Matlab Definition and 1000 Threads

  1. jdawg

    Matlab: Problem with function inputs

    Homework Statement The volume V of a liquid in a partially filled ellipsoid shaped tank is given by V = (pi/3)*(3*a-h)*(((b^2)*(h^2))/(a^2)) Develop an M-file to create a plot of volume versus depth. Here are the first few lines: function myellipsoid(a,b,plot_title) % Volume of horizontal...
  2. M

    MATLAB Number formats in Matlab [not to use e symbol]

    When I write 1.516*10^-5 in Matlab it gives 1.516000000000000e-05 but I do not want to use e symbol. So which format should I use. I could use format bank but it has only two digits. I need more digits. Would you like to help me. Thank you.
  3. M

    MATLAB Greek symbols on Matlab workspace

    Can we use Greek symbols on Matlab workspace? If so, how can we use them? I have made a search, most of the replies on the net was that Greek symbols cannot be used on workspace. Thank you.
  4. M

    MATLAB Too little appearance of symbols and numbers in matlab

    Hi, When I using Matlab 2008, the symbols and numbers were big enough to see but now I use Matlab 2013 but symbols and numbers or what I write is too little. How can I make them bigger? Thank you.
  5. L

    MATLAB How can I use MATLAB to take the derivative of an experimental plot?

    In MATLAB, what does ./ mean? Also, I would like to take the derivative of an experimental plot. How do I do so?
  6. jdawg

    Help with Plotting Data & Function in Matlab

    Homework Statement I'm a little lost on how to plot this data and function. I included the homework question and my attempt at plotting in the attached picture. I'm pretty sure what I have is completely wrong and I honestly don't have much of an understanding of matlab, so the more you dumb it...
  7. sounouhid

    MATLAB Fit Experimental Data with MATLAB: Best Practices

    Hello everyone help please I need to fit experimental data with a theoretical model using the MATLAB software what is the best way to do it? thx for advance
  8. srinaath

    Generating SPWM using arduino-simulink environment

    hi all...am trying to generate sinusoidal pulse width modulation using arduino-simulink for my inverter board...I simulated the SPWM logic in simulink, then installed the required support package for arduino-simulink...but i am facing some problems...I started from basic...like linking arduino...
  9. JesseJC

    Matlab Extrapolation: Find Approximate Size of Matrix n∗

    Let A be a random n×n matrix, x = (1,1,...,1)⊤ be an n-vector of ones and b = Ax be the right-hand side vector. As in class, let z = (zj) ∈ Rn be the result of solving the system Ax = b in finite precision using the backslash command. To measure the error between x and z, we let δ= max |xj−zj|...
  10. A

    MATLAB Crank-Nicholson in 2D with MATLAB

    I have the code which solves the Sel'kov reaction-diffusion in MATLAB with a Crank-Nicholson scheme. I would love to modify or write a 2D Crank-Nicolson scheme which solves the equations: ##u_t = D_u(u_{xx}+u_{yy})-u+a*v+u^2*v## ##v_y = D_v(v_{xx}+v_{yy}) +b-av-u^2v## Where ##D_u, D_v## are...
  11. F

    MATLAB Finite difference numerical integration or ode45?

    I'm trying to numerically solve the time dependent Schrödinger equation and I've been told that the best approach is to numerically integrate using a finite difference method, however I don't understand why I couldn't just use ode45 to solve it?! Is the finite difference (interpolation) method...
  12. kelvin490

    MATLAB How to set zero value boxes transparent in 3D plots?

    I used a function called ind2patch to make a big 3D block which contains a number of smaller blocks in 3 dimensions. Each small block has a value which the magnitude is represented by a color.One example is shown below: However, most of the boxes have very low or zero value and I don't need to...
  13. C

    MATLAB Numerical Integration with Matlab - Solve K33, K11 Integral

    Hi all, i need help solving the following integral using Matlab: * tetam is a parameter and the integration is by alpha. the answer should be function of tetam * K33, K11 are constantsThanks , Chen
  14. Nemo's

    Fourier series neither odd nor even

    Homework Statement I'm trying to calculate the Fourier Series for a periodic signal defined as: y = x 0<x<2Π y = 0 2Π≤x<3Π Homework Equations Fn = 1/T ∫T f(t)cos(kwοt + θk)[/B] cn/2 + ∑k=1k=∞(cn)cos(kwοt+θk) cn= 2|Fn| θk=∠Fn The Attempt at a Solution I got Cn =...
  15. H

    MATLAB MATLAB: Plot Contour at 0km Depth

    I'm trying to generate contours that plot with the animation using contour(X,Y) but it's not quite working. I only need it to be in the x-y plane at 0km depth (see picture for greater clarification) % A script to plot two 3D waves. clear %Define the total time for simulation T_total=10; %Set...
  16. E

    Mathematica Numerical vs. Monte-Carlo Simulations

    I have an integration that doesn't have a solution in the table of integrals. So, I evaluated it using Mathematica using the command NIntegrate. However, when I compare the result with Monte-Carlo simulations, there is a very small constant gap between the two curves. Is it because of the...
  17. Molay Mahdi

    MATLAB How to visualize 3D solution on matlab?

    I just want to know how to visulize 3D solution in MATLAB by different ways So please I need some help.
  18. R

    MATLAB Fix Filtering Frequencies Code in Matlab w/o Built-In Filters

    I want to write a Matlab code which removes all frequency components from a .wav sound file except those within ##±25 Hz## of ##523 Hz## as well as its harmonics (up to the Nyquist frequency). I want to do this without using any built in filters. Here is my code so far: [s, Fs] =...
  19. A

    Implementing double series in MATLAB

    Mod note: Moved from a technical forum section, so missing the homework template I want to write code for this double sum in MATLAB and I have written following code: x = 100; % to calculate omega and u l = 300; % to calculate omega p = 10; omegaa= x/l; deltaH = 200; deltat =...
  20. NayKod

    MATLAB Matlab Trial Version: Test Simulation for PhD

    Hello Everybody, I'm new to this interesting forum and this is my first post :) So i wonder if can i use a Trial version of Matlab to perform some simulation for my Phd. Is the Trial version allow doing some important tests ? Thank you for your answer
  21. rolotomassi

    MATLAB Why am I getting a 'Matrix is singular to working precision' error in Matlab?

    Here is a link the code which I am trying to modify. It is the radial average of a matrix function. http://uk.mathworks.com/matlabcentral/fileexchange/46468-radialavg-zip/content/radialavg.m I want to restrict the function to only look within certain angles, e.g. 15 degrees either side of the...
  22. C

    MATLAB How Can I Post Process LabVIEW Signals in MATLAB to Create an Image?

    Hi, I am a novice at MATLAB and just started using it. I need some help with it. I want to post process an array of time domain signals using a specific algorithm. These time domain signals are acquired using labview and I want to post process them using matlab. I have the equation for post...
  23. rolotomassi

    MATLAB How can I smooth pixelated images in MATLAB?

    Hi. I have this code in matlab: / / I=dlmread('C:\Users\rshah\Desktop\Polymer Project\monteCarloCode\E=1e8.txt'); F=fft2(I); F = fftshift(F); % Center FFT F = abs(F); % Get the magnitude since F is complex F = log(F+1); % Use log, for perceptual scaling, and +1 since log(0) is undefined...
  24. S

    Solve question using Excel or Matlab

    water moves over a stationary horizontal flat plate of one-meter length. if velocity of water is 1 m/s, draw boundary layer and friction coefficient versus x for this plate. hint: start your curves from x=1cm.Professor asked us to do it in Matlab or Excel and I'm not sure I understand how to...
  25. R

    Identifying Fundamental Frequencies

    Homework Statement I have made a plot of a given .wav file in Matlab. The problem asks: find the fundamental frequencies of the 3 vibrating strings, and identify some of their harmonics. Homework Equations 3. The Attempt at a Solution [/B] So I made a Matlab plot of the power spectrum over...
  26. DiracPool

    MATLAB How compatible is Freemat with Matlab?

    In post #5 of this thread, Jedishrfu commented that Freemat is a cheap and free alternative to Matlab. My question is how close an alternative is it. I need to learn python and MATLAB for my upcoming entry into a grad program this fall. Python is free, of course, but should I buy the actual...
  27. R

    MATLAB Bisection method and numerical integration

    In Matlab I am trying to use the composite Simpson's rule to find ##x_l## so that $$170=\int^{x_l}_0 \sqrt{1+(y')^2} dx = \int^{x_l}_0 \sqrt{1+\left( \frac{x^2}{68000} \right)^2} dx $$ For convenience this can be written as $$I(x) = 170 - \int^x_0 \sqrt{1 + (\frac{x^2}{68000})} dx$$ The...
  28. Ben Wilson

    MATLAB Replace NaN with next element in Multidimensional Array

    I have a a multidimensional array (49x49x49) which has NaN values scattered randomly. For each NaN, I want to replace the value with the previous non NaN value. e.g. if i had a 3 x 3 matrix 4 7 9 2 7 NaN 1 2 NaN should become 4 7 9 2 7 7 1 2 2 I have 3 dimensions [i,j,k], but...
  29. R

    MATLAB How can I fix the dimensions mismatch in my split-step Fourier method code?

    I am trying to write a very basic Matlab code to preform the split-step Fourier method on the nonlinear Schrodinger equation: $$\frac{\partial A(z,T)}{\partial z} = -i \frac{\beta_2}{2} \frac{\partial^2A}{\partial T^2} + i \gamma |A|^2 A \ \ (1)$$ I want the program to make 3D plots of...
  30. Ben Wilson

    MATLAB Plot 3D Function: Point Where f=1, No Point Where f=0

    I had a function of 3 variables f'(kx,ky,kz) and did an ifft f = ifft(f') and now i have a function where inside a small polygon the function f = 1, and outside f=0, within a cube space of length L. how do i plot a scatter graph for this function where there is a point when f =1, and no...
  31. Ben Wilson

    MATLAB Matlab syntax for 2-d fourier transform

    I have a function f(x,y) which i have defined in this way: a vector x and a vector y meshgrid[x,y] z= f(meshgrid[x,y]). how do i do a 2-d Fourier transform of f(x,y)? the transform must be done without using operations like fft, and must be done using summations written in the code.
  32. Ben Wilson

    MATLAB Fourier transform of a 2D shape

    I have a function of 2 variables [f(x,y)] where if there was an ellipse in the x-y plane, all values of the function are 1 inside the ellipse and 0 outside. I can plot this function as a surface in 3d where it looks like an elevated ellipse hovering over an elliptical hole in a sheet. My...
  33. BubblesAreUs

    How can I model a temperature change using MATLAB?

    Homework Statement Modelling the following equation: k = Delta Q / t Homework Equations Q = T2 - T1 = -40 (fixed) t = Delta Q / k. I need to find t. k can be floating so I suppose 0 to 10 minutes with 0.5 increments The Attempt at a Solution I don't have MATLAB on me at the moment...
  34. R

    MATLAB Create track map using Lateral acceleration & speed in Matlab

    Hi I was wondering if someone could help with creating a track map using lateral accel and speed. More specifically the steps to the maths needed to plot the coordinates. I know how to find the curvature radius but not sure what the next step is. Thanks
  35. DiracPool

    MATLAB Learning Matlab & Python for a DARPA Grant

    I'd appreciate it if someone can give me a little guidance here. I'm slated to be entering a Ph.D. program in the fall where I'll be working on a machine intelligence project under a DARPA grant designed to create autonomous rovers. They want me because of my background in understanding the...
  36. kelvin490

    MATLAB How to use a suitable color bar?

    I have a picture which shows the magnitude of some value in terms of color, like this one: https://www.dropbox.com/s/yoh0n9cqftvrtlz/bar.jpg?dl=0 The higher the magnitude, the more it looks red. However there are only a few points at the edge has very high values and most of the points have...
  37. B

    Blasius Model Solution in Matlab | Boundary Layer Profiles without ODE45

    Homework Statement Program, without any built in functions (like ODE45), a solution to the Blasius Equation in Matlab that outputs boundary layer profiles for given x values, u values, etc. Homework Equations 2f''' + f''f = 0 fj = fj-1 + Δη/2 * (gj + gj-1) gj = [Δη2/4][2gj+1/Δη2 + 2gj-1/Δη2 +...
  38. BubblesAreUs

    Plotting exp(-cx) with MATLAB: Step-by-Step Guide for Homework

    Homework Statement Plotting the exponential exp(-cx), 0 ≤ x ≤ 1 with c = 1, 2, 3, 4. Use a for loop. Homework EquationsThe Attempt at a Solution for c = 1:1:4; for x = 0:1; F = exp(-cx); end end plot(x,F) I'm not really sure where to start.. Help is appreciated.
  39. M

    MATLAB Need help on constants for Matlab nuke sim for uni project

    Hey guys, I am currently working on a uni MATLAB group project for blast radius, thermal radius etc. Apparently these formula are the best possible to use: r_thermal = Y^0.41 * constant_th r_blast = Y^0.33 * constant_bl r_radiation = Y^0.19 * constant_rad But can anybody tell me what...
  40. N

    4th order Runge Kutta Matlab with 2 2nd order ode

    Homework Statement Hi There! MX''=Fn(sin θ - uCos θ ) MZ''=Fn(cos θ + uSin θ ) - Mg Fn,M,θ,u is constant fn/M = 0.866 M = 6000 θ = 30 u = 0.5774 i split my motion equation into 2 individual 1st ode, X' = Vx Z' = Vz Vx'=[fn*(sin θ - uCos θ )]/M Vz'={[fn(cos θ + uSin θ )]/M} - g...
  41. Lucas94

    MATLAB How to do a double integral on matlab?

    Hey! I want to do a double integral calculation of this problem##∫∫ xy/(xy^2 +1)^2## over the region bounded by 2 ≤ x ≤ 3 and 2*sqrt(1+x) ≤ y ≤ 2*sqrt(2+4x) on MATLAB and i have tried the following syntax: clc clear all fun=@(x,y) x*y./((x*y.^2+1).^2); ymax=@(x) 2*sqrt(2+4*x)...
  42. SherLOCKed

    How can I interface a DFIG in a multi machine environment?

    Which will be my reference frame while modelling and control - the reference machine in the network or the network bus itself?And if so how do i relate the dfig to this reference frame?
  43. Lucas94

    Make a circle in square that is split 8x8 parts?

    Sorry if i may sound little unclear, english is not my first langue. I I am looking for a way to create a circle that is in a square cut in 8x8 in matlab. I would be glad if someone could give me a hand. Thanks!
  44. A

    MATLAB New to Matlab, help with vectors

    So like the title says, I'm new to Matlab. I took a programming class on Fortran last year before my college changed the requirement so programming is not new to me all together. For a few of my classes we are allowed to use programs such as Matlab and Maple to help us solve problems. Most of...
  45. Tone L

    MATLAB Solving MATLAB Sum Loop Issue with 2,187 Data Points

    So i want to calculate an r value 5 different times then find the mean of the 5 calculated values. I have 2,187 data points. the first line of code generates 100 random points 1-2187. The code has a bug but my major issue is it calculates r then loops again calculates r, loops again calculates...
  46. S

    MATLAB Center Wavelength of Fiber Bragg Grating Filter

    I would like to locate the center wavelength of a FBG notch filter in MATLAB, but I'm having trouble getting an answer within 0.01nm of the correct wavelength. So far I've tried using a quadratic fit with MATLAB, but that is too dependent on the amount of data points to the left and right of...
  47. S

    Using expm of matlab to plot state responses

    Homework Statement The state space model of a nonlinear system is x'_1(t) = 2x^2_2(t) - 50 x'_2(t) = -x_1(t) - 3x_2(t) + u(t) where x_1(t) and x_2(t) are the states, and u(t) is the input. The output of the system is x_2(t). Find the zero input response (u(t) = 0) of this system linearized at...
  48. A

    How to design an impulse input in Matlab Simulink

    Homework Statement I would like to know a way to design an impulse input in a Matlab Simulink model. I know there are step input and ramp input blocks but there is no impulse input block. Homework Equations The Attempt at a Solution If any working is needed please let me know
  49. A

    Matlab step response. Just need a quick check

    Homework Statement Could someone just quickly check my Step Reponse diagram which I made using Matlab. It does not look like the usual shape for a step response system which is making me a bit worried. I'm a fairly new to Matlab and Control Engineering Homework Equations G(s) = 3 / ((s^2) +3)...
  50. A

    Could someone please check my Simulink Diagram

    Homework Statement I was asked to draw a Simulink Model for the above (car suspension) system. m = 250kg k, spring constant = 70000N/m c, damping coefficient = 3000N/m/s Homework Equations If any equations are needed please let me know The Attempt at a Solution The question says to draw...
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