Answered

Is there a way of removing these for loops to speed up my code?

Profiling your code it comes up that the most demanding routine is the Green function calculation, with 0.374s: I have rewrit...

Is there a way of removing these for loops to speed up my code?

Profiling your code it comes up that the most demanding routine is the Green function calculation, with 0.374s: I have rewrit...

17 hours ago | 0

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Answered

Fit data to sawtooth shape

As usual, John is right. I tried to implement a strategy to fit sampled data with noise with a sawtooth waveform. I am pretty pr...

Fit data to sawtooth shape

As usual, John is right. I tried to implement a strategy to fit sampled data with noise with a sawtooth waveform. I am pretty pr...

1 day ago | 0

Answered

Find position of a column given a specified array

idx = find(ismember([Mritsum(:) BrB(:)],point,'rows'))

Find position of a column given a specified array

idx = find(ismember([Mritsum(:) BrB(:)],point,'rows'))

1 day ago | 0

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Answered

How do i plot a 3D structure as in the attached picture?

I share with you a couple of function that I use to plot grounding grids. They are attached. Then you can use the following scri...

How do i plot a 3D structure as in the attached picture?

I share with you a couple of function that I use to plot grounding grids. They are attached. Then you can use the following scri...

1 day ago | 0

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Answered

How to assign to an already 3d surface a colormap based on a set of values ?

Not sure if I have understood correctly. I try. I assume that you have the temperature plot as 2d matrix, as required by surf, b...

How to assign to an already 3d surface a colormap based on a set of values ?

Not sure if I have understood correctly. I try. I assume that you have the temperature plot as 2d matrix, as required by surf, b...

2 days ago | 1

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Answered

How can I plot this function

You may use surf % define a suitable number of x and y divisions. Here I used 200 x = linspace(0,10,200); y = linspace(1,30,2...

How can I plot this function

You may use surf % define a suitable number of x and y divisions. Here I used 200 x = linspace(0,10,200); y = linspace(1,30,2...

2 days ago | 0

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Answered

How can I extract a signal between zero up-crossings

You can take a look at this post, where zero crossing is discussed in details https://it.mathworks.com/matlabcentral/answers/26...

How can I extract a signal between zero up-crossings

You can take a look at this post, where zero crossing is discussed in details https://it.mathworks.com/matlabcentral/answers/26...

3 days ago | 0

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Answered

Unique ID Min and Max with multiple values per Unique ID

Tessa, look if this fits your problem % col vector M1 = [10 17 201 333 1000].'; M2 = [10 10 17 17 17 201 1000; 0.1 69 1.7 33...

Unique ID Min and Max with multiple values per Unique ID

Tessa, look if this fits your problem % col vector M1 = [10 17 201 333 1000].'; M2 = [10 10 17 17 17 201 1000; 0.1 69 1.7 33...

3 days ago | 0

Answered

split dataset with probability weights

datasample has a two outputs, where the second is the index to the selected data in your npop1. So: [rw1,idSelected] = datasamp...

split dataset with probability weights

datasample has a two outputs, where the second is the index to the selected data in your npop1. So: [rw1,idSelected] = datasamp...

4 days ago | 0

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Answered

select certain matrix elements

You can simply concatenate your ranges using square brackets: A([1:10 20:30],1)

select certain matrix elements

You can simply concatenate your ranges using square brackets: A([1:10 20:30],1)

4 days ago | 0

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Answered

If statement with or condition

if any(settimana < bdr) ... else ... end

If statement with or condition

if any(settimana < bdr) ... else ... end

4 days ago | 0

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Answered

Setting min value of variables within a function

Maybe I don't understand correctly: if you want to set all negative entries of fval to 0 you can add fval(fval < 0) = 0; at th...

Setting min value of variables within a function

Maybe I don't understand correctly: if you want to set all negative entries of fval to 0 you can add fval(fval < 0) = 0; at th...

4 days ago | 0

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Answered

How do I make a 21x21 array from the center of a 200x150 array?

% dimensions n = 21; % rows m = 21; % cols % load image A = imread('grayscale.png'); % find center coordinate iCen...

How do I make a 21x21 array from the center of a 200x150 array?

% dimensions n = 21; % rows m = 21; % cols % load image A = imread('grayscale.png'); % find center coordinate iCen...

4 days ago | 0

Answered

Create a matrix on the basis of other matrix

% your data SPI = [2 3 4 8 11 13 14 15 16 18 19 20]; AA = [1 2 3 4 0 11 14 15; 0 0 0 8 13 16 0 0; 0 0 0 0 ...

Create a matrix on the basis of other matrix

% your data SPI = [2 3 4 8 11 13 14 15 16 18 19 20]; AA = [1 2 3 4 0 11 14 15; 0 0 0 8 13 16 0 0; 0 0 0 0 ...

4 days ago | 0

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Answered

How to i produce a signal which is a combination of three sinusoidal signal oscillate a frequency?

% frequencies f = [10 100 200]; % random amplitudes V = rand(3,1); % random phase phi = 2*pi*rand(3,1); % time axis ...

How to i produce a signal which is a combination of three sinusoidal signal oscillate a frequency?

% frequencies f = [10 100 200]; % random amplitudes V = rand(3,1); % random phase phi = 2*pi*rand(3,1); % time axis ...

4 days ago | 0

Answered

Create an array from others matrix

You can just append the matrices as they come. a=100; b=5; N=8; % inital empty matrix PM = []; % your loop for sec=1:a ...

Create an array from others matrix

You can just append the matrices as they come. a=100; b=5; N=8; % inital empty matrix PM = []; % your loop for sec=1:a ...

4 days ago | 0

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Answered

Problem with while loop

% make matrices of the same length n1 = size(S1,1); n2 = size(S2,1); S1 = S1(min([n1,n2]),:); S2 = S2(min([n1,n2]),:); % ...

Problem with while loop

% make matrices of the same length n1 = size(S1,1); n2 = size(S2,1); S1 = S1(min([n1,n2]),:); S2 = S2(min([n1,n2]),:); % ...

4 days ago | 0

Answered

Create a matrix on the basis of other matrix

Under the assumption that the "diversity" contains the same number of entries each row for i = 1:size(M,2) b(:,i) = unique...

Create a matrix on the basis of other matrix

Under the assumption that the "diversity" contains the same number of entries each row for i = 1:size(M,2) b(:,i) = unique...

4 days ago | 0

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Answered

problem with fzero in my code

your fun is neither acceppting nor using inputs You should write the symbolic function like this fun = @(x)cos(x); x0 = fzero...

problem with fzero in my code

your fun is neither acceppting nor using inputs You should write the symbolic function like this fun = @(x)cos(x); x0 = fzero...

5 days ago | 0

Answered

how can i slove this proplem "- The vector V is given by V=[2 8 7 3 1 0 8 9]. Write down a single instruction to produce a vector that contains 1 in the place of the odd numbers and -1 in the place of the even numbers."

A suggestion: you can easily find the reminder of the division by 2, so that even numers have reminder 0 and odd numbers reminde...

how can i slove this proplem "- The vector V is given by V=[2 8 7 3 1 0 8 9]. Write down a single instruction to produce a vector that contains 1 in the place of the odd numbers and -1 in the place of the even numbers."

A suggestion: you can easily find the reminder of the division by 2, so that even numers have reminder 0 and odd numbers reminde...

5 days ago | 0

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Answered

Operands to the || and && operators must be convertible to logical scalar values.

If you work with arrays, use the single & and not &&

Operands to the || and && operators must be convertible to logical scalar values.

If you work with arrays, use the single & and not &&

5 days ago | 0

Answered

How to use fzero in a loop to obtain the first 3 positve solutions for cos3x=sin3x?

fzero gives you only one solution. In case of multiple roots, the choice depends on the initial choice and on the algorithm. If ...

How to use fzero in a loop to obtain the first 3 positve solutions for cos3x=sin3x?

fzero gives you only one solution. In case of multiple roots, the choice depends on the initial choice and on the algorithm. If ...

5 days ago | 0

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Answered

how to write a code to extract a positive latitude value for the corresponding positive longitudinal cell value

% filter idx = longitudinal >= 50 & longitudinal <= 100 & latitude >= 0 & latitude <= 40; % selection longitudinal2 = longi...

how to write a code to extract a positive latitude value for the corresponding positive longitudinal cell value

% filter idx = longitudinal >= 50 & longitudinal <= 100 & latitude >= 0 & latitude <= 40; % selection longitudinal2 = longi...

5 days ago | 0

Answered

Making a vector out of all even and odd numbers using for, if

This happens because the original vector contains random numbers that change every time you run the code. So, also the number of...

Making a vector out of all even and odd numbers using for, if

This happens because the original vector contains random numbers that change every time you run the code. So, also the number of...

5 days ago | 0

Answered

Error using plot Vectors must be the same length.

Some comments 1) Q is defined twice as symbolic variable, but it is actually an array 2) in the first loop N = 4, so length(t)...

Error using plot Vectors must be the same length.

Some comments 1) Q is defined twice as symbolic variable, but it is actually an array 2) in the first loop N = 4, so length(t)...

6 days ago | 0

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Answered

Optimisation of function containing matrix

While waiting for the data, I try to solve one of the questions. you can set the missing constraint as x1-x2 = 0 x2-x3 = 0 .....

Optimisation of function containing matrix

While waiting for the data, I try to solve one of the questions. you can set the missing constraint as x1-x2 = 0 x2-x3 = 0 .....

8 days ago | 0

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Answered

How to plot points on a line

I suggest you to check hold on, and the LineSpec of the command plot % your data new = rand(5,1); % open figure and retain ...

How to plot points on a line

I suggest you to check hold on, and the LineSpec of the command plot % your data new = rand(5,1); % open figure and retain ...

8 days ago | 1

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Answered

How to break an image into blocks?

Three assumprions 1) the image is a 2d matrix 2) the row/cols have 64x3, 3x64 and 3x3 blocks 3) you want 10 sub images, not 1...

How to break an image into blocks?

Three assumprions 1) the image is a 2d matrix 2) the row/cols have 64x3, 3x64 and 3x3 blocks 3) you want 10 sub images, not 1...

8 days ago | 0

Answered

Optimization problem using external program

I can figure out two solutions 1) check if the simulation program has API for running it from "outside". In this case, make ref...

Optimization problem using external program

I can figure out two solutions 1) check if the simulation program has API for running it from "outside". In this case, make ref...

8 days ago | 0

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Answered

Intersections between 2 graphs

Try this software on fex https://it.mathworks.com/matlabcentral/fileexchange/11837-fast-and-robust-curve-intersections

Intersections between 2 graphs

Try this software on fex https://it.mathworks.com/matlabcentral/fileexchange/11837-fast-and-robust-curve-intersections

8 days ago | 0

| accepted