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Alex Sha

Last seen: 1 day ago
153 total contributions since 2019

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How to Fit a line to scatter data on scatter plot?
Hi, Chetan, if you don't mind the length of the fitting equation, refer to follow: x1=Speed, x2=Dp, y=Eff y = b0+b1*x1+b2*x1^2...

13 days ago | 0

Fitting a Custom Sigmoid
Hi，if the fitting function is： 1：y=a1*exp(-a2*exp(x)) Root of Mean Square Error (RMSE): 0.291990919479646 Sum of Squared Resi...

1 month ago | 0

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Options when drawing using the Curve Fitting tool
Hi, post your data and function in txt format, if possible.

1 month ago | 0

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Using vpasolve to iterate/solve for flowrate in a piping network
refer to the result below: f1: 0.013713131883721 v1: 1.36937309476078 re1: 409175.227518161

4 months ago | 0

Solving set of 5 non-linear simultaneous equations using fsolve
Hi, Anahita, if you don't want complex answers, then there are problems in your eauqtions, here taking second equation as an exa...

5 months ago | 1

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Deconvolution of Guassian curve
Hi, you may try 4 Gauss Function: The results will be: Root of Mean Square Error (RMSE): 451.21462729511 Sum of Squared Res...

5 months ago | 3

curve fitting toolbox for y=y0.exp((x0/x)^v) where data is known, but y0,x0 and v are unknown constants
Hi, Em, if fit as the function: y=y0.exp((x0/x)^v), then the result will be about： Root of Mean Square Error (RMSE): 9.39279339...

5 months ago | 1

Nonlinear regression with two variables
Hi, Dipon, post your y, T and pH data please, if possible.

5 months ago | 0

How can I solve this system of equation
Hi, VinceUgo, the eqn8 and eqn9 can be combined into one equation, so your problem become a system equation solving with eight e...

5 months ago | 0

Fitting data to an equation with complex part
lsqcurvefit is seneitive to initial start-values since it use local optimization algorithm, same as cftool, there is a GA toolbo...

6 months ago | 0

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Failure in initial objective function evaluation. FSOLVE cannot continue
You have three equations with three unknown parametrs, but initial start-values, you provide two only (x0=[1 1];), is this your ...

6 months ago | 1

i need to solve 7 nonlinear equations with 7 unknows
refer the results below: Constant G x2 x1 x4 x3 x5 x6 x7 600 301.524350251906 299.992603098721 301.890052790606 305.9220213239...

6 months ago | 0

Problems fitting couple differential equations to experimental data

6 months ago | 0

How to improve accuracy in fsolve?
There are multi-solutions with high enough accurancy, even given the range limition in [0, pi/2]: 1: a1: 0.996298496311242 a2...

6 months ago | 0

Create a model to solve an energy balance
Hi, I get two solutions: No. 1 2 tg -328.861557610457 -549.471818197512 tm 1.72830356360143 -541.712011528394 hrpg -0.007275...

6 months ago | 0

Fitting a profile to a Guassian Model
Hi, would you please upload your data file (dependent: alpha, independent variables: Temperature T, Pressure P, mass flow rate m...

6 months ago | 0

How to fit complicated function with 3 fitting parameters using Least square regression
Hi, you may try to use "lsqcurvefit" command or curve fitting tool box (cftool), it is also better if you post data as well as k...

6 months ago | 0

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Why is this not working
There are another five more solutions: No. x1 x2 x3 x4 x5 x6 x7 x8 x9 1 300 200 200 0 0.0447213595499958 -0.0447213595499958 3...

7 months ago | 0

Fsolve complex results make no sense
Hi, Frederic Kluser, with your second case of Eq(9), I get the results below, all seem to be prefect: p: 1.79143003389998 p1_h...

7 months ago | 0

Optimization of 9 unknown with 9 nonlinear constraints by fmincom
one inequality constraint is: x(1)-x(2)+x(3)-x(4)+x(5)-x(6)+x(7)-x(8)+x(9)<=0 (1) while one of equality constraint is: J*(x...

7 months ago | 1

How to guess initialization parameters for non-linear curve fitting with nlinfit?
Hi, Aindrila, guessing the initial start value is always a difficult task since the local optimization algorithms are adopted in...

7 months ago | 0

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using least square fit to find the best fit parameters

7 months ago | 0

How to solve 3 non-linear equations with 3 unknowns?
One of numerical solution looks like: x: 4.49127153145489E-101 y: 0.0437692354838294 z: 867273686630772

7 months ago | 0

How can I fit this data?
Hi, toon, how about the model function below: z = (p1+p2*x+p3*x^2+p4*y+p5*y^2)/(1+p6*x+p7*x^2+p8*x^3+p9*y+p10*y^2); where x: s...

7 months ago | 0

How do I find the coefficients of a function for a curve fit?
The below should be the best solution: Root of Mean Square Error (RMSE): 0.0255893453091926 Sum of Squared Residual: 0.0471466...

7 months ago | 0

Matlab curve fitting two equations simultaneously with common arguments
Hi, Liu, your fitting functions are overdeterminted, there are multi-solutions: 1: Root of Mean Square Error (RMSE): 0.1634941...

7 months ago | 0