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Alex Sha


Last seen: Today Active since 2019

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  • Knowledgeable Level 4
  • 12 Month Streak
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Answered
problem in curve fitting using summation of sine functions
@nihal if don't mind fitting function other than summation of sine, much better result will be achieved. For phi_dot data: R...

19 days ago | 0

| accepted

Answered
Exp Fit Error: Error using fit>iFit (line 340) NaN computed by model function, fitting cannot continue. Try using or tightening upper and lower bounds on coefficients.
There are two solutions: 1: Sum Squared Error (SSE): 0.0371625579290083 Root of Mean Square Error (RMSE): 0.0609611006536204 ...

1 month ago | 0

Answered
Possibly spurious solutions - Matlab blocked with no answers
There is a approximate solution for original equations: p2: 35001350.3279785 p3: 35113789.3799513 u2: -8.90075607998193 u3: ...

1 month ago | 0

Answered
Interpolation schemes that produce positive second derivatives of the interpolant
How about to replace interpolation with a fitting function, which ensure non-negative second derivatives: 1: For data: x = [...

2 months ago | 0

Answered
How to find the equation of the data available of a graph?
Try the fitting function below: Sum Squared Error (SSE): 1.05153845767184 Root of Mean Square Error (RMSE): 0.17850714760936...

2 months ago | 0

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Answered
can help me to found empirical equation for data L1 vs T1
How about the one below, much simple and works well: Sum Squared Error (SSE): 0.348116593172766 Root of Mean Square Error (R...

3 months ago | 2

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Answered
can help me to found empirical equation for data L1 vs T1
It is not easy to find a function to describe the curve. Refer to the fitting function and result below: Sum Squared Error (S...

3 months ago | 1

Answered
how to fit the coupled differential equations and get the coefficients?
Refer to the results below: Sum Squared Error (SSE): 46715596564.0427 Root of Mean Square Error (RMSE): 35062.1990798768 Corr...

4 months ago | 0

Answered
Derivative not working plot
Unfortunately, the "exp2" fitting result below given by Matlab is not correctly. theFit = General model Exp2: theF...

4 months ago | 0

Answered
curve fitting exponential function with two terms
If taking the fitting function as: y=a*exp(b*x) + c*exp(d*x); and also taking the data like below directly; x = [6500 6350 580...

5 months ago | 0

Answered
Damped Oscillation Equation Fitting
if taking fitting function as: x=a*exp(-b*t)*sin(w*t+phi) for trial-1 Sum Squared Error (SSE): 9.1948847955911E-5 Root of Mea...

5 months ago | 0

Answered
Fitting a model to my data using non linear least square fit method
The best solution: Root of Mean Square Error (RMSE): 0.0143800358786989 Correlation Coef. (R): 0.998885623657614 R-Square: 0....

6 months ago | 0

Answered
Fsolve don't work good with trigonometric
There are some solutions like below No. 1 2 3 4 5 xa1 0.835289443057692 1.97769580537186 0.119396464246135 0.813305799520437 0...

7 months ago | 0

Answered
fsolve result is not desirable even giving a close starting point
For Qingbin's equations, although it is a problem that has passed a long time, it is worth and interesting to have a try, there ...

7 months ago | 0

Answered
using lsqnonlin with multiple functions
@joshua payne refer to the results below Sum Squared Error (SSE): 0.377485784540046 Root of Mean Square Error (RMSE): 0.082102...

8 months ago | 0

Answered
Least squares linear regression with constraints
If using direct nonlinear fitting a1 59.737732722511 a2 2.72067588034148 a3 -0.192039313150924 Whi...

8 months ago | 0

Answered
How do I curve fit the data set
@Prajwal Magadi, one more function: Sum Squared Error (SSE): 75571.6557870726 Root of Mean Square Error (RMSE): 2.7490299341...

8 months ago | 1

Answered
fitting data with a combination of exponential and linear form ( a*exp(-x/b)+c*x+d )
If taking fitting function as "y=a*exp(-x/b)+c*x+d", the result will be: Sum Squared Error (SSE): 0.473516174967249 Root of Me...

9 months ago | 1

Answered
Fitting multiple exponential function .
@Saroj Poudyal, the result you obtained is not the best one, refer to the global optimization solution below: Sum Squared Error...

10 months ago | 1

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Answered
How to fit multiple gaussian in a curve ?
For the summation of 6 Gaussians function: Sum Squared Error (SSE): 2.61218021364296E-9 Root of Mean Square Error (RMSE): 4.49...

12 months ago | 0

Answered
Curve fitting the data series
Refer to the results below, should be the unique global solution: Sum Squared Error (SSE): 0.0378758633912789 Root of Mean Squ...

12 months ago | 1

Answered
Non-linear Multi-Variable Fitting
If possible, post out your data file please

1 year ago | 0

Answered
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 ...

1 year ago | 0

Answered
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...

1 year ago | 0

Answered
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...

1 year ago | 0

Answered
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 ...

2 years ago | 1

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Answered
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...

2 years ago | 0

Answered
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)*...

2 years ago | 0

Answered
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...

2 years ago | 0

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

2 years ago | 0

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