Alex Sha
Last seen: Today
150 total contributions since 2019Alex Sha's Badges
Contribute at least one answer each month for 12 consecutive months
Awarded to Alex Sha on 03 Apr 2020
Answer 10 questions that were unanswered for more than 30 days
Awarded to Alex Sha on 09 Jan 2020
3 of your answers have been accepted
Awarded to Alex Sha on 18 Sep 2019
Provide your first answer ever to someone else's question
Awarded to Alex Sha on 22 Apr 2019
Answered
How could I do simutanoues parameter fitting for two series experimental data and multiple datasets?
Hi, post your data please, if possible
How could I do simutanoues parameter fitting for two series experimental data and multiple datasets?
Hi, post your data please, if possible
ongeveer 2 maanden ago | 0
Answered
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
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
3 maanden ago | 0
Answered
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...
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...
3 maanden ago | 1
| accepted
Answered
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...
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...
3 maanden ago | 3
Answered
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...
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...
3 maanden ago | 1
Answered
Nonlinear regression with two variables
Hi, Dipon, post your y, T and pH data please, if possible.
Nonlinear regression with two variables
Hi, Dipon, post your y, T and pH data please, if possible.
4 maanden ago | 0
Answered
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...
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...
4 maanden ago | 0
Answered
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...
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...
4 maanden ago | 0
| accepted
Answered
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 ...
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 ...
4 maanden ago | 1
Answered
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...
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...
4 maanden ago | 0
Answered
Problems fitting couple differential equations to experimental data
Hi, if possible, upload your data (t, P and M) please
Problems fitting couple differential equations to experimental data
Hi, if possible, upload your data (t, P and M) please
4 maanden ago | 0
Answered
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...
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...
4 maanden ago | 0
Answered
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...
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...
4 maanden ago | 0
Answered
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...
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...
4 maanden ago | 0
Answered
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...
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...
4 maanden ago | 0
| accepted
Answered
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...
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...
5 maanden ago | 0
Answered
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...
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...
5 maanden ago | 0
Answered
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...
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...
5 maanden ago | 1
Answered
I am solving 20 nonlinear equation using fsolve to find 20 variables' value. But i previously know one of variable's value. That variable is x(17) in eqn F(17). x(17)=1200. Based on this fixed variable i want to find remaining variables' value.
The equation F(17) seems to be meanless: F(17)= (100e6*((0.5*(x(5)*x(6)+x(7)*x(8)))+(0.5*(x(11)*x(15)+x(12)*x(16))))/(-C*x(17))...
I am solving 20 nonlinear equation using fsolve to find 20 variables' value. But i previously know one of variable's value. That variable is x(17) in eqn F(17). x(17)=1200. Based on this fixed variable i want to find remaining variables' value.
The equation F(17) seems to be meanless: F(17)= (100e6*((0.5*(x(5)*x(6)+x(7)*x(8)))+(0.5*(x(11)*x(15)+x(12)*x(16))))/(-C*x(17))...
5 maanden ago | 0
Answered
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...
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...
5 maanden ago | 0
| accepted
Answered
using least square fit to find the best fit parameters
Hi， Annie， upload your data file please, if possible.
using least square fit to find the best fit parameters
Hi， Annie， upload your data file please, if possible.
5 maanden ago | 0
Answered
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
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
5 maanden ago | 0
Answered
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...
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...
5 maanden ago | 0
Answered
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...
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...
5 maanden ago | 0
Answered
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...
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...
5 maanden ago | 0
Answered
continuity of a fit function in different regions
Hi, the function below meets your requirements， with the derivative to be zero at x=1 y = p1+p2*(((x-p3)*(x+p4))^2)^p5; Root o...
continuity of a fit function in different regions
Hi, the function below meets your requirements， with the derivative to be zero at x=1 y = p1+p2*(((x-p3)*(x+p4))^2)^p5; Root o...
5 maanden ago | 0
Answered
lsqcurvefit not adjusting some parameters as expected
The best solution seems to be: Root of Mean Square Error (RMSE): 8.58712889537096E-5 Sum of Squared Residual: 1.50943288116718...
lsqcurvefit not adjusting some parameters as expected
The best solution seems to be: Root of Mean Square Error (RMSE): 8.58712889537096E-5 Sum of Squared Residual: 1.50943288116718...
6 maanden ago | 0
Answered
Fit multiple data with one mathmatical model/function
Hello, AHMED, your fit function is overdeterminted which will lead to multi-solutions, the parameter of "a1" is redundant: C=a1...
Fit multiple data with one mathmatical model/function
Hello, AHMED, your fit function is overdeterminted which will lead to multi-solutions, the parameter of "a1" is redundant: C=a1...
6 maanden ago | 1
Answered
How to fit a custom equation?
If don't care the type of fitting function, try the below function, much simple but with much better result: y = b1+b2*x^1.5+b3...
How to fit a custom equation?
If don't care the type of fitting function, try the below function, much simple but with much better result: y = b1+b2*x^1.5+b3...
6 maanden ago | 0
Answered
Fitting a sigmoid curve using curve fitting tool box
Hi, Hair, the quailty of your data seems to be bad for sigmoid type of function. If take the function like: y = y0+a/(1+exp(-(x...
Fitting a sigmoid curve using curve fitting tool box
Hi, Hair, the quailty of your data seems to be bad for sigmoid type of function. If take the function like: y = y0+a/(1+exp(-(x...
6 maanden ago | 1
| accepted
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