Matlab

Nonlinear Curve Fitting Problem
Hello, I need to fit a curve very accurately. The function is n = ( k * sqrt(1 + x^2 / h^2)+phi ) / pi where k, h, phi are fitting parameters and the data is n = 2 3 4 5 6 7 x = 3.7910 4.0640 4.2850 4.4930 4.6750 4.8440 I tried doing a nonlinear least squares, but it comes up a fitted ... 30 May 2010 21:56

rank of the logical matrix A in GF(2)?
How can i calculate the rank of logical Matrix A in a in GF(2)(2) ? In matlab to do it i schould at first use the function A_gf=gf(A,1) to creates a Galois array GF(2) from the matrix A. then i schould calculate the rank from the function A_rank=rank(A_gf) the problem the function rank change the matrix to do... 23 Apr 2010 20:59

how can I generate an ROI polygon given a logical mask?
Hi Matlab users, Does anyone know of a method that will pull out the indices of multiple polygons specified by a mask, for example, say I have a matrix with two polygons: mask = [ 0 1 0 0 0; 0 1 1 0 0; 0 0 0 0 1; 0 0 0 1 1;] The problem is trivial with one polygon, but ... 23 Apr 2010 20:59

invert a large number of matrices
Hi, My first time posting question here. I have an array "A" with size (m X m X n), basically n concatenated square matrices. Is there any faster way to invert each matrix A(:,:,i) instead of using for loop such as: for i=1:n B(:,:,i)=inv(A(:,:,i)); end Thanks! ... 24 Apr 2010 17:14

Speeding up a simple routine.
Hi everyone, I need some ideas on how to speed up some code that appears to be memory bound. I'm only guessing that it is memory bound - the symptoms are odd and I don't really understand them - so maybe someone can first help me understand what I'm seeing.. I say that it appears memory bound because my dual-core ... 26 Apr 2010 08:02

Help with Matlab hw!
Basically: The ideal gas law, Pv = RT, describes the behavior of many gases. When solved for v, the equation can be written v=(RT)/P Find the specific volume for air, for temperatures from 100 to 100K and for pressures 100 kPa to 1000 kPa. The value of R for air is 0.2870kJ/(kg K). In this formulation of the id... 23 Apr 2010 20:59

pdepe solver - Time dependent boundary condition
Hello, I try to impose a boundary condition to resolve a parabolic equation using the pdepe solver. Do you know how to impose a discrete time boundary conition for the right BC like this (series of ramp displacements) : for t<500s, ur = 0.0013*t, 500<t<1000: ur = 0.65, 1000<t<1500: ur = 0.0013*t, 500<t<2000: u... 23 May 2010 19:02

a question about HMM functions in MATLAB
Guys would need help on training and developing an HMM, which needs to be designed to capture an echo signal . based on the types of echoes a most probable vessel which could have emitted it needs to be identified. any help or inputs would be most valuable ... 23 Apr 2010 20:59

Denoising signal / finding knots
Hello everyone, I have some temperature profile data (elevation [Z] in meters, temperature [T] in celcius), sampled every 0.001m. See figure linked below; left plot is an entire profile, right plot is a smaller section of the same profile. http://bit.ly/b0MKPv The fluid this is measured from is quite stratifie... 23 Apr 2010 20:59

data storage
here is my code: *************************** % Omega = 1; k = 100; c = 5; e0 = 5; eR = 8.85 * 10^(-12); h = 0.0015; V = 1; % M = [1:990]; Am = 1; A = 0.10 * 0.06; % for t=1:5000, % x = Am * sin(Omega * t); % xd = diff(x)./diff(t); % end % F = k * x + c * xd + e0 * eR * A * (V^2) / ((h - x)^2);... 23 Apr 2010 20:59