Risposto

Calculate the normal vector between two nodes in the space

n = [0 0 1] points from A to B. So I don't understand what you mean by "normal" to the line connecting two points in 3d. Usual...

Calculate the normal vector between two nodes in the space

n = [0 0 1] points from A to B. So I don't understand what you mean by "normal" to the line connecting two points in 3d. Usual...

circa un mese fa | 0

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Risposto

Parse error at observed data

% Observed data (replace with actual data) % Format: [time, infected, isolated, treated, recovered] observed_data = [ 0, ...

Parse error at observed data

% Observed data (replace with actual data) % Format: [time, infected, isolated, treated, recovered] observed_data = [ 0, ...

circa un mese fa | 0

Risposto

Multivariate regression for constrained dependent variables

Define a Nx12 matrix A as A = [x11,x12,x13,x14,x15,x16,x21,x22,x23,x24,x25,x26] and a Nx1 vector b as b = ones(N,1) and sol...

Multivariate regression for constrained dependent variables

Define a Nx12 matrix A as A = [x11,x12,x13,x14,x15,x16,x21,x22,x23,x24,x25,x26] and a Nx1 vector b as b = ones(N,1) and sol...

circa un mese fa | 0

Risposto

Newton's method gives NaN. Can someone improve my code?

Your undamped Newton's method throws you from x = 0.5 to x = 46 appr. in the next step. Here, your function cannot be evaluated ...

Newton's method gives NaN. Can someone improve my code?

Your undamped Newton's method throws you from x = 0.5 to x = 46 appr. in the next step. Here, your function cannot be evaluated ...

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Risposto

3D integration over a region bounded by some planes.

f = @(x,y,z)x.^2+y+2*z; N = [100,1000,10000,100000,1000000,10000000,100000000]; Fi = zeros(numel(N),1); Fo = Fi; for i = 1:n...

3D integration over a region bounded by some planes.

f = @(x,y,z)x.^2+y+2*z; N = [100,1000,10000,100000,1000000,10000000,100000000]; Fi = zeros(numel(N),1); Fo = Fi; for i = 1:n...

circa un mese fa | 1

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Risposto

Fitting multiple datasets with unique parameters using lsqcurvefit to a normalized function and constraints between datasets.

If your model functions share common parameters, you must run "lsqcurvefit" on all yi with all parameters present (in your case ...

Fitting multiple datasets with unique parameters using lsqcurvefit to a normalized function and constraints between datasets.

If your model functions share common parameters, you must run "lsqcurvefit" on all yi with all parameters present (in your case ...

circa un mese fa | 0

Risposto

Error in Model Fitting

% Define the time vector and observed data time = [0, 1, 2, 3, 4, 5]; % Example time points observed_I = [10, 15, 20, 25, 30, ...

Error in Model Fitting

% Define the time vector and observed data time = [0, 1, 2, 3, 4, 5]; % Example time points observed_I = [10, 15, 20, 25, 30, ...

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Risposto

Complex Number Ignition Error: Ray transfer matrix analysis

imag(1./q)*lambda/pi is negative, thus sqrt(imag(1./q)*lambda/pi) is complex. MATLAB does not know how you want it to plot ...

Complex Number Ignition Error: Ray transfer matrix analysis

imag(1./q)*lambda/pi is negative, thus sqrt(imag(1./q)*lambda/pi) is complex. MATLAB does not know how you want it to plot ...

circa un mese fa | 0

Risposto

Solving with ode45 with a solution dependant variable in the ode

fun = @(t,y) sum(y)*y; zspan = [0 3e-2]; y0 = [1 2 3 4 5]; [T,Y] = ode45(fun,zspan,y0); plot(T,Y)

Solving with ode45 with a solution dependant variable in the ode

fun = @(t,y) sum(y)*y; zspan = [0 3e-2]; y0 = [1 2 3 4 5]; [T,Y] = ode45(fun,zspan,y0); plot(T,Y)

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Risposto

I'm getting a matrix as output when I'm expecting a vector

Maybe you mean I = ones(n+1,1); instead of I = ones(n+1);

I'm getting a matrix as output when I'm expecting a vector

Maybe you mean I = ones(n+1,1); instead of I = ones(n+1);

circa un mese fa | 2

Risposto

multiplying a function handle by a constant

This is Heun's method, but your solution explodes. I get the same results with a MATLAB ODE integrator like ODE45. You will hav...

multiplying a function handle by a constant

This is Heun's method, but your solution explodes. I get the same results with a MATLAB ODE integrator like ODE45. You will hav...

circa un mese fa | 0

Risposto

Problems by calculating zero points of a cubic function

x=0.1:0.1:0.5; p = arrayfun(@(i)roots([-2 1 x(i) -8]),1:numel(x),'UniformOutput',0); p = cell2mat(p)

Problems by calculating zero points of a cubic function

x=0.1:0.1:0.5; p = arrayfun(@(i)roots([-2 1 x(i) -8]),1:numel(x),'UniformOutput',0); p = cell2mat(p)

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Risposto

I'm getting following error: Array indices must be positive integers or logical values.

Indexing in MATLAB starts with 1, not with 0.

I'm getting following error: Array indices must be positive integers or logical values.

Indexing in MATLAB starts with 1, not with 0.

circa un mese fa | 1

Risposto

Error imposing space-derivative-dependent boundary condition with solvepde using variable state.uy - Error: Unrecognized field name "uy".

According to the documentation (User's guide, page 2-128), g can be a function of x,y,t and u. The boundary condition of a seco...

Error imposing space-derivative-dependent boundary condition with solvepde using variable state.uy - Error: Unrecognized field name "uy".

According to the documentation (User's guide, page 2-128), g can be a function of x,y,t and u. The boundary condition of a seco...

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Risposto

How to build an empiric cdf/pdf of a compound poisson continuos distribution

clear all; close all; clc rng(200724) %mean and standard deviation of a given sample (sample of Yi) mu_c = 4432.62; var_c= 53...

How to build an empiric cdf/pdf of a compound poisson continuos distribution

clear all; close all; clc rng(200724) %mean and standard deviation of a given sample (sample of Yi) mu_c = 4432.62; var_c= 53...

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Risposto

Invalid expression during a function handle

Must read Kernel = @(x) ... instead of Kernel = @x ...

Invalid expression during a function handle

Must read Kernel = @(x) ... instead of Kernel = @x ...

circa 2 mesi fa | 2

Risposto

Help understanding how function handle is used

Somewhere in your code you defined a fitness function which assumes that inputs j and k are integers function fitness = Ft(x,j,...

Help understanding how function handle is used

Somewhere in your code you defined a fitness function which assumes that inputs j and k are integers function fitness = Ft(x,j,...

circa 2 mesi fa | 0

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Risposto

Error in for loop: Index exceeds matrix dimensions.

matrix_f=[1 2 3; 1 2 3; 4 5 6; 7 8 9; 7 8 9; 10 11 12]; unique(matrix_f,'stable','rows') Note that this code will remove all d...

Error in for loop: Index exceeds matrix dimensions.

matrix_f=[1 2 3; 1 2 3; 4 5 6; 7 8 9; 7 8 9; 10 11 12]; unique(matrix_f,'stable','rows') Note that this code will remove all d...

circa 2 mesi fa | 1

Risposto

Why does this technique not work?

I already gave you the code how to order a vector according to the ordering of "u". Why don't you use it ? Your method is wrong...

Why does this technique not work?

I already gave you the code how to order a vector according to the ordering of "u". Why don't you use it ? Your method is wrong...

circa 2 mesi fa | 1

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Risposto

Setting unknown constants in equation for known data

how can i do that ? By solving the system yi - f(xi,a,b,c) = 0 for a,b and c. Here, (xi,yi) are your data points. If f is l...

Setting unknown constants in equation for known data

how can i do that ? By solving the system yi - f(xi,a,b,c) = 0 for a,b and c. Here, (xi,yi) are your data points. If f is l...

circa 2 mesi fa | 1

Risposto

lsqcurvefit issues due to variables being several orders of magnitude different

load('V1.mat') load('Vp.mat') load('data.mat') V = [V1, Vp]; %voltages a = 1.1792; b = 0.5; e = 1.60217662e-19; Area ...

lsqcurvefit issues due to variables being several orders of magnitude different

load('V1.mat') load('Vp.mat') load('data.mat') V = [V1, Vp]; %voltages a = 1.1792; b = 0.5; e = 1.60217662e-19; Area ...

circa 2 mesi fa | 0

Risposto

Please help me understand output from discretize

X=[.01:.01:1] ; % - example data uniformly going form .01 to 1 in steps of .01 binEdges=[0:0.01:1]; %- the bind edges X(6)>b...

Please help me understand output from discretize

X=[.01:.01:1] ; % - example data uniformly going form .01 to 1 in steps of .01 binEdges=[0:0.01:1]; %- the bind edges X(6)>b...

circa 2 mesi fa | 0

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Risposto

How can I solve the error "Unable to solve the collocation equations -- a singular Jacobian encountered" in bvp4c?

Your ODE system is linear - thus you can determine its general solution having 7 free parameters. But incorporating of your boun...

How can I solve the error "Unable to solve the collocation equations -- a singular Jacobian encountered" in bvp4c?

Your ODE system is linear - thus you can determine its general solution having 7 free parameters. But incorporating of your boun...

circa 2 mesi fa | 0

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Risposto

How to Graph integrals?

According to proposition 4, the red curve should be the inverse bidding function X and the blue curve should be the inverse bidd...

How to Graph integrals?

According to proposition 4, the red curve should be the inverse bidding function X and the blue curve should be the inverse bidd...

circa 2 mesi fa | 0

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Risposto

how to plot function with 2 variables? using fsolve or bisection ?

Use "fimplicit": https://uk.mathworks.com/help/matlab/ref/fimplicit.html

how to plot function with 2 variables? using fsolve or bisection ?

Use "fimplicit": https://uk.mathworks.com/help/matlab/ref/fimplicit.html

circa 2 mesi fa | 0

Risposto

how to get a good estimate of the positive parameters that will give a good fit of the curves to real data?

You should avoid defining the same data, parameters and variable definitions multiple times in your code (specific_data, gamma, ...

how to get a good estimate of the positive parameters that will give a good fit of the curves to real data?

You should avoid defining the same data, parameters and variable definitions multiple times in your code (specific_data, gamma, ...

circa 2 mesi fa | 1

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Risposto

How can I find a unique solution within tolerance using solve?

As long as rank(A) equals 3 in the below code, your system of linear equations has a unique solution. syms Rx Risop Rison V1=2...

How can I find a unique solution within tolerance using solve?

As long as rank(A) equals 3 in the below code, your system of linear equations has a unique solution. syms Rx Risop Rison V1=2...

circa 2 mesi fa | 1

Risposto

function must return a column vector

Allocate dy as a column vector before assigning values to it: %Ordinary differential equation dy = zeros(4,1); dy(1)=alpha*(1...

function must return a column vector

Allocate dy as a column vector before assigning values to it: %Ordinary differential equation dy = zeros(4,1); dy(1)=alpha*(1...

circa 2 mesi fa | 0

Risposto

I'm having trouble solving a system of nonlinear equations with the fmincon function.

Use % Options for fmincon options = optimoptions('fmincon', 'Algorithm', 'interior-point', 'Display', 'off','ConstraintToleran...

I'm having trouble solving a system of nonlinear equations with the fmincon function.

Use % Options for fmincon options = optimoptions('fmincon', 'Algorithm', 'interior-point', 'Display', 'off','ConstraintToleran...

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Risposto

Simulation - number of samples

Is there a preset (optimum) value and how is this determined? As big as necessary and as small as possible. You will have to te...

Simulation - number of samples

Is there a preset (optimum) value and how is this determined? As big as necessary and as small as possible. You will have to te...

circa 2 mesi fa | 1

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