Community Profile # Douglas Brenner

Active since 2016

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Matlab crashes but Octave doesn't
Give that man a cigar and thank you very much. pinv(A)*b work as I suspect doing the LU decomposition manually would.

más de 3 años ago | 0

Question

Matlab crashes but Octave doesn't
The program below runs in Octave but crashes Matlab 2014. Mathworks won't help because my contract has run out. Any ideas would ...

más de 3 años ago | 3 answers | 0

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creating a vector where each element needs to be calculated before hand
Can I creat Z in a single statement which doesn't require explicit calculation of each element or should I just use a loop? Z =...

más de 3 años ago | 1 answer | 0

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Question

Creating a matrix one row at a time
In each iteration of a loop I create a row vector Y = [1,2,3,4,5]; then I want to add the Y's to a matrix one line at a time;...

más de 3 años ago | 2 answers | 0

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help with fitlm (least squares fit)
I could try a Gaussian fit. That would work for me. Do you have an example for that? Thanks.

más de 3 años ago | 0

help with fitlm (least squares fit)
Your demo crashed it as well.

más de 3 años ago | 0

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help with fitlm (least squares fit)
X = [1,2,3,4,5] Y = [1,5,6,4,2] yFit = polyfit(X,Y, 2) Matlab itself crashed.

más de 3 años ago | 0

Question

help with fitlm (least squares fit)
I don't understand how to use fitlm if indeed that's the right function to use. I want to fit 5 sets of data to the function y ...

más de 3 años ago | 3 answers | 0

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Why would circshift stop working.
I had been transposing matrics and released this morning as I was waking that this must have been the problem. Thanks.

más de 3 años ago | 0

Question

Why would circshift stop working.
There is no evidence that circshift is working. The two plots are the same whereas yesterday a clear shift in the plots can be s...

más de 3 años ago | 3 answers | 0

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matrix multiplication dimension issues
Found the answer. n is not the number of points in a spectrum but the number of spectra. Thanks for trying

más de 3 años ago | 0

matrix multiplication dimension issues
The basic science is to take two spectra and perform a 2d cross correlation resulting in a real and a complex matrix. They shoul...

más de 3 años ago | 0

Question

matrix multiplication dimension issues
I have an article which I'm trying to follow. It calculates two matricies that I called synch and async. I read two files into...

más de 3 años ago | 3 answers | 0

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Replacing for loops with matrix math.
How can I simplify this code. I.e remove the loops and replace them with matrix math. for i=1:3 for j = i:num_pts - ...

más de 3 años ago | 1 answer | 0

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Question

Getting off diagonals after calculating a correlation matrix
The code below gives the first off diagonals of the correlation computation in line 6. How do I get the others? testm1 = [1...

más de 3 años ago | 0 answers | 0

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reducing number of operations in matrix multiplication
Clearly but that was the suggested solution. Trying for i=1:2 diags1{i} = testm(i+1:num_pts-i-1 ,2).*testm(1:num_pts-i-1,2...

más de 3 años ago | 0

reducing number of operations in matrix multiplication
testm = [1,2,3,4,5;2,4,5,7,10] num_pts = 5; testm = transpose(testm) corr = testm(:,2)*testm(:,2)' diag(...

más de 3 años ago | 0

Question

reducing number of operations in matrix multiplication
I want to perform the follow operation: synch = spect1(1:num_pts ,2)*spect2(1:num_pts,2)'; The problem is that num_pts > 300,0...

más de 3 años ago | 2 answers | 0

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Question

Why does this loops produce a matrix?
code waves = [393.029, 414.386, 427.176, 516.748, 526.953, 640.000]; l = length(waves); for i = 1:l L = wave...

más de 3 años ago | 1 answer | 0

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dimension error with * operator
The paper from which I got the code uses * and that works in this line: synch = C1(:)*C1(:)'/(delta-2). Not only do I not get ...

más de 3 años ago | 0

Question

dimension error with * operator
This line of code: asynch = C1(:)*N(:)*C(:)'/(delta-2) throws an error: Error using * Inner matrix dimensions must agree. Th...

más de 3 años ago | 3 answers | 0

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error trying to run xcorr2.
This is the error: Cell contents reference from a non-cell array object. Error in cell2mat (line 42) But if I try a different...

más de 3 años ago | 0

Question

error trying to run xcorr2.
This is my code D1 = cell2mat(data1{2}); %D1 and D2 are 1x3 cells of doubles D2 = cell2mat(data2{2}); c = xcorr2(D1,D2); It ...

más de 3 años ago | 1 answer | 0

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Getting non-existent pixel values
Didn't work Index exceeds matrix dimensions. Error in stddev (line 51) greenChannel = b(:, :, 2); Is there a green pla...

más de 5 años ago | 0

Question

Getting non-existent pixel values
After the following code, an image is displayed. It is black, white and red. However, if I use hpimpixelinfo(2) on the image I ...

más de 5 años ago | 2 answers | 0

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image processing algorithm for filling
I am going to try but in the meantime if anybody wants to help ... I have a 2-D image in black, white and red. Going across e...

más de 5 años ago | 0 answers | 0

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Question

using greythresh and im2bw
Figure 1 is great but BW is all black. Thoughts? Thanks figure (1) scaled = 255 * width/MAX; imshow(uint8(scal...

más de 5 años ago | 1 answer | 0

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What does this error for hist mean?
Attempt to execute SCRIPT hist as a function: /Users/douglasbrenner/Documents/MATLAB/hist.m Error in extractedge (line 3...

más de 5 años ago | 2 answers | 0