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How to insert a matrix into a matrix
a = your 2x2 marix b = your 4x4 matrix b(3:4,1:2) = a;

9 years ago | 2

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Problem in if-else if-else structure
You can't compare to NaN with the == operator, since NaN is not equal to anything (including itself). You must use the isnan fun...

9 years ago | 1

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sparse function cannot get integer arrays for the indices
The sparse matrix storage has always been the following internally as far as I know (I think back to R2006a is all I have checke...

9 years ago | 2

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how to save the dir output?
dir_list = dir('/D/myfolder');

9 years ago | 0

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Finding roots of a polynomial
An n'th order polynomial will have n roots, some of which may be repeated or complex. You have a 3rd order polynomial which will...

9 years ago | 0

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Answered
In an assignment A(:) = B, the number of elements in A and B must be the same.
Index your t variable inside the loop. E.g., dydt=-0.5.*exp(0.5.*t(i)).*sin(5.*t(i))+5.*exp(0.5.*t(i)).*cos(5.*t(i))+yi; ...

9 years ago | 0

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Estimating pi using while loop for specific tolerence.
For starters, if you are taking the tolerance out to 12 digits and beyond, you need to use a more accurate value of pi for your ...

9 years ago | 0

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Answered
Creating two random matrices
E.g., % random matrix M = rand(4,8); % normalize per the 4-element sums M(:,1:4) = bsxfun(@rdivide,M(:,1:4),sum(M(...

9 years ago | 1

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Answered
how do I square a column in a matrix?
X = your 7x3 matrix X(:,3) = X(:,3).^2; % replace 3rd column with its square (element-wise) Note the dot in front of th...

9 years ago | 0

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Answered
How to use command function?
I would advise using a cell array for this instead of many separately named variables. E.g., predictor = cell(15,1); for...

9 years ago | 0

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Answered
Newbie needing to create matrix elements dependent on other elements
A = your Nx6 matrix A(:,7) = sqrt(sum(A(:,1:3).*A(:,1:3),2)); % The RSS of the 1st 3 columns by row

9 years ago | 0

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Answered
I have a cell (NewCell {1,1}) with 1 column and many rows, each row has or '0' or []. If its '0', I want to make a comparison; if its the other thing, i want a 'V'.
elseif isempty(NewCell{1,1}{k}) The problem you are having is that the result of NewCell{1,1}{k} ~= '0' is empty in that br...

9 years ago | 0

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Incorrect matrix substitution with ML2016b
You don't show your code, but my guess is you did one of the element-wise operations that now has scalar expansion built in. E.g...

9 years ago | 0

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Answered
Why can't i plot this equation?
Use element-wise divide operator ./ instead of matrix divide operator / f=@(x)((1+x.^2-1.5*x.^3+0.5*x.^4)./(1+x.^4))

9 years ago | 0

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Answered
Could someone please explain what is wrong in this simple code
Is this what you want? cm = @(x,Dt) exp((-x.^2)/(4*Dt))/2*(pi*Dt)^(1/2); Dt = [1/16,1/4,1]; x = -5:.01:5; for k=1:...

9 years ago | 1

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Answered
Matrix dimensions must agree error
Looks like you want to do a string compare in these lines: if strcmp(raw{k,1},'Time, s') : if strc...

9 years ago | 0

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Answered
How can I turn a data vector into a matrix of rows with the same vector?
If you just need to do the subraction: result = bsxfun(@minus,A,b); If you need your B for some other reason also, then:...

9 years ago | 0

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Mean for 4D
umean = squeeze(mean(u,2));

9 years ago | 0

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Answered
Variable B in a table (type = double) needs to calculated based on Variable A in the same table (type = double), but the key is that Variable B is calculated based on the value of Variable A in both the current row and the previous row. How please ?
When n=1 you are using an index of 0 which will cause an error. What do you want to do for the 1st element since there is no 0't...

9 years ago | 0

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exceeds matrix dimensions error. How to solve
Enter this at the command line dbstop if error Then run your code. When the error is encountered, the program will pause...

9 years ago | 0

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x = 10*((length00/2)-floor(length00/2)); what does this mean?
Did you try it to see what it does? E.g., >> length00 = 12.34 length00 = 12.3400 >> length00/2 ans = ...

9 years ago | 1

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modifying the value of angle of a complex number?
z = your complex number a+bi e = your new angle znew = abs(z).*exp(1i*e);

9 years ago | 1

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Computationally efficient Matrix-Vector multiplication
I am not following your suggestion. The link in question refers to an element-wise multiplication, which results in N^2 unique i...

9 years ago | 0

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mexGetPr error when freeing the data
These lines show that rlist and r come from the MATLAB Memory Manager: rlist=mxGetPr(prhs[8]); r=mxGetPr(prhs[9]);...

9 years ago | 0

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Answered
2d matrix to 3d matrix conversion with signals
x = your 900000x250 matrix xnew = reshape(x',250,150000,6);

9 years ago | 0

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Volume of a cylinder
Seems like you have this information: V1 = pi*(r1^2)*h1 <-- this is all known V2 = 1.2 * V1 <-- this is given ...

9 years ago | 1

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Answered
Extract elements from a heap
I am assuming you have a typo in your code above and are really starting with keys in sorted _"consistent"_ order ... i.e., I as...

9 years ago | 1

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Answered
Matlab crashing when evaluating mex
Here is some sample code for you to peruse. It takes a 2D matrix input and writes the input values to the screen using various ...

9 years ago | 1

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Answered
If I have a matrix of 100 rows by 5 columns, how can I make it a 1 row x 500 column matrix, where each row (1x5) is placed one after the other to make a 1x500 matrix?
datanew = reshape(data',1,[]);

9 years ago | 0

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Answered
Problem With Graph In Function
E.g., something like this to get you started T = 1:1:t+1; m = size(X,1); figure(1); G = plot(T',X'); legend([re...

9 years ago | 0

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