Answered

Nonlinear equation numerical solution

% params C = 1.2; D = 9420; E = -2.0; B = 0.1973; y0 =...

Nonlinear equation numerical solution

% params C = 1.2; D = 9420; E = -2.0; B = 0.1973; y0 =...

2 months ago | 0

Answered

Plotting a taylor series function of x^(1/3) centred at x=1728

One option is to use the built-in taylor function in symbolic math toolbox. If you want to use your strategy, there are some is...

Plotting a taylor series function of x^(1/3) centred at x=1728

One option is to use the built-in taylor function in symbolic math toolbox. If you want to use your strategy, there are some is...

3 months ago | 0

| accepted

Answered

Memory efficient alternative for meshgrid?

This is how to make the three-loop version analogous to the meshgrid version % some dummy values N = 300; x = linspace(1,10,N...

Memory efficient alternative for meshgrid?

This is how to make the three-loop version analogous to the meshgrid version % some dummy values N = 300; x = linspace(1,10,N...

3 months ago | 0

Answered

Sorting Equal Elements of Matrix into Groups in Cell Array

I had the same problem to detect isolated nodes in a graph: conncomp is the matlab command that gets the job done: % create the...

Sorting Equal Elements of Matrix into Groups in Cell Array

I had the same problem to detect isolated nodes in a graph: conncomp is the matlab command that gets the job done: % create the...

4 months ago | 0

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Answered

Error using / Matrix dimensions must agree...

f is a vector, as well as W. So you must use the dotted version of the division (that is ./ that performs the operation elementw...

Error using / Matrix dimensions must agree...

f is a vector, as well as W. So you must use the dotted version of the division (that is ./ that performs the operation elementw...

4 months ago | 0

Question

Copy Matlab Command Window without diary

Hi everyone, I would like to add an optional function command at the end of a script that logs the command window to a file. I...

4 months ago | 1 answer | 0

Answered

Is it possible to create a program on matlab that's works on android?

Sort of https://it.mathworks.com/help/supportpkg/android/run-on-target-hardware.html?s_tid=CRUX_lftnav

Is it possible to create a program on matlab that's works on android?

Sort of https://it.mathworks.com/help/supportpkg/android/run-on-target-hardware.html?s_tid=CRUX_lftnav

4 months ago | 0

Answered

How to improve my code speed (for loop)

By profiling, the most computational intensive operations are x=T*(probe-ut)'; y=T*(gallery-ut)'; That calculation is inside ...

How to improve my code speed (for loop)

By profiling, the most computational intensive operations are x=T*(probe-ut)'; y=T*(gallery-ut)'; That calculation is inside ...

4 months ago | 0

| accepted

Answered

How to optimize only 2 variables in an objective function with 3 variables?

In this case you can set the upper and lower bound for that specific variable to the same value. Maybe it is not efficient but i...

How to optimize only 2 variables in an objective function with 3 variables?

In this case you can set the upper and lower bound for that specific variable to the same value. Maybe it is not efficient but i...

4 months ago | 0

Answered

How to optimize only 2 variables in an objective function with 3 variables?

Why don't you remove theta from your objective function definition and call different_function inside function? function object...

How to optimize only 2 variables in an objective function with 3 variables?

Why don't you remove theta from your objective function definition and call different_function inside function? function object...

4 months ago | 0

Answered

How to change a column vector into a square a matrix?

Not as elegant as it could be but it works, especially for small matrices % matrix dimension n = 3; % your entries (here du...

How to change a column vector into a square a matrix?

Not as elegant as it could be but it works, especially for small matrices % matrix dimension n = 3; % your entries (here du...

4 months ago | 0

Answered

Calculate acceleration from velocity and time fron excel

acceleration = diff(data.Velocity)./diff(data.Time); Note that this vector has one entry less than the original ones, so you ma...

Calculate acceleration from velocity and time fron excel

acceleration = diff(data.Velocity)./diff(data.Time); Note that this vector has one entry less than the original ones, so you ma...

5 months ago | 0

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Answered

Subscripted assignment dimension mismatch.

You can use repmat and create a char array function bigstring = string_multiplication(str,N) bigstring = repmat(str,N,1); ...

Subscripted assignment dimension mismatch.

You can use repmat and create a char array function bigstring = string_multiplication(str,N) bigstring = repmat(str,N,1); ...

6 months ago | 0

Answered

Simulation errors when multiplying matrices

I start a new clean answer You don't have to use the index i inside your matrix like you are doing in your code: in that way yo...

Simulation errors when multiplying matrices

I start a new clean answer You don't have to use the index i inside your matrix like you are doing in your code: in that way yo...

7 months ago | 0

Answered

Solving Complex Matrix Operations

You can do this in a for loop or using arrayfun % your A vector A = rand(1,1001); % dummy vector % calculation of the matr...

Solving Complex Matrix Operations

You can do this in a for loop or using arrayfun % your A vector A = rand(1,1001); % dummy vector % calculation of the matr...

7 months ago | 0

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Answered

Replicate values in a matrix i-1 times

Quick and dirty for loop A=[1; 4; 8; 3; 2; 6] B = []; for i = 1:length(A) B = [B; repmat(A(i),i,1)]; end You can als...

Replicate values in a matrix i-1 times

Quick and dirty for loop A=[1; 4; 8; 3; 2; 6] B = []; for i = 1:length(A) B = [B; repmat(A(i),i,1)]; end You can als...

7 months ago | 0

Answered

Find independent variables that minimize function

If you have only lower and upper bounds, use them directly in fmincon % your function fun = @(x) ((x(1)-real(0.5*(x(1)-(sqrt(x...

Find independent variables that minimize function

If you have only lower and upper bounds, use them directly in fmincon % your function fun = @(x) ((x(1)-real(0.5*(x(1)-(sqrt(x...

7 months ago | 0

| accepted

Answered

Simulation errors when multiplying matrices

Inside the loop in the first instruction Vn(:,i) is 5x1 but T is 5x5. Matlab now (starting in 2016, I guess) implicitly expands ...

Simulation errors when multiplying matrices

Inside the loop in the first instruction Vn(:,i) is 5x1 but T is 5x5. Matlab now (starting in 2016, I guess) implicitly expands ...

7 months ago | 0

Answered

Weighted fit using fmincon

How about to repeat the samples of the points you want to weight more?

Weighted fit using fmincon

How about to repeat the samples of the points you want to weight more?

7 months ago | 0

| accepted

Answered

how to find the optimal value of a matrix that minimize a function?

If I understand correctly the problem can be recast to the following A*W = B*H = F; [a11 a12; a21 a22]*[w1 w2 0 0; 0 0 w3 w4] ...

how to find the optimal value of a matrix that minimize a function?

If I understand correctly the problem can be recast to the following A*W = B*H = F; [a11 a12; a21 a22]*[w1 w2 0 0; 0 0 w3 w4] ...

7 months ago | 0

| accepted

Answered

plot 2 3D vectors in Matlab

% vectors a = [1 2 -3]; b = [-3 12 -13]; % starting point C0 = [0 0 0]; % put vector in a matrix, to make the code more...

plot 2 3D vectors in Matlab

% vectors a = [1 2 -3]; b = [-3 12 -13]; % starting point C0 = [0 0 0]; % put vector in a matrix, to make the code more...

7 months ago | 0

Answered

Error using sparse Index into matrix must be positive.

Simply remove "-1" from the definition of R. randi returns pseudorandom integers between 1 and the first inupt. The entries of C...

Error using sparse Index into matrix must be positive.

Simply remove "-1" from the definition of R. randi returns pseudorandom integers between 1 and the first inupt. The entries of C...

7 months ago | 0

Answered

How to solve time and space deriavtive using ode45?

Have a look at pdepe: it solves 1-D parabolic and elliptic PDEs

How to solve time and space deriavtive using ode45?

Have a look at pdepe: it solves 1-D parabolic and elliptic PDEs

7 months ago | 0

Answered

Finite Difference Matrix Help

Edit: I changed my answer including a reference and the second order derivative The coefficients for central differences of dif...

Finite Difference Matrix Help

Edit: I changed my answer including a reference and the second order derivative The coefficients for central differences of dif...

7 months ago | 0

Answered

improved Euler integration scheme (possible code error) in matlab

I think it should be "-" p(1) = (-z(1)*(1-(z(2)))); p(2) = z(2)*(1-(z(1)));

improved Euler integration scheme (possible code error) in matlab

I think it should be "-" p(1) = (-z(1)*(1-(z(2)))); p(2) = z(2)*(1-(z(1)));

7 months ago | 0

Answered

Make entries of first row and column of matrix all equal to zero.

% nullify first col B(:,1) = 0; %nullify first row B(1,:) = 0;

Make entries of first row and column of matrix all equal to zero.

% nullify first col B(:,1) = 0; %nullify first row B(1,:) = 0;

8 months ago | 0

Answered

plot vector using complex numbers

You can use compass or quiver % your matrix A = [-3+4i;-2+5i;1+3i;6+2i;-1-8i]; % with compass figure compass(real(A),imag...

plot vector using complex numbers

You can use compass or quiver % your matrix A = [-3+4i;-2+5i;1+3i;6+2i;-1-8i]; % with compass figure compass(real(A),imag...

9 months ago | 0

Answered

constantly receiving an error undefined function or variable z when use solve

Polynomials with a degree greater than 4 do not have explicit solutions. You can use vpa syms x y f1 = y == x^3 f2 = x^2+y^2...

constantly receiving an error undefined function or variable z when use solve

Polynomials with a degree greater than 4 do not have explicit solutions. You can use vpa syms x y f1 = y == x^3 f2 = x^2+y^2...

9 months ago | 0

Answered

How to multiply only some column and rows for a given number?!

You are close to the answer, but you need to keep the first column % your matrix with data A = rand(2,21); % multiply all b...

How to multiply only some column and rows for a given number?!

You are close to the answer, but you need to keep the first column % your matrix with data A = rand(2,21); % multiply all b...

9 months ago | 1

Answered

Unstable derivative approximation when steps get too small

This is expected. Look here for details https://blogs.mathworks.com/cleve/2013/10/14/complex-step-differentiation/

Unstable derivative approximation when steps get too small

This is expected. Look here for details https://blogs.mathworks.com/cleve/2013/10/14/complex-step-differentiation/

9 months ago | 1