ln not recognised as a command

Question

Niels 2013-7-25

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https://ww2.mathworks.cn/matlabcentral/answers/83155-ln-not-recognised-as-a-command

Hello

I've entered the following formula in a function file:

heightModel = @(params,ages) (params(3)+params(4).*(ages/12)+params(5).*log((1+(ages/12))).*(1-exp(1).^(-exp(1).^(params(1)-params(2).*(ages/12))))+params(6).*exp(1).^(-exp(1).^(params(1)-params(2).*(ages/12)))); modelStrings = {'A','B','C','D','E','U'};

this works perfect but is not the good formula. The only thing that needs to change is the log in a ln

but if i do this i get the following error Undefined function 'ln' for input arguments of type 'double'.

Error in getModel/@(params,ages)(params(3)+params(4).*(ages/12)+params(5).*ln((1+(ages/12))).*(1-exp(1).^(-exp(1).^(params(1)-params(2).*(ages/12))))+params(6).*exp(1).^(-exp(1).^(params(1)-params(2).*(ages/12))))

Error in lsqcurvefit (line 199) initVals.F = feval(funfcn_x_xdata{3},xCurrent,XDATA,varargin{:});

Error in fitFilteredModel (line 13) [parameters,resnorm,residual,exitflag,output] = lsqcurvefit(heightModel,initialValues,filteredData(:,1),filteredData(:,2));

Error in main (line 43) fitFilteredModel(ages(i),models{k},genders{j},data,individualFit);

Caused by: Failure in initial user-supplied objective function evaluation. LSQCURVEFIT cannot continue.

Anyone willing to help me out. I'm a biologist so my coding knowledge is very limited.

Thanks

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Answer 1

Iain 2013-7-25

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You can fix it by putting:

ln = @(x)(log(x));

at the start of your code...

or replace ln with "log"

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Jan 2013-7-25

Faster alternatively: ln = @log

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Answer 2

Evan 2013-7-25

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编辑：Evan 2013-7-25

在 MATLAB Online 中打开

help log

If you read the help file for log, you'll see that it is the natural logarithm function. ln is not a built-in function. log10 is the function for computing the base-10 logarithm.