Matlab

Finite difference of Boussinesq equation for waterr table dynamics
Hello everyone, I am trying to solve one and two dimensional Boussinesq equations for groundwater dynamics using implicit finite difference method. I am new to MATLAB and programming so any help to my problem is highly appreciated. Below is the the equation I am trying to solve. dy/dt = a*d/dx(ydy/dx) + a*d/dz(ydy... 3 May 2010 16:27

How to get R square
I am trying to get linear regression of 10,000 sets of data by using polyfit. Anyone call tell me how to estimate the R square (or R^2)? Thank you. ... 3 May 2010 16:27

change seen resolution of defined ticks
Hi, I use the 'datestick' function to define dates for my data. This is a daily data set of 9 years. When plotted, I can only see the dates when zooming in, but when looking at the whole graph the dates cannot be seen (black bar due to many ticks). But if I use a running number for each day (i.e. 1-2992), Matlab know... 3 May 2010 15:21

what does simulink invalid des pointer error mean?
I am using a Simulink (with SimEvents) model that was built in R2010. The model runs fine in this version. I save the file as a R2009b version. When I attempt to run the file, I get an error message with the following information: Message Source ReportedBy Summary Model error Unknown Si... 3 May 2010 15:21

how to take off scale in a figure?
Hi all, As we known, the scale in a figure will be shown as | ... | ... | ... | ... | ... | How to turn off the display of scale "| ... | ... | ... | ... | ... |"? Thanks ... 3 May 2010 16:27

Running shell commands...
I am getting the message: 'MANPATH: Undefined variable' when I run a shell command within Matlab such as 'ls'. What does this mean and how can I correct this? I am running Matlab in Mac OS-X. Thanks, S ... 3 May 2010 17:36

finding maximum in matrix/image
I want to find the indicies of the maximum value in an image/matrix c and do it like this: [d,i] = max(c); [e,j] = max(d); col = i(j); row = j; This seems like a lot of code for a simple task. How could this be achieved with more condensed (prettier) code? Magnus ... 3 May 2010 16:27

Cross correlation to find time lag by employing chirp signal
My task seems to be simple yet I am unable to figure what the hell is going wrong in my code! My problem involves inputing the audio signal recorded by 2 mics to the MATLAB code and finding the time lag between them. But before going to experiment I wanted to check my code by performing a simulation. For this, I gener... 3 May 2010 15:21

Plotting Functions - Logarithmic Decrement
Hi I would like to plot the logarithmic decrement of a structures transient vibration response signal so I can calculate its damping ratio. I can do it manual by simply looking through the data to identify the positive or negative amplitude peaks of the signal. However I have been unable to create an automated m-... 3 May 2010 14:14

lsqcurvefit, jacobian
Hello, I wonder why there is now option for calculating the jacobian matrix in parallel mode (UseAlways == true) in the lsqcurvefit algorithm. Is there reason any plausible reason, why there is no option for it? Best regards, Michael ... 4 May 2010 12:19