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

Question

RuiQi 2017-2-7

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/323717-failure-in-initial-user-supplied-objective-function-evaluation-lsqcurvefit-cannot-continue

评论： shariq khan 2018-11-18

My code below generates the following error. I have been stuck at it and Im not sure why. It works for an exponential version.

x = load('depth-0.txt');
y = load('mean-0.txt');
F = @(p,x) (p(1) + p(2)*(x*x));
x0 = [-1 1];
[p,resnorm] = lsqcurvefit(F, x0, x, y);
estimate_x = 1:0.1:100;
estimate_y = (p(1) + p(2)*(estimate_x*estimate_x));
plot(estimate_x, estimate_y,'-','LineWidth',2);

Error using * Inner matrix dimensions must agree.

Error in @(p,x)(p(1)+p(2)*(x*x))

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

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

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Answer 1

Walter Roberson 2017-2-7

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https://ww2.mathworks.cn/matlabcentral/answers/323717-failure-in-initial-user-supplied-objective-function-evaluation-lsqcurvefit-cannot-continue#answer_253647

在 MATLAB Online 中打开

F = @(p,x) (p(1) + p(2).*(x.*x));

The parameter you are describing as x will be a matrix. The * operator in MATLAB is algebraic matrix multiplication from linear algebra, which requires that the number of columns of the array on the left hand side be equal to the number of rows of the array on the right hand side of the * operator. With x * x the only way that could happen is if x was square.

The .* operator is element-by-element multiplication.