Community Profile

# Ahmed A. Selman

89 total contributions since 2013

Ph.D. in theoretical nuclear physics, author of four books and lecturer at the College of Science-University of Baghdad since 2008. Interested with image processing applications in astronomy mainly. I begun using Matab since the year 2000 (I think it was ver.5.), and still there is much to learn about.
Professional Interests: Theoretical Physics

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dec2any(x,n)
Decimal (base 10) number to any (base 2 to 10) converion function.

Submitted

dec2senary(num)
Decimal (base 10) number to senary (base 6) converion function.

Help naming text file according to user input
Just add the extension you like to the variable (fileName), as prompt = 'Please enter the file name: '; fileName = input(...

mehr als 6 Jahre ago | 3

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how to find the second order partial derivative of an image?
See older and similar question here: <http://www.mathworks.com/matlabcentral/answers/67893>

fast 7 Jahre ago | 0

Reshape array for 256 by 256 matrix showing 16 by 256

fast 7 Jahre ago | 0

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Save 512x512 matrix to text file
This code works perfectly. To check it add the following at the very end of the above code: fid = fopen('Mymatrix.txt','r'...

fast 7 Jahre ago | 0

solve 2 equation of 2 unknown
Use the code instead: clc clear syms theta3 r1 %sind(theta3) % NOT NEEDED r2=3; r3=3.927; r4=0.335; ...

fast 7 Jahre ago | 1

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extracting submatrices from cell
Try the same example with: X={1, 'a'; 'b', 3.14}; K1=X(2,:) [K21 K22]=X{2,:} Then use whos to...

fast 7 Jahre ago | 0

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How to identify boundaries of shapes in an image using the change in color
There are few files in the file-exchange <http://www.mathworks.com/matlabcentral/fileexchange/> so do some search there, you mig...

fast 7 Jahre ago | 0

error message using polynom
A polynomial P(x) is said to be (badly conditioned) when a small variances of x leads to large errors of P, causing unstable err...

fast 7 Jahre ago | 0

Creating a matrix with matrices on the sub and super diagonals
Use the command (diag) for creating a (main) diagonal matrix from a vector A, and the command (spdiags) to create sub- and super...

fast 7 Jahre ago | 0

Picking out a value from a Vector in a Loop iteration
Within your same code: ... plot(Y(:,1),Y(:,2),'o'); z=zeros(1,length(X)); % Add this for i = 1:length(X) f...

fast 7 Jahre ago | 0

More help with probability...
Just pay attention to how you use function call inside a program. Either you have two files as stated above, or use one main (ca...

fast 7 Jahre ago | 0

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How to plot with a logarithmic scale?
semilogx(x,y)

fast 7 Jahre ago | 2

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how to solve loops conditions ??
#1) Using for loops only: clear k=0; for i=1:6 for j=1:5 k=k+1; A(i,j)=k; end end ...

fast 7 Jahre ago | 0

Submitted

Blancmange-Takagi Function
Used to plot the Blancmange-Takagi function of order (w) and range (x).

Symbolic expressions: abs(x^(1/3)) =?= abs(x)^(1/3)
Some times we get confused between mathematics and programming, it is an often thing. Yet, mathematics means logic, programs try...

fast 7 Jahre ago | 0

how to write a .dat file in matlab?
The obvious method is to construct a loop to read filenames, inside it, open and read, then accumulate the data content in some ...

fast 7 Jahre ago | 0

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Reading many files in one loop

fast 7 Jahre ago | 0

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How to read a text file line by line?
Try selecting one dimension a time for each line, e.g., ... time=fscanf(fID,'%g',[1 1:2:inf]); acce=fscanf(fID,'%g',[...

fast 7 Jahre ago | 0

Obtaning a matrix with the right indexes
Try this out to see if it solves the issue: clear clc N=20; %for example H=sym(zeros(N,4)); B=1:N; ...

fast 7 Jahre ago | 0

How to create a nested for loop to create a mesh plot
I'm not sure what are your conditions (in the if statements), but you used (y1) as a matrix index which cannot be made unless (y...

fast 7 Jahre ago | 0

If all variables other than (y) are known, then let's write some notes here: 1) Try to first define the variables, namely: kw...

fast 7 Jahre ago | 0

Issue with writing multiple variable to excel sheet
It is not practical to write a single line in an excel file, for a large amount of data or inside a long-time running loop. If y...

fast 7 Jahre ago | 1

Submitted

LVPermute
A simple (Line Vector Permutation) function.

while loop question number 2
In such a case, using a while loop cannot do the job, but an if statement can. So, I think this is what are you looking for (con...

fast 7 Jahre ago | 0

How to plot a complicated function
It is the same code you wrote, only add loops over c and tau, and use the function (ezplot) to plot a function handle. And DO NO...

fast 7 Jahre ago | 0

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how to code probability in general??
First what is magic(2)? I thought the smallest magic matrix comes (3-by-3) since Magic (2) doesn't satisfy the condition (sum ea...

fast 7 Jahre ago | 0

| accepted