Fzero function error in MATLAB. Need inputs regarding the ways to combat the error

I can't seem to rectify this error at all.Can anyone let me know how to deal with this error? I always clear all and clc at the beginning of the code so I don't think there's a variable remaining in the workspace

Error using fzero>localFirstFcnEvalError

FZERO cannot continue because user-supplied function_handle ==>

@(c_H) closedsys(c_H,Q_rest_Na_Cl(b),v_W,k_1,k_2,ksp_CACO3,k_H,k_W,N_totCa,N_totC,v_G,T)

failed with the error below.

Array indices must be positive integers or logical values.

Error in fzero (line 295)

localFirstFcnEvalError(FunFcn,FunFcnIn,ME);

Error in line 37

c_H_zero = abs(fzero(closesys_func, c_H))

Given below is the line 295 that is in the MATLAB logs

% Put first feval in try catch

try

fx = FunFcn(x,varargin{:});

catch ME

localFirstFcnEvalError(FunFcn,FunFcnIn,ME);

end

[Matt J]

No, there's nothing we can tell you without being able to run your code.

Answer 1

[Steven Lord]

If Q_rest_Na_Cl is a variable, is b a logical array or does it contain only integer values? If not, you cannot use b to index into Q_rest_Na_Cl.

If Q_rest_Na_Cl is a function, please show us the body of the Q_rest_Na_Cl and closedsys functions. Somewhere in there you're indexing into a variable with an invalid index (a non-integer value, a numeric 0 or a negative integer value, etc.)

You could try calling:

f = @(c_H) closedsys(c_H,Q_rest_Na_Cl(b),v_W,k_1,k_2,ksp_CACO3,k_H,k_W,N_totCa,N_totC,v_G,T)

with the c_H you use as your initial guess and step through the closedsys function in the Debugger.