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# John

### Naval Surface Warfare Center

21 total contributions since 2011

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Is it possible to copy a figure with transparent background color in MATLAB 7.9 (R2009b)?
I just copied from Matlab (2018a) to Powerpoint 2013, and was able to obtain transparent background by using the set transparent...

1 year ago | 0

How to use lagrange equations for pendulum
Thanks for the clues by John D Errico. There were two errors, the eqn_pend should have a minus sign, and the FF line reversed t...

2 years ago | 0

Question

How to use lagrange equations for pendulum
Below is the code for symbolically simulating a pendulum, the plot produce doesn't seem to be the response of a pendulum swingin...

2 years ago | 1 answer | 0

### 1

How to fit piecewise linear
The problem appears to be by using five unknowns the problem is ill posed. By using 4 unknowns, the calculated line fits the da...

2 years ago | 0

| accepted

Question

How to fit piecewise linear
The code below generates data similar to experimental data. However, the curve fit does not appear to locate the knot point. A...

2 years ago | 1 answer | 0

### 1

Question

How to make a figure of sensor vs azimuth vs rev
In figures 15 to 17 of the attached pdf document the time response of the sensor is plotted vs blade angle and revolution number...

2 years ago | 0 answers | 0

### 0

Question

plot multiple time plots
I want to plot multiple channels of data, all against time, with one channel per plot. Possibly in more than one column if ther...

3 years ago | 1 answer | 0

### 1

Question

Repeat a vector with increment
Given vector a = (1:N)'; with N consecutive integers how to generate matrix b = [a a+1 a+2 ... a+M]; with M columns, each...

3 years ago | 1 answer | 0

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How to simulate a multivariable autoregressive model forecast
With assistance from Matlab support, the following code was created to compare the original data with forecast values from the f...

3 years ago | 0

| accepted

Question

How to simulate a multivariable autoregressive model forecast
Below is the example for arx command, followed by an estimate of the response. How to modify the example and forecast to repres...

3 years ago | 2 answers | 0

### 2

Question

Multi thread C mex for VAR estimation and evaluation
I need a matlab m-file for a simulink matlab function call block. The m-file should consist of two main sub-threads, one for ca...

3 years ago | 0 answers | 0

### 0

Question

How to plot second order ode
syms m c dy k y t y(t) dy(t) y0 dy0 sol=dsolve(m*diff(dy) +c*dy + k*y == 3*sin(2*t),diff(y) == dy,y(0)==y0,dy(0)==dy0); ez...

3 years ago | 0 answers | 0

### 0

Question

How to compare two random signals
I have two simulations of ship motion, and measured ship motion. Generally, the motion is random. I've been asked to compare t...

4 years ago | 3 answers | 0

### 3

Question

Can lagged variables be used in n4sid
A dynamic system is driven by random forcing, so there are only output measurements. AR model works well with a small number of...

4 years ago | 0 answers | 0

### 0

Question

How to color a line based on error range
Original question: I'm trying to color a line based on the error, with levels set at 10% and 25% of the error range. The attach...

4 years ago | 1 answer | 0

### 1

Question

Solve for symbolic initial conditions
A second order mass, damper, spring system can be solved from syms h(t) m c k h0 dh0 C10 C11 Dh=diff(h(t),t); eqs = m...

4 years ago | 1 answer | 0

### 1

Question

How to plot the model prediction error as a function of forecast horizon?
I would like to be able to identify a model from some data, say the first 1000 time samples, and then use the remaining data (80...

5 years ago | 0 answers | 0

### 0

Question

I get the following errors when using mex >> mex -v fmpc_sim.c Verbose mode is on. Neither -compatibleArrayDims nor...

5 years ago | 1 answer | 0

### 1

Help bining 2d data (or using hist2)
Never mind, the error is in the linspace range. Here's the correct code to show 2d hist. function hist3_test close all; cl...

8 years ago | 0

Question

Help bining 2d data (or using hist2)
The following code does not seem to produce the right results. Any suggestions? The upper plot shows the points, while the low...

8 years ago | 1 answer | 0