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# Alex Sha

Last seen: Today Active since 2019

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Non-linear Multi-Variable Fitting

2 months ago | 0

Genetic Algorithm not returning best found solution
Taking my experience, GA is not an efficient and ideal global optimization algorithm, in lots of cases, GA like random reserach ...

2 months ago | 0

Solving a system of Non-linear Equations with Complex numbers
There are much more solutions else: x1: 5000+3401.68025708298i x2: 5000-3401.68025708301i x3: -3.62536433474507+0i x1: 5...

2 months ago | 0

How do I fit a regression equation to find coefficients and exponents?
Although the results may seem strange, mathematically speaking, the result below is the best one: Sum Squared Error (SSE): 87...

2 months ago | 0

How to constraint the values of fitted parameters with lsqcurvefit?
hi, the result is good enough Sum Squared Error (SSE): 0.0105245967805521 Root of Mean Square Error (RMSE): 0.01938758511131 ...

9 months ago | 0

curve fitting tool custom equation
if taking only part of data, for example, from No. 105 to No. 300, then the result will looks good Sum Squared Error (SSE): 111...

10 months ago | 0

The fsolve function fails to give me an answer for seven unknowns. What should I do?
Just doing some equivalent deformation (change division into multiplication), for example, form: f(5)=((x(1)^3)*(x(2))/(x(4)*...

10 months ago | 0

How to curve fit an equation that gets values from another equation?
How about the results below: Residual Sum of Squares (RSS): 34.9122402573179 Root of Mean Square Error (RMSE): 0.9585109100402...

12 months ago | 0

Unable to find explicit solution
One solution seems to be: t: -8.33315732250827

1 year ago | 0

Curve fitting with custom function
It is hard to get stable and unique result for Da125's problem, especially for parameters of "lambda" and "n". refer to the resu...

1 year ago | 0

FItting 3d with fourier
If taking the fitting function as: the result will be: Root of Mean Square Error (RMSE): 0.000481289122874164 Sum of Square...

1 year ago | 1

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FItting 3d with fourier
Hi, give your data as text format, not a picture just.

1 year ago | 0

PARAMETER estimation of kinetic and adsorbtion constant of langmuir hinshelwood haugen watson model
if want all parameters to be positive: Root of Mean Square Error (RMSE): 0.0035717712315911 Sum of Squared Residual: 0.0003572...

1 year ago | 0

How to obtain model parameters by fitting experimental data to the monod model. monod model.
Refer to the results below: Root of Mean Square Error (RMSE): 1.50437634361661 Sum of Squared Residual: 81.4733345963976 Corr...

1 year ago | 0

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curve fitting a custom equation
Hi, all, as mentioned by Walter Roberson, the resule I provided above is obtained by using 1stOpt, the biggest advantage, for 1s...

1 year ago | 0

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I want to solve 2 equations with 2 variables but it cant be solved and the command window shows fsolve stopped because the last step was ineffective
Hi, the result below should be one solution x1: -52.5485799573576 x2: 12.1032014174617

1 year ago | 0

How to solve a system of second order nonlinear differential equations with boundary conditions
Hi, the chart will be given automatically in 1stOpt UI, also you can make chart yourself by using the result data given above. 1...

1 year ago | 0

I need to fits the attached data as in image
Hi, the fitting function "y = p1/(1+Exp(p2+p3*x)+p4*x)^p5" is pretty good for all data set, where y=L, x=T 1: T1-L1: Root of ...

1 year ago | 1

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Objective function is returning undefined values at initial point. lsqcurvefit cannot continue.
The best results are as below, hard to be obtained since the initial-start values are impossible to be guessed reasonally. Root...

1 year ago | 0

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Kinetic parameter estimation and initial time setting
Hi, see the results below: Root of Mean Square Error (RMSE): 4.00513564326846 Sum of Squared Residual: 320.822230419589 Corre...

1 year ago | 0

How to include contratins on 1 variables for this nonlinear system of equations?
Hi, refer to the solutions below: 1: x1: 0.415757622422666 x2: 0.321911265108838 x3: 0.0970690621849188 2: x1: 12.98212823...

2 years ago | 0

Fit points and specify the slope at one of the points
Hi, try the function below: y = p1+p2*x^2-p3*exp(p4*x); to ensure the slope being 0 in point of "x=0.985035", should add a con...

2 years ago | 0

solving set of non linear equation
Hi, refer to the results below: phi1: 0.00687835881390378 phi2: 3.07608732711163

2 years ago | 0

Trouble finding solution of unknown variable in difficult integration problem
Hi, there are two solutions as below: 1: h=0.073660616949704 2: h=0.165217787421255

2 years ago | 0

fsolve is not returning the right solutions
Hi, if you think the solutions should be (1,0,1) or (-1,0,1) , then one equation: F(3) = 1 + 2*x2.^2 + x3.^2; should be: F(3)...

2 years ago | 0

Solving lengthy nonlinear complex equations in complex variables
Try to find numerical solutions as below; y1s.realpart: 11.0169967890388 y1s.imagpart: -125.141575853451 y3s.realpart: 7.8197...

2 years ago | 0

Lsqnonlin_Fitting Data
Hi, if possible, please post out your data of each curve, as well as the fitting equation.

2 years ago | 0

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...

2 years 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...

2 years ago | 0

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