优化:for n = 1;NZ for i=1;NY; for j=1;NX; sequence(:, :, :, 1) = rgb2gray(imread(fileNames{n})); if j>(NX*SIZEX/2-sqrt(XD^2-(NY*SIZEY/2-i*SIZEY)^2))/SIZEX j<(NX*SIZEX/2+sqrt(XD^2-(NY*SIZEY/2-i*SIZEY)^2))/SIZEX a(i,j,n)=sequence(i,j,n); else a(i,j,n)=1000; end end end end
时间: 2023-06-15 07:08:00 浏览: 45
优化后的代码如下:
for n = 1:NZ
sequence = rgb2gray(imread(fileNames{n}));
for i = 1:NY
y = NY * SIZEY / 2 - i * SIZEY;
for j = 1:NX
x = j * SIZEX - NX * SIZEX / 2;
if (x^2 + y^2) <= XD^2
a(i, j, n) = sequence(i, j);
else
a(i, j, n) = 1000;
end
end
end
end
优化的主要思路是尽量减少循环嵌套和重复计算。具体来说:
1. 将读取图像的操作移到最外层循环,避免重复读取。
2. 将计算椭圆上的点的操作移到内层循环,避免重复计算。
3. 将计算椭圆上的点的操作改为直接计算椭圆上每个点的坐标,并使用两个变量 x 和 y 分别表示横坐标和纵坐标,避免重复计算。
4. 将原先的 if 判断条件改为计算椭圆上每个点的坐标是否在椭圆内。
相关问题
java.nio.charset.MalformedInputException: Input length = 1
This exception is thrown by the Java NIO CharsetDecoder when it encounters an input byte sequence that is invalid for the given character set. In other words, the input data contains a byte that cannot be decoded into a valid character.
The "Input length = 1" part of the exception message indicates that the invalid input consists of a single byte. The byte may be an unrecognized character, an incomplete or truncated character sequence, or a byte that is not valid for the specified character set.
To fix this issue, you need to identify the source of the invalid input and either correct it or handle it appropriately. This may involve validating the input data before attempting to decode it, using a different character set, or implementing error handling to gracefully handle invalid input.
for i in range(10,0,-1):
This Python code will iterate from 10 to 1 (inclusive) in descending order, with a step of -1.
Here's an example of how you could use this code:
```
for i in range(10,0,-1):
print(i)
```
This would output:
```
10
9
8
7
6
5
4
3
2
1
```
In this example, the `range()` function creates a sequence of numbers from 10 to 1, with a step of -1. The `for` loop then iterates through each number in the sequence, and the `print()` function displays the number on the screen.