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Estimation of parameters for curvefit using lsqcurvefit
Hi everyone, On the attached script I am trying to use lsqcurvefit to estimate parameters x(1), x(2), x(3), x(4), x(5) and x(...

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Too many input arguments, which arguments should I remove?
Hi all, on the attached code, I am trying to use a for-loop and ode45 to solve odes and an algebraic equation in 31 iterations. ...

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Index exceeds the number of array elements (1)
Hi everyone, I know this error is self-explanatory. In line 34 of the attached code, I indexed to the end of the independent var...

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Why does my for-loop substitute only one value throughout 31 iterations?
Hi all, on the attached file, I am trying to use the for-loop to substitute values for every iteration. However, it seems like ...

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How can I fit data to a curve that is only defined implicitly
Hello everyone, I am learning how to fit data to a curve that is only defined implicitly. For practice, I am using the function ...

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Why does fprintf return different values from the plot
Hi all, when I run the attached code, the values that are returned by fprintf command are different from those on the plot. What...

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Where in the code, and how should I define y? (A clearer presentation of the question)
Hi all, this serves to present the question in a detailed manner. In the attached code, I am trying to solve 7 ODEs, dydt(1...

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Unable to perform assignment because the left and right sides have a different number of elements.
Hi all, I don't know why does my code give an error message: Unable to perform assignment because the left and right sides ...

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How can I use for-loop to implement variable parameters?
Hi all, on the attached m-file I try to use for-loop to pass variable parameters, some how I get an error message that says: ...

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Does my code make sense? It runs without errors, but I'm not sure if I did the right thing.
Hi all. On the attached code, I am interested in solving for x (using the @xfun function) and solving for y(1)...y(6), using the...

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How can I increase vector size of the output from 7 x 7 double to 30 x 7 double i.e how can I make a for-loop to repeat 30 times?
Hi all, How can I increase the size of the output vector of the attached m-file (EulerMethod.m) from 7 x 7 double to 30 x 7 dou...

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How can I make matrix dimensions to agree?
Hi all, I get an error message: Matrix dimensions must agree. Error in lsqcurvefit/objective (line 279) ...

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How can I increase the output vector of a loop from a 7 x 7 double to a 31 x 7 double?
Hi everyone, I would like to use a for loop (employing Euler method) to solve ODEs and algebraic equations. However, loop only g...

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Error using plot Vectors must be the same length.
Hi everyone, How can I change the size of Cfit in line 140 of the attached to double(30 x 8), in the attached code. When I ru...

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Which input arguments are missing on my code?
Hi everyone, apologies for flooding the forum with question. I am faced with expulsion from the University if I don't solve this...

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lsqcurvefit gives an error message:“Index exceeds array bounds.”
I have a set of 7 ordinary differential equations and 1 algebraic which I use to calculate the concentrations of 8 species with ...

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Too many output arguments error when using lsqcurvefit
I have a set of 7 ordinary differential equations and 1 algebraic which I use to calculate the concentrations of 8 species with ...

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Estimation of parameters and initial conditions using lsqcurvefit gives an error message :"Index Exceeds Array Bounds"
Hi everyone, I tried different approaches to emulate Dave Black's method: https://www.mathworks.com/matlabcentral/answers/329...

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Estimation of parameters and initial conditions using lsqcurvefit
Hi everyone, I am trying to follow the example from the link: https://www.mathworks.com/matlabcentral/answers/329901-solving-...

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Parameter estimation when solving DAE using ODE15i solver
Hi everyone, Is it possible to estimate parameters/curve fitting when solving solving DAE using ODE15i solver? Has anyone don...

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How can I check which parameters is invalid in my code?
Hi everyone, I am trying to run an ODE15i code. I get an error message: " Error using mupadengine/feval (line ...

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A PDE equation giving meaningless results
Hi Everyone, I am trying to solve a simpe PDE equation using pdepe, however I get meaningless results. Please see the code be...

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Did matlab really fail to solve this system of 4 DAEs or did I make a mistake somewhere?
Hi everyone, I'm trying to analytically solve a system of 4 DAEs, however all outputs are blank. Please see the code below: ...

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What is the meaning of "Index in position 1 exceeds array bounds (must not exceed 5)".
Hi everyone, I'm trying to run a code below: syms a(x) b(x) c(x) d(x) e(x) A B C D E FF G H eqn1 = A * diff(a(x),x,2) +...

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Is it possible to use lsqcurvefit for parameter estimation while using ODE15i solver?
Hi everyone, I am trying to estimate 14 parameters. The code below is with guessed parameters, and it does not give errors, h...

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Unable to perform assignment because brace indexing is not supported for variables of this type.
Hi everyone, I am trying to run this code: clear all close all clc syms x(t) y(t) z(t) A B C D E FF ...

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Index in position 1 exceeds array bounds (must not exceed 1)
Hi everyone, when I run the code below (or in the attachment), I get the error message: " Index in position 1 exceeds ar...

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Unable to reproduce a working code for threepointbvp
Hi everyone, I am struggling to reproduce a working threepointbvp code. Please see attached or below. What am I doing wrong? ...

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Index exceeds array bounds error message in a three-point bvp
Hi everyone, I'm trying to solve a three-point bvp, following: https://www.mathworks.com/help/releases/R2018a/matlab/ref/bvpi...

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Error message: Invalid index.
Hi everyone, I am trying to solve two second order differential equations with two unknowns. However, matlab gives the warning t...

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