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mahajan

India
1 Posts

Posted - 05/09/2021 : 07:37:05 AM

Origin Ver. and Service Release (Select Help-->About Origin): OriginPro 2019b (64-bit)
9.6.5.169 (Academic)

Operating System:Windows 10

Hi

I want to make a user defined function for fitting some data. The function contains variables which are defined by other equations. See below..
y is the dependent variable and T is the independent variable.
J, a, g are fitting parameters.
I tried to use the function form as origin C but it did not compile (I am not sure how to define the intermediate variables N1, N2 etc.). If I used the function form as Equations then it seemed to work...it could calculate the value of y for a sample value of T. But in this case, I can not simulate the curve (that option seems grayed out).
Kindly let me know how to build the fitting function so that I can simulate the curve for various choice of parameters.

thanks

Avinash Mahajan
------------------
N1=0.63427990 - 2.06777217*a - 0.70972219*a^2 + 4.89720885*a^3 - 2.80783223*a^4
N2=0.18776962 - 2.84847225*a + 5.96899688*a^2 - 3.85145137*a^3 + 0.64055849*a^4
N3=0.033603617 - 0.757981757*a + 4.137970390*a^2 - 6.100241386*a^3 + 2.701116573*a^4
N4=0.0038611069 + 0.5750352896*a - 2.3359243110*a^2 + 2.934083364*a^3 - 1.1756629304*a^4
N5=0.00027331430 - 0.10724895512*a + 0.40345647304*a^2 - 0.48608843641*a^3 + 0.18972153852*a^4
N6=0 + 0.00578123759*a - 0.02313572892*a^2 + 0.02892774508*a^3 - 0.01157325374*a^4
N71=2.59870347e-7
N72= -2.39236193e-7
DeltaNotStar =(1-a)^(3/4)*(1+a)^(1/4) + 0.38658545*a*(1-a) - 0.20727806*a^2*(1-a)^2
ypower=4.69918784

D1=-0.11572010 - 1.31777217*a + 1.29027781*a^2 + 3.39720885*a^3 - 2.80783223*a^4
D2=0.08705969 - 1.44693321*a + 5.09401919*a^2 - 10.51861382*a^3 + 8.97655318*a^4+5.75312680*a^5 - 11.83647774*a^6 + 4.21174835 *a^7
D3= 0.00563137 + 0.65986015*a - 1.38069533*a^2 - 0.09849603*a^3 + 7.54214913*a^4-22.31810507*a^5 + 27.60773633*a^6 - 6.39966673*a^7 - 15.69691721*a^8 + 13.37035665*a^9 - 3.15881126*a^10
D4=0.0010408866 + 0.1008789796*a - 0.9188446197*a^2 + 1.6052570070*a^3 - 0.7511481272*a^4
D5=0.0000683286 + 20.1410232710*a + 0.6939435034*a^2 - 0.9608700949*a^3 + 0.4106951428*a^4
D6=0 + 0.0367159872*a - 0.1540749976*a^2 + 0.1982667100*a^3 - 0.0806430233*a^4
D7=0 - 0.00314381636*a + 0.01140642324*a^2 - 0.01338139741*a^3 + 0.00511879053*a^4
D81=1.25124679e-7
D82=-1.03824523e-7
zpower=3.55692695

DeltaFitStar = 1 - (1/2)*a - 2*a^2 + (3/2)*a^3

DEN = 1 + D1*(J/T) + D2*(J/T)^2 + D3*(J/T)^3 + D4*(J/T)^4 + D5*(J/T)^5 + D6*(J/T)^6 + D7*(J/T)^7 + (D81*a+D82*a^2)*(DeltaNotStar*(J/T))^zpower*(J/T)^8*exp((DeltaNotStar - DeltaFitStar)*(J/T))
NUM = 1 + N1*(J/T) + N2*(J/T)^2 + N3*(J/T)^3 + N4*(J/T)^4 + N5*(J/T)^5 + N6*(J/T)^6 + (N71*a+N72*a^2)*(DeltaNotStar*(J/T))^ypower*(J/T)^7

y=0.375*g^2*exp(-DeltaFitStar*(J/T))*(1/(4*T))*NUM/DEN
------------------

YimingChen

1592 Posts

Posted - 05/10/2021 : 09:09:09 AM

You will need to follow OriginC language syntax:
1. For intermediate variable, you need to specify the variable type.
2. End each line with semicolon.

e.g.

double N1=0.63427990 - 2.06777217*a - 0.70972219*a^2 + 4.89720885*a^3 - 2.80783223*a^4;

James

Edited by - YimingChen on 05/10/2021 09:10:03 AM

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