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ks0297
USA
10 Posts |
 Posted - 09/15/2013 : 12:34:08 AM
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Origin Ver. 8.0 pro SR6, and Service Release (Select Help-->About Origin):
Operating System:win7
I typed following eqn to use as user defined and find the 6 unknown parameters,(a,c,h,b,f,g)
y =(((a*c*exp(-(h*x)^0.5)*h^0.5*x^(3/2))+(b*f*exp(-(g*x)^0.25)*g^0.25*x^(5/4)))/((h*exp(-(h*x)^0.5)+(f*exp(-(g*x)^0.25))
Error msg:
:Error, mismatching usage of parentheses Compile Failed!
Please help to fit my function as the user defined.
Thanks
KS
KS |
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SimpleSimonSays
Germany
6 Posts |
Posted - 09/15/2013 : 07:55:31 AM
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| As the error message said you are missing a closing bracket - there is one more opening one than closing brackets. |
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ks0297
USA
10 Posts |
Posted - 09/16/2013 : 3:21:20 PM
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yes the bracet is adjusted,and it compiles, but my function do not converge. any idea?
Thanks
KS |
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easwar
USA
1964 Posts |
Posted - 09/20/2013 : 09:12:31 AM
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Hi KS,
With these many parameters, it is possible your function is over-parameterized, so the iterative procedure cannot find a unique set of values for all parameters. Try specifying bounds on some of the parameters, if you know what the parameter value roughly ought to be.
Easwar
OriginLab
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ks0297
USA
10 Posts |
Posted - 09/20/2013 : 2:19:21 PM
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in the equation I typed, following are the parameters for guess values:
a=1.1; c=1E-4;h=1E4; b=0.215; f= 1E4; g=2E8
quote:
Originally posted by easwar
Hi KS,
With these many parameters, it is possible your function is over-parameterized, so the iterative procedure cannot find a unique set of values for all parameters. Try specifying bounds on some of the parameters, if you know what the parameter value roughly ought to be.
Easwar
OriginLab
KS |
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easwar
USA
1964 Posts |
Posted - 09/20/2013 : 5:28:23 PM
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Hi KS,
Just giving us parameters won't work, without the data.
Please send your data and your FDF (fitting function) to tech support. You can use the link "Send File to Tech support" on the top right of this page, then refer to this post in your e-mail.
Easwar
OriginLab
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NL fit with user defined eqn