blocks|key|3362118|text|错误代码表示找不到函数定义。确保从存储divrat.m文件的同一工作区调用函数。并确保divrat函数不是子函数，它应该是文件中的第一个函数声明。您还可以尝试调用同一divrat.m文件中的函数，以查看问题是与工作区选择有关还是与函数有关。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3362119|顺便问一下，你为什么不直接说|3362120|s+=+sqrt(diag(C));|code-block|syntax|javascript|3362121|难道不是一样的吗？|3362122|entityMap^0|J|8|17|6|2B|8|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|Z|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|P|$]]

The error code indicates the function definition cannot be found. Make sure you're calling the function from the same workspace as the <code>divrat.m</code> file is stored. And make sure <code>divrat</code> function is not a subfunction, it should be first function declaration in the file. You can also try to call the function from the same <code>divrat.m</code> file in order to see if the problem is with workspace selection or the function.

By the way, why didn't you simply say 

<pre><code>s = sqrt(diag(C));
</code></pre>

Wouldn't it be the same?

blocks|key|360907|text|另外，将其命名为divrat.m，而不是divrat.M。这在大多数OSes上应该没什么关系，但是谁知道呢...|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|360908|您还可以使用which命令来测试matlab是否可以找到一个函数。|360909|which+divrat|code-block|syntax|javascript|360910|entityMap^0|8|8|K|8|0|6|5|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

Also, name it <code>divrat.m</code>, not <code>divrat.M</code>. This shouldn't matter on most OSes, but who knows...

You can also test whether matlab can find a function by using the <code>which</code> command, i.e. 

<pre><code>which divrat
</code></pre>

blocks|key|3362179|text|该函数本身是有效的matlab代码。问题一定出在别的地方。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3362180|尝试从它所在的目录中调用该函数，或者使用addpath('pathname')将该目录添加到您的搜索路径中。|offset|length|style|CODE|3362181|entityMap^0|0|K|J|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

The function itself is valid matlab-code. The problem must be something else. 
Try calling the function from within the directory it is located or add that directory to your searchpath using <code>addpath('pathname')</code>.

blocks|key|3362197|text|此问题最常见的原因是Matlab在其搜索路径上找不到该文件。基本上，Matlab在以下位置查找文件：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3362198|3362199|当前目录(pwd);|ordered-list-item|offset|length|style|CODE|3362200|Directly中的路径(要查看路径，请在命令行中键入path+)|3362201|位于名为@(whatever+the+class+of+the+first+argument+is)的目录中，该目录位于上述任何目录中。|3362202|3362203|正如其他人所建议的，您可以使用which命令，但在这种情况下，这通常没有帮助-它会告诉您Matlab找不到您已经知道的文件。|3362204|因此，首先要做的是确保文件在路径上是可定位的。|3362205|接下来要做的是确保matlab正在查找的文件(使用哪个)需要的类型与您实际传递的第一个参数的类型相同。I.el，如果w应该是不同的类，那里有一个divrat函数，但w实际上是空的，[]，所以matlab正在寻找Double/divrat，当只有一个@(yourclass)/divrat.时，这只是我的猜测，但这经常让我头疼。|3362206|entityMap^0|0|0|5|3|0|R|4|0|4|1A|0|0|F|5|0|0|1M|1|20|6|2A|1|2I|2|2X|D|3G|K|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|X|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|Y|8|@$F|Z|G|10|H|I]]|9|@]|A|$]]|$1|J|3|K|5|E|7|11|8|@$F|12|G|13|H|I]]|9|@]|A|$]]|$1|L|3|M|5|E|7|14|8|@$F|15|G|16|H|I]]|9|@]|A|$]]|$1|N|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|18|8|@$F|19|G|1A|H|I]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1C|8|@$F|1D|G|1E|H|I]|$F|1F|G|1G|H|I]|$F|1H|G|1I|H|I]|$F|1J|G|1K|H|I]|$F|1L|G|1M|H|I]|$F|1N|G|1O|H|I]]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1P|8|@]|9|@]|A|$]]]|V|$]]

The most common cause of this problem is that Matlab cannot find the file on it's search path. Basically, Matlab looks for files in: 

<ol>
<li>The current directory (<code>pwd</code>);</li>
<li>Directly in a directory on the path (to see the path, type <code>path</code> at the command line) </li>
<li>In a directory named <code>@(whatever the class of the first argument is)</code> that is in any directory above. 
As someone else suggested, you can use the command <code>which</code>, but that is often unhelpful in this case - it tells you Matlab can't find the file, which you knew already. 
 
So the first thing to do is make sure the file is locatable on the path. 

Next thing to do is make sure that the file that matlab is finding (use which) requires the same type as the first argument you are actually passing. I.el, If <code>w</code> is supposed to be different class, and there is a <code>divrat</code> function there, but <code>w</code> is actually empty, <code>[]</code>, so matlab is looking for <code>Double/divrat</code>, when there is only a <code>@(yourclass)/divrat.</code> This is just speculation on my part, but this often bites me.</li>
</ol>

blocks|key|3149416|text|当函数不在MATLAB路径或pwd中时，会出现此错误。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3149417|首先，确保您能够使用以下命令找到该函数：|3149418|>>+which+divrat
c:\work\divrat\divrat.m|code-block|syntax|javascript|3149419|如果它返回：|3149420|>>+which+divrat
'divrat'+not+found.|3149421|它不在MATLAB路径上，也不在PWD中。|3149422|其次，使用PATH命令确保包含divrat的目录在MATLAB路径上。可能是您认为路径上的某个目录实际上并不在路径上。|offset|length|style|CODE|3149423|最后，确保您使用的不是“私有”目录。如果divrat位于名为private的目录中，则可以通过父目录中的函数访问它，但不能从MATLAB命令行访问：|3149424|>>+foo

ans+=

+++++1

>>+divrat(1,1)
???+Undefined+function+or+method+'divrat'+for+input+arguments+of+type+'double'.

>>+which+-all+divrat
c:\work\divrat\private\divrat.m++%25+Private+to+divrat|3149425|entityMap^0|0|0|0|0|0|0|5|4|F|6|0|K|6|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@$Q|17|R|18|S|T]|$Q|19|R|1A|S|T]]|9|@]|A|$]]|$1|U|3|V|5|6|7|1B|8|@$Q|1C|R|1D|S|T]]|9|@]|A|$]]|$1|W|3|X|5|F|7|1E|8|@]|9|@]|A|$G|H]]|$1|Y|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|Z|$]]

You get this error when the function isn't on the MATLAB path or in pwd.

First, make sure that you are able to find the function using:

<pre><code>&gt;&gt; which divrat
c:\work\divrat\divrat.m
</code></pre>

If it returns:

<pre><code>&gt;&gt; which divrat
'divrat' not found.
</code></pre>

It is not on the MATLAB path or in PWD.

Second, make sure that the directory that contains <code>divrat</code> is on the MATLAB path using the <code>PATH</code> command. It may be that a directory that you thought was on the path isn't actually on the path.

Finally, make sure you aren't using a "private" directory. If <code>divrat</code> is in a directory named private, it will be accessible by functions in the parent directory, but not from the MATLAB command line:

<pre><code>&gt;&gt; foo

ans =

 1

&gt;&gt; divrat(1,1)
??? Undefined function or method 'divrat' for input arguments of type 'double'.

&gt;&gt; which -all divrat
c:\work\divrat\private\divrat.m % Private to divrat
</code></pre>

blocks|key|3362244|text|我非常确定发生这个问题的原因是因为这个函数所属的工具箱(包)的许可证。编写which+divrat并查看结果。如果它返回函数的路径和注释Has+no+license+available，则问题与许可证有关。这意味着，软件包的许可证设置不正确。大多数情况下，如果该函数的包(工具箱)是在以后添加的，即在安装原始matlab之后发生的。请检查并解决许可问题，然后就可以正常工作了。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3362245|entityMap^0|11|C|1W|O|4A|6|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|O|8|@]|D|@]|E|$]]]|G|$]]

I am pretty sure that the reason why this problem happened is because of the license of the toolbox (package) in which this function belongs in. Write <code>which divrat</code> and see what will be the result. If it returns path of the function and the comment <code>Has no license available</code>, then the problem is related to the license. That means, license of the package is not set correctly. Mostly it happens if the package (toolbox) of this function is added later, i.e., after installation of the original <code>matlab</code>. Please check and solve the license issue, then it will work fine.

I'm a new user of Matlab, can you please help: 
I have the following code in an .M file:

<pre><code>function f = divrat(w, C)
S=sqrt(diag(diag(C)));
s=diag(S);
f=sqrt(w'*C*w)/(w'*s);
</code></pre>

I have stored this file (divrat.M) in the normal Matlab path, and therefore I'm assuming that Matlab will read the function when it's starting and that this function therefore should be available to use.

However, when I type

<pre><code>&gt;&gt; divrat(w, C)
</code></pre>

I get the following error

<blockquote>
 ??? Undefined function or method 'divrat' for input arguments of type 'double'. 
</blockquote>

What is the error message telling me to do, I can't see any error in the code or the function call?

MATLAB error: Undefined function or method X for input arguments of type 'double'

我是Matlab的新用户，您能帮助我吗？我在一个.M文件中有以下代码：function f = divrat(w, C)S=sqrt(diag(diag(C)));s=diag(S);f=sqrt(w'*C*w)/(w'*s);我已经将这个文件(divrat.M)存储在正常的Matlab路径中，因此我假设Matlab将...

问MATLAB错误：'double‘类型的输入参数的函数或方法X未定义
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