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# D_coder

26 total contributions since 2018

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Question

find peaks in a mesh plot
How do I find peaks in a mesh plot and also find its location on the mesh grid?

1 month ago | 2 answers | 0

### 2

Question

Thresholding based on energy
I have an image which is very sparse. I want to threshold the image by retaining a certain amount of energy. What is the most ef...

2 months ago | 1 answer | 0

### 1

Question

Is it possible to perform multiplication and update 'val' inside accumarray?
An accumarray function is defined as A = accumarray(subs,val,sz) I am running accumarray function in a loop , Is it po...

5 months ago | 0 answers | 0

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Question

Is there a function that performs element by element multiplication between two variables and stores in one of the variable by default?
I want to do this operation A = A.*B; Is there a function func(A, B) that multiplies A and B and saves the res...

5 months ago | 2 answers | 0

### 2

Question

Summing of non-zero elements of columns using indexing
I have idx, is there a way of using idx to make the sum(matrix,1) in the below code cheaper. In another words, is it possible to...

5 months ago | 2 answers | 0

### 2

HI friends, I need a matlab code of economic load dispatch with loss.
Here is one code which I found https://www.mathworks.com/matlabcentral/fileexchange/49456-economic-dispatch-including-losses He...

5 months ago | 0

Question

is there any faster way to operate a group of statements in a loop only once, than applying if else
for ......... statemets 1; statements 2: if iteration == 0 [value1,value2] = function(args1,args2); %dependent on ...

5 months ago | 1 answer | 0

### 1

How can I make derivatives with several variables?
You can try this a = a1^2*a2^2; diff(a,a1) + diff(a,a2); ans = 2*a1^2*a2 + 2*a1*a2^2

5 months ago | 1

Question

Sparse for element by element operation
If we want to perform the product of two sparse matrices or sparse and a full matrix , sparse function is very useful as it avoi...

5 months ago | 2 answers | 0

### 2

Question

I am working on saving computations and speeding up my Matlab code. Here's what I do Perform thresholding on an image and mak...

5 months ago | 3 answers | 0

### 3

Question

saving multiplications with zeros in a loop
%if true for i iterations Matrix = Matrix.*phase %Matrix has lot of zeros I want to skip multiplications with zero. Is it po...

5 months ago | 1 answer | 0

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Question

convert whole code to double
is it possible by anyway to convert whole code to double in a single step? For operations such as sparse single format and integ...

5 months ago | 1 answer | 0

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Question

Calculate values only once in the loop
Suppose I have a code running in a loop I have done some operations and I create a matrix in the loop, that matrix has the sam...

5 months ago | 2 answers | 0

### 2

Question

can anyone tell me an intuitive way of finding number of bins for histcounts function
The binning algorithm used by matlab is very expensive [N,edges] = histcounts(I) Instead I am looking for some different and co...

5 months ago | 1 answer | 0

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Question

why does method 1 result not equal to method 2 result even if both perform the same thing ?
a = [2 5 2 9 ; 3 2 5 0; 4 5 9 2; 1 6 1 5] threshold = 3 %function 1 z = 0; for n = 1: size(a,1) for m = 1...

5 months ago | 1 answer | 0

### 1

Question

How do I threshold the image automatically based on its energy content?
Say my threshold is taking in those components that constitute about 75% of energy of image and making the remaining as zero.How...

5 months ago | 1 answer | 0

### 1

Question

Histogram based thresholding for reduction in computation
i am planning to use histcounts () function for histogram based threshold We know that histogram is a plot of pixel intensity v...

6 months ago | 2 answers | 0

### 2

Question

Getting values of the histogram without actually plotting it

6 months ago | 1 answer | 0

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Question

Difference between graythresh and multithresh for one value of threshold.
graythresh(I) and multithresh(I,1) gives me different values even if both are based on otsu's method of thresholding Why?

6 months ago | 1 answer | 0

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Question

For a loop , to carry out element by element multiplication is bsxfun better than conventional element by element.
for number of iterations A = A.*B; %A and B both are complex end Will the loop be faster if I replace A.*B wit...

6 months ago | 3 answers | 1

### 3

Question

Complex matrix , make certain elements of real and imaginary as zero in a single line without storage
Suppose I have the following complex matrix s = rng; A = complex(randn(5,5),randn(5,5)); T = 0.15 How do I make bo...

6 months ago | 1 answer | 0

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Question

Given an image , how to efficiently (vectorization) make all the elements to zero except the one with information?
The image is scaled color version of absolute value of the matrix.

6 months ago | 2 answers | 0

### 2

Question

Multiplication of Sparse complex matrix and a full matrix
Let A be a sparse matrix and B be a full matrix . C = A.*B. Will multiplication of elements of B corresponding to the zero elem...

6 months ago | 1 answer | 0

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Question

Sparse matrix and savings
I have a complex matrix which has non zero values only in specific region of the matrix. And most of the remaining part is equal...

6 months ago | 1 answer | 0

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Question

How do I threshold only real part of a complex matrix?
For a complex matrix how do I threshold only the real part of its elements to zero if I have complex matrix A, |A(real(A)>0.5)=...

6 months ago | 1 answer | 0