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From: Yu Li on 21 Jun 2010 12:53
I am trying to solve a function as below:
function F = B1B2(M,x,k11,L20,k21,k22,J20,H21,MT,NT)

global k11 L20 k21 k22 MT NT J20 H21;

F = 2*L20.*M.^2.*(1+k21.*x+k22.*k21.*x.^2) + M.*(1+k11.*x+...
J20.*NT./(1 + J20.*M + H21.*x.*J20.*M)+...
H21.*J20.*(NT./(1 + J20.*M + H21.*x.*J20.*M)).*x)-MT;

Then I call it from main function:

[M,fval,exitflag,output] = fzero(@(M) B1B2(M,x), MT)

I checked older posts and make all my *, ^ and / scalar. But I still got the error message Operands to the || and && operators must be convertible to logical scalar values.

Error in ==> fzero at 333
elseif ~isfinite(fx) || ~isreal(fx)

Anyone has any clue what is going on?
From: Torsten Hennig on 21 Jun 2010 22:46
> I am trying to solve a function as below:
> function F = B1B2(M,x,k11,L20,k21,k22,J20,H21,MT,NT)
>
> global k11 L20 k21 k22 MT NT J20 H21;
>
> F = 2*L20.*M.^2.*(1+k21.*x+k22.*k21.*x.^2) +
> M.*(1+k11.*x+...
> J20.*NT./(1 + J20.*M + H21.*x.*J20.*M)+...
> H21.*J20.*(NT./(1 + J20.*M +
> *M + H21.*x.*J20.*M)).*x)-MT;
>
> Then I call it from main function:
>
> [M,fval,exitflag,output] = fzero(@(M) B1B2(M,x), MT)
>
> I checked older posts and make all my *, ^ and /
> scalar. But I still got the error message Operands to
> the || and && operators must be convertible to
> logical scalar values.
>
> Error in ==> fzero at 333
> elseif ~isfinite(fx) || ~isreal(fx)
>
> Anyone has any clue what is going on?

1. k11,L20,k21,k22,J20,H21,MT,NT are global
variables ; they need not appear in the
list of parameters for B1B2.
2. The parameter lists for B1B2 in
function F = B1B2(M,x,k11,L20,k21,k22,J20,H21,MT,NT)
and in the call to fzero
fzero(@(M) B1B2(M,x), MT) do not fit.
3. Did you assign a value to the variables you use,
especially MT ?

Best wishes
Torsten.
From: Steven Lord on 22 Jun 2010 13:50

"Yu Li" <yuliyy(a)gmail.com> wrote in message
news:hvo5e3$rf4$1(a)fred.mathworks.com...
>I am trying to solve a function as below: function F =
>B1B2(M,x,k11,L20,k21,k22,J20,H21,MT,NT)
>
> global k11 L20 k21 k22 MT NT J20 H21;
>
> F = 2*L20.*M.^2.*(1+k21.*x+k22.*k21.*x.^2) + M.*(1+k11.*x+...
> J20.*NT./(1 + J20.*M + H21.*x.*J20.*M)+...
> H21.*J20.*(NT./(1 + J20.*M + H21.*x.*J20.*M)).*x)-MT;
>
> Then I call it from main function:
> [M,fval,exitflag,output] = fzero(@(M) B1B2(M,x), MT)
>
> I checked older posts and make all my *, ^ and / scalar. But I still got
> the error message Operands to the || and && operators must be convertible
> to logical scalar values.
>
> Error in ==> fzero at 333
> elseif ~isfinite(fx) || ~isreal(fx)
>
> Anyone has any clue what is going on?

FZERO requires the function that you pass in as its first input to return a
SCALAR value -- you would receive this error if that function returned a
NONscalar value.

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ
To contact Technical Support use the Contact Us link on
http://www.mathworks.com


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