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Error using PDEPE Function (Column Vector Mismatch)

This is the error I get: Unexpected output of PDEFUN. For this problem PDEFUN must return three column vectors of length 2. ...

2 years ago | 1 answer | 0

Question

How would the "a" and "c" coefficients be defined in a coupled non-linear set of 2 PDEs?

I have these two coupled non-linear set of PDEs that I have expressed in the standard MATLAB PDE form: <</matlabcentral/answe...

2 years ago | 1 answer | 0

Question

Plot a variable in x-y plane.

I have two variables: "z" and "v" which have the following relationship with x and y: z = x^2 - y^2 v = 2xy Its basical...

3 years ago | 1 answer | 0

Question

2D plot x-y axis

How can visualize on a 2D plot the variation of a variable say, z of size (100,1), that varies with both x and y, both of size (...

4 years ago | 1 answer | 0

Question

How to solve a set of 4 first-order non-linear coupled ODEs?

I am trying to solve a 4th order differential equation using shooting method by disintegrating the ODE into four coupled first o...

6 years ago | 2 answers | 0

Question

How to solve a set of coupled ODEs (4th Order)?

Could somebody help me solve this set of four coupled ODEs? tpcl = @(xi,y) [y(2); ((1 + (y(2)*y(2)))^(1.5))*(y(3) - (A/(y(1)...

6 years ago | 0 answers | 0

Answered

Solving coupled ODE's by ode45

Star Strider, could you please help me solve this set of four coupled ODEs? tpcl = @(xi,y) [y(2); ((1 + (y(2)*y(2)))^(1.5))*...

Solving coupled ODE's by ode45

Star Strider, could you please help me solve this set of four coupled ODEs? tpcl = @(xi,y) [y(2); ((1 + (y(2)*y(2)))^(1.5))*...

6 years ago | 0

Answered

Help with trapz(): Getting complex values

Per, How do I make that value real then?! And why would a simple integration result in a complex value at all?

Help with trapz(): Getting complex values

Per, How do I make that value real then?! And why would a simple integration result in a complex value at all?

7 years ago | 0

Question

Help with trapz(): Getting complex values

Here is my code: I am getting complex values for "T_integral" and that is messing up my temperature profile TSil. Any help will ...

7 years ago | 2 answers | 0

Question

How to integrate a matrix of a certain dimension?!

Suppose I have a temperature matrix, T = zeros(Nz+1,Nt+1). Nz are number of elements in the z-axis and Nt are number of elements...

7 years ago | 1 answer | 0

Question

Getting error: Error using .* Matrix dimensions must agree. Please help. The code the given below.

Nx = 100;Ny = 20;Nt = 4000; x = 0:10/Nx:10; y = -1:2/Ny:1; t = 0:100/Nt:100; Dx = 10/Nx;Dy = 2/Ny;Dt = 10/Nt; a = 0...

7 years ago | 0 answers | 0

Question

Getting error: Error using .* Matrix dimensions must agree. Please help. The code the given below.

Nx = 100; Ny = 20; Nt = 400; x = 0:10/Nx:10; y = -1:2/Ny:1; t = 0:1/Nt:1; Dx = 10/Nx; % delta x Dy = ...

7 years ago | 0 answers | 0

Question

How to remove the following error: Attempted to access beta(2); index out of bounds because numel(beta)=1.

Here is my code. Any sort of help will be appreciated. a = @(x) -(x+3)/(x+1); b = @(x) (x+3)/((x+1).^2); f = @(x) 2*(...

7 years ago | 1 answer | 0

Question

Index must be a positive integer or logical.

I am getting the following error while running the code: Attempted to access R1_rk4(17501); index must be a positive integer ...

7 years ago | 3 answers | 0

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How to loop a discretely varying function in time?

How to run a function like this in a loop where time is increasing? Radius varying with time: First 2 seconds drops linearly,...

7 years ago | 0 answers | 0

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Find roots of this function!

How would I find the roots to this particular function? f(x) = mod((4 + x)/(4 - 3*x)) - exp(i*t) where; mod = modulus...

7 years ago | 0 answers | 0

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Form a matrix from elements of a second matrix

Suppose if I have a matrix like this: Time = [1;2;3;4;5;6;7;8;9;10] Diameter = [1;2;3;4;5;6;7;8;9;10] If I want to ...

7 years ago | 1 answer | 0

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How to specify a variable (using linspace) like this?

Distance between first and second point and the distance between second last and last point is 0.5h. All other distances between...

7 years ago | 2 answers | 0

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How to use ISNAN function?

How to write: if A(i+2,11) == NaN % Originally posted as: if (i+2,11) == NaN using ISNAN function?

7 years ago | 1 answer | 0

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Process Cells from Excel File

Suppose I have a spreadsheet like this: A B C 1: 0 45 87 2: 0 7 8 3: 1 65 68 4: 0 ...

7 years ago | 2 answers | 0