的大小,然后`zeros`函数使用这个大小作为参数来创建一个全零矩阵。这样得到的矩阵 `l` 中的所有元素都是0,并且与 `label` 的维度相匹配。
相关问题
请将下面的matlab代码转换为python代码:function OneError=One_error(Outputs,test_target) [num_class,num_instance]=size(Outputs); temp_Outputs=[]; temp_test_target=[]; for i=1:num_instance temp=test_target(:,i); if((sum(temp)~=num_class)&(sum(temp)~=-num_class)) temp_Outputs=[temp_Outputs,Outputs(:,i)]; temp_test_target=[temp_test_target,temp]; end end Outputs=temp_Outputs; test_target=temp_test_target; [num_class,num_instance]=size(Outputs); Label=cell(num_instance,1); not_Label=cell(num_instance,1); Label_size=zeros(1,num_instance); for i=1:num_instance temp=test_target(:,i); Label_size(1,i)=sum(temp==ones(num_class,1)); for j=1:num_class if(temp(j)==1) Label{i,1}=[Label{i,1},j]; else not_Label{i,1}=[not_Label{i,1},j]; end end end oneerr=0; for i=1:num_instance indicator=0; temp=Outputs(:,i); [maximum,index]=max(temp); for j=1:num_class if(temp(j)==maximum) if(ismember(j,Label{i,1})) indicator=1; break; end end end if(indicator==0) oneerr=oneerr+1; end end OneError=oneerr/num_instance;
以下是将matlab代码转换为python代码的结果:
```python
import numpy as np
def One_error(Outputs, test_target):
num_class, num_instance = Outputs.shape
temp_Outputs = np.empty((num_class, 0))
temp_test_target = np.empty((num_class, 0))
for i in range(num_instance):
temp = test_target[:, i]
if (np.sum(temp) != num_class) and (np.sum(temp) != -num_class):
temp_Outputs = np.concatenate((temp_Outputs, Outputs[:, i].reshape(num_class, 1)), axis=1)
temp_test_target = np.concatenate((temp_test_target, temp.reshape(num_class, 1)), axis=1)
Outputs = temp_Outputs
test_target = temp_test_target
num_class, num_instance = Outputs.shape
Label = [None] * num_instance
not_Label = [None] * num_instance
Label_size = np.zeros((1, num_instance))
for i in range(num_instance):
temp = test_target[:, i]
Label_size[0, i] = np.sum(temp == np.ones((num_class, 1)))
for j in range(num_class):
if temp[j] == 1:
if Label[i] is None:
Label[i] = [j + 1]
else:
Label[i].append(j + 1)
else:
if not_Label[i] is None:
not_Label[i] = [j + 1]
else:
not_Label[i].append(j + 1)
oneerr = 0
for i in range(num_instance):
indicator = 0
temp = Outputs[:, i]
maximum = np.max(temp)
index = np.argmax(temp)
for j in range(num_class):
if temp[j] == maximum:
if (j + 1) in Label[i]:
indicator = 1
break
if indicator == 0:
oneerr += 1
OneError = oneerr / num_instance
return OneError
```
需要注意的是,matlab中的数组索引从1开始,而python中的数组索引从0开始,因此在转换过程中需要将所有的索引减1。
matlab中画坐标系
在Matlab中,可以使用axis命令来绘制坐标系。通过调用axis on函数,可以在绘图时默认显示坐标系。另外,在将坐标轴移动到原点时,可以使用plot函数和text函数来实现。具体的代码如下所示:
uoo=1;
x = -5:0.01:5;
y = uoo*tanh( uoo*x/2^(1/2) );
plot(x,y)
hold on
axis off
box off
% x轴
plot([-5,5],[0,0],'k');
x = get(gca,'XTick');
Lx = get(gca,'XTickLabel');
y = zeros( size(x) ) - 0.1;
text(x, y, Lx);
% y轴
plot([0,0],[-5,5],'k');
y = get(gca,'YTick');
Ly = get(gca,'YTickLabel');
x = zeros( size(y) ) - 0.1;
text(x, y, Ly);