Failure in initial objective function evaluation. LSQCURVEFIT cannot continue.
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Thaer Ismail
on 6 Jan 2020
Commented: Walter Roberson
on 27 Feb 2020
raw = xlsread('File', 2); % read in sheet number 2
Pc = raw(60:141, 1);
Sw = raw(60:141, 9);
plot(Sw,Pc,'ro')
F = @(x,xdata)1-x(1)*exp(-(x(2)/xdata)^(x(3)));
x0 = [3 6 0.6];
[x,resnorm,~,exitflag,output] = lsqcurvefit(F,x0,Sw,Pc)
I keep getting this error.
Error in Skelt_LS_Code (line 16)
[x,resnorm,~,exitflag,output] = lsqcurvefit(F,x0,Sw,Pc)
Caused by:
Failure in initial objective function evaluation. LSQCURVEFIT cannot continue.
Any help is appreciated. Thank you
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Accepted Answer
Walter Roberson
on 6 Jan 2020
F = @(x,xdata)1-x(1)*exp(-(x(2)./xdata).^(x(3)));
6 Comments
Thi Na Le
on 27 Feb 2020
ydata in previous reply was wrong. this is modification:
a0=4;
xdata=...
[5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180];
ydata=...
[0.04178 0.081 0.09475 0.1157 0.1326 0.1468 0.1587 0.169 0.178 0.186 0.193 0.199 0.205 0.211 0.215 0.22 0.224 0.229 0.233 0.238 0.242 0.245 0.248 0.251 0.254 0.257 0.258 0.261 0.264 0.266 0.269 0.272 0.274 0.277 0.273 0.275];
fun=@(x,xdata)a0*(1+((4.5*x(1)*x(2)*xdata)/(5.5+x(2)*xdata)));
x0=[0.01 0.0001];
>> plot(xdata,ydata,'o')
>> x = lsqcurvefit(fun,x0,xdata,ydata)
Error using lsqcurvefit (line 262)
Function value and YDATA sizes are not equal.
More Answers (1)
Alex Sha
on 7 Jan 2020
Hi,Thaer Ismail, which is your exact fit function: "ydata=1-x1*exp(-(x2/xdata)^x3)" or "ydata=1-x1*exp((-x2/xdata)^x3)" ?
if the former, take initial start values as:
x0 = [-23124 0.3 -2.2];
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