回复： Re: fminsearch error message

[mbira]

When I try to use fminsearch, I get the error message "LabVIEW:  The given name does not correspond to a know function, variable, or symbol." 

For example, I define a function "testfn" by making an m-file called "testfn.m" containing

funtion z=testfn(x,y)

z=x.^2+y.^2;

return

and I store it in the current directory, and I make sure that this directory is part of the path. Furthermore, when I try it out, like so

testfn(1,2)

the function does execute, and I get the proper value back.  But when I type

X=fminsearch('testfn',[1,1])

I get the error message.

On the other hand, if I type

x=fminsearch('sin',[1])

I get back x= -1.5708, so fminsearch itself seems to be working for me, and I feel like I understand the syntax.  I just don't know how to tell it where to look for my function.

Thanks for any help! 

[ttrr]

Hi,

"The function you specify must accept a vector of the same length as xstart and return a scalar."

See detail in help of fminsearch.

[mbira]

OK, so I think you're telling me that I have to change the .^ operators with ^, so that the function would be unable to accept 1-D arrays.  Is that right?

I change the test function to

function z=testfn(x,y)

z=x^2+y^2

return

and now I get a different error. "A problem occurred in a subVI call."

[ttrr · Accepted solution]

Hi,

Your function should not accept more than one inputs. And, the only input should be a vector.

http://forums.ni.com/ni/board/message?board.id=MathScript&thread.id=361

[mbira]

OK.  Thanks!  That means that the mathscript fminsearch is very restricted compared to the matlab version, and I'll probably have to try a different approach.