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# Mahdi

### University of Waterloo

Last seen: 3 Monate ago Active since 2013

MATLAB Enthusiast.
Chemical Engineering Student; interested in computation and modelling.
Enjoys Snowboarding.

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Question

How can I make this code more efficient?
Hello, Because of the large number of differential equations I'm trying to solve, I would like to make this code more efficie...

etwa 6 Jahre ago | 1 answer | 0

### 1

X and Y matrix of size:1x68.this code works well.but when command " plot(X,Y,'ro', x,y,'-b',xt,yt,'--g');" shifted outside for loop; plot for last value of xt and yt How to store all values of xt and yt outside for loop?
Change the the lines to: xt(i,:) = X0+(0.1*(max(X)-min(X))*[-1 0 1]); and yt(i,:) = y(k) + m(k)*(0.1*(max(X)-min(...

mehr als 7 Jahre ago | 0

Cubic spline interpolation with second derivative at ends as zero
Doesn't the <http://www.mathworks.com/help/matlab/ref/spline.html spline> function work?

mehr als 7 Jahre ago | 0

i want some links to basic matlab problem solving
The <http://www.mathworks.com/matlabcentral/cody/?s_tid=gn_mlc_cody cody> problems give some quick practice.

mehr als 7 Jahre ago | 0

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How i save the value of c in deach loop and sum these value after each value then using value in another eq outside loop??
Say E=3; for i=1:3 A(i)=x((i-1)*3+1); B(i)=x((i-1)*3+2); C(i)=x((i-1)*3+3); Z(i)=A*B+C*A; W=E-sum(C); end

mehr als 7 Jahre ago | 0

How do I stack many files together into one?
One way of doing this name='SpectraA' for i=1:5 #Let's say you have SpectraA1....SpectraA5 Filename=strcat(name, num2str(...

mehr als 7 Jahre ago | 0

matlab exe file to run as admin
Do you have the shortcut? You can right click --> Properties --> Location and find it. Even there, you can right click the short...

mehr als 7 Jahre ago | 0

what's the program mistake?
Try this? clear all clc; syms x A=[x 2 1;1 0 -x;5 1 x]; b=det(A) r=eval(solve(b==0))

mehr als 7 Jahre ago | 0

How to make loop and sum the result ??
for i=1:3 A(i)=x((i-1)*3+1); B(i)=x((i-1)*3+2); C(i)=x((i-1)*3+3); R(i)=A^2+B^3+A*c; end Summation=sum(C);

mehr als 7 Jahre ago | 0

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Vector indexing inefficiency question.
Have you looked at <http://www.mathworks.com/help/matlab/ref/perms.html perms> built-in function? I'm sure you can manipulate to...

mehr als 7 Jahre ago | 0

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I face the error of "In an assignment A(I) = B, the number of elements in B and I must be the same" when i want to create a loop a matrix. my simple short code given below, plz help me?
p(i) is one element, but you are trying to tell it to store multiple values, one of the following would fix your problem (Just r...

mehr als 7 Jahre ago | 0

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Extract a row of multiple files in loop
I didn't look through the whole code, but based on the error, try the following: line(i) =line(i)+Signal(pixel_line,:); ...

mehr als 7 Jahre ago | 0

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Have you looked at the <http://www.mathworks.com/help/matlab/ref/xlsread.html xlsread> documentation? It tells you exactly how t...

mehr als 7 Jahre ago | 1

Extract xdata and ydata from hggroup
If you have the .fig file, you can just follow this <http://www.mathworks.com/matlabcentral/answers/100687-how-do-i-extract-data...

mehr als 7 Jahre ago | 0

How to make a vector where each element=5 and 100 elements long?
What you did produces a vector that starts at 1 and goes up by 5 till it reaches 100 elements. If that was your goal, then it's ...

mehr als 7 Jahre ago | 0

Question

Why is 10^5 more expensive than 10e5?
As Jan mentioned in this <http://www.mathworks.com/matlabcentral/answers/57638#comment_119764 post>, what's the reason behind it...

mehr als 7 Jahre ago | 1 answer | 1

### 1

i need to fix errors in interface
This line: filename('waad s.jpg') is not a valid code to put into MATLAB. I am not sure what you're trying to do, but th...

mehr als 7 Jahre ago | 0

change the number of digits after decimal point
You can use the <http://www.mathworks.com/help/matlab/ref/sprintf.html sprintf> or the <http://www.mathworks.com/help/matlab/ref...

mehr als 7 Jahre ago | 1

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plot multipe figures with diferents color
You can iterate through each point with a for loop ColoursToUse=['r' 'b' 'g' 'c'] figure(1) hold on for i=1:4 plot3(mx(...

mehr als 7 Jahre ago | 0

how can I direct a user to the script end script skipping intermediate?
You can easily just add an if statement for the code to only apply based on what you input into it. For example, let's say I hav...

mehr als 7 Jahre ago | 0

Generation of random numbers
I think what you're trying to do is done using randn, so that dd=(10^(4) - 10^(-4)).*randn(1000,1) + 10^(-4) hist(dd,100...

mehr als 7 Jahre ago | 0

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what 's different between axis square and axis equal in matlab ?
From this <http://www.mathworks.com/help/matlab/ref/axis.html page>: axis equal sets the aspect ratio so that the data units ...

mehr als 7 Jahre ago | 3

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I want to make a function with save option.
The problem is in the way you're handling the variables. Basically, the inputs to your function in this case are taken as variab...

mehr als 7 Jahre ago | 0

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How to use legend command
Is the loop still telling the figure to plot even if there isn't any data recorded? You have a few ways around it: The first...

mehr als 7 Jahre ago | 0

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How to plot multiple iterations on the same axes?
figure; hold on for i=1:length(s_x_index) f_value(i)=f_x # This is the value that you get from each iteration end plot(s_x...

mehr als 7 Jahre ago | 0

Convert a Roman numeral to its decimal equivalent for first ten roman numerals?
Have a look at this <http://www.mathworks.com/matlabcentral/fileexchange/26161-roman2num-and-num2roman--modern-roman-numerals fu...

mehr als 7 Jahre ago | 0

How May I import date/time from Excel?

mehr als 7 Jahre ago | 0

How come i get different output answers with the same matlab version, the same code installed on two different computers?
I am assuming that your problem is ill-conditioned or is very sensitive and depends greatly on the numbers from each step (or th...

mehr als 7 Jahre ago | 0

| accepted