Keep getting a error while using fminsearch

Question

simulate function code:

function [V] = simulate(I , params)
%parameters
alphaa = params(1);
k = params(2);
ka = params(3);
delb = params(4);
x4 = params(5);
x3 = params(6);
k3 = params(7);
alphac = params(8);
k6 = params(9);
x6 = params(10);
x5 = params(11);
V = 0.77 -(((0.026) ./ (alphaa)).*log((0.09191)./(k.*((((1.56) - ((0.103) .*I))./(ka + (1.56) - ((0.103) .*I))) + (((15.55) .*I .*delb .*(x4 - x3))./((k3 .*ka) + ((15.55) .*I .*delb .*(x4 - x3)))))))) - (((0.0261) ./alphac) .*log(((0.121) .*I)./(k6 .*(((1.85) .*10 .^-4 .*(x6 - x5)) ./ (((2.22) .*(x6 - x5)) - ((0.113) .*k6)))))) - ((0.000049) .*I);
end

calculate_objective function code:

function [value] = calculate_objective(parameters)
%CALCULATE_OBJECTIVE Summary of this function goes here
% Detailed explanation goes here
%loads a table containing 10 rows and 2 columns
load data.mat Dmodeldata;
predicted = simulate(Dmodeldata.Icell, parameters);
[num_rows, num_cols] = size(Dmodeldata.Vcell);
value = zeros(1,10);
for i = 1:num_rows
value = value + sum(((Dmodeldata.Vcell(i,:)) - predicted).^2);
end
end

Estimate_parameters script:

clear;
guess = [0.1,0.3,0.7,0.1,2,1,1,0.6,0.1,4,3];
options = optimset('Display', 'iter');
[solution.parameters] = ...
fminsearch(@calculate_objective, guess, options);
save solution.mat solution;

Error:

Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-10.

Error in fminsearch (line 200) fv(:,1) = funfcn(x,varargin{:});

Error in estimate_parameters (line 9) fminsearch(@calculate_objective, guess, options);

Any help is appreciated. Thank you