Community Profile

# Star Strider

##### Last seen: Today
13,286 total contributions since 2012

Hic sunt dracones!

PROFESSIONAL: Physician (M.D.): Diplomate of the American Board of Internal Medicine; M.Sc. Biomedical Engineering: Instrumentation, Signal Processing, Control, System Identification, Parameter Estimation

NON-PROFESSIONAL: Amateur Extra Class Amateur Radio Operator; Private Pilot, Airplane Single Engine Land, Instrument Rating Airplane; Gamer

NOTE: I do not respond to emails or personal messages, unless they are about my File Exchange contributions.

View details...

Contributions in
View by

Obtain single equation from a system of equations stored as an anonymous function
Not directly. I would do this: F = @(x) [x(1).*x(2).^2 + sin(x(2)) ; ... cos(x(1)) + x(2).^3 ] ; z = [2 6];...

2 hours ago | 0

Error using @regress fuction
Try this: func = @(Q)regress(Q,X); then call it as: [b,bint] = func(Change1.ReturnsCleaned); (It seems a bit inefficient...

3 hours ago | 0

MATLAB: solving a 2nd order ODE which has a parameter which evolves in time
Try this: syms k(t) y(t) % Declare ‘k(t)’ Here [System,Subs] = odeToVectorField(...

3 hours ago | 0

| accepted

Overlap of 2 logicals
Since ‘B’ and ‘B2’ have not yeat appeared, try this with synthetic versions of them: B = randi([0 1], 5, 6) > 0 B2 = randi([0...

4 hours ago | 0

| accepted

How to make plot more visible in matlab
See the plot documentation section on Specify Line Width, Marker Size, and Marker Color. That should get you started.

5 hours ago | 0

Solve a second-order differential equation with constant parameters changing through an external parameter
It appears that what you want to do is to pass your data to your ODE function ‘fx’. See the documentation section on Passing Ex...

6 hours ago | 2

| accepted

getting z transform in factored form?using Matlab?
Control System Toolbox: z = tf('z'); H = (4*z^2 + 3*z + 9) / (4*z^2 + 3*z - 4); zsys = zpk(H); Z = [zsys.Z{:}] P = [zsys.P...

7 hours ago | 0

How do I use the "omitnan' option for the Mean function when calling the function using the splitapply function?
One option: splitapply(@(x)mean(x,'omitnan'),MyArray,G)

16 hours ago | 0

| accepted

Print figure without its title
One option is to keep the title in the figure call. See Specify Figure Title for an example. Another option is: title('Ran...

21 hours ago | 0

Error calling a function or indexing a variable, apparently the first line for plotting is wrong, can't figure out whats wrong with it...
The ‘error’ function needs to be defined as an anonymous function, and ‘y’ needs to be the same size as ‘c’. Try this: erro...

22 hours ago | 0

plotting a polinomial fraction over a strict range
I do not have the DSP System Toolbox, so I do not have tfplot. Try this instead: q=[1 1]; d=[1 1 1]; x=0:0.001:3; trf ...

23 hours ago | 0

Finding points with same y-value on a graph.
Try this: x = [2,4,7,9,10,14]; y = [5,10,15,14,12,3]; new_y_value = 12.5 [~,idx] = max(y); newx(1) = interp1(y(1:idx), x(...

24 hours ago | 0

I want to do the correlation of the following two plots
Going back to using my code (because it is easier to work with): Ts=1/200e6; t=Ts:Ts:0.00005; y=[ones(1,2000) zeros(1,8000...

1 day ago | 1

| accepted

system of 3 equation with 3 unknown, with two 2nd order equation
The resuillts are strictly numerical (not containing symbolic variables), so use vpasolve instead of solve: syms QV3 QV2 QVl ...

1 day ago | 0

| accepted

how to solve this complex equation in matlab?
Try this: syms theta gama Eqn = exp(pi/4*i)*(5+15i)+exp(i*theta)*(25+5i) == 40+exp(i*gama)*(-10+20i); [theta,gama] = vpasol...

1 day ago | 0

removing all rows with duplicate information in two columns
Try this: a=[1 2 3 4 5; 1 3 4 5 6; 1 2 3 5 5]; [~,~,idx] = unique(a(:,[1 5]),'rows'); tally = accumarray(idx,(1:numel(idx))....

2 days ago | 0

| accepted

Genetic algorithm plot diagram display
It is generally necessary to write your own code to save specific aspects of the ga output. It may be best to adapt the code ...

2 days ago | 0

How to delete a whole table in the matlab?
tablename = [];

2 days ago | 1

| accepted

How can I separate the arrays when making a table?
Try this: n = 5; A = rand(n,1); B = rand(n,5); T = array2table([A, B]) That should do what you want.

2 days ago | 1

| accepted

how to combine date and time
In theory at least, datetime should be able to do this seamlessly using the timeofday function for the seconds. In practice, it...

2 days ago | 0

What am I doing wrong? Matrix operators
If you want to raaise the elements of a matrix to a power, use element-wise exponentiation with the dot operator: .^ and see: Ar...

2 days ago | 0

I can't plot a function I created with respect for time
You need to code it as an anonymous function. See Anonymous Functions for details. Specifically: x = @(t) X.*(exp(-Zeta.*...

3 days ago | 0

Error when solving system of equations with ode45 in MATLAB R2019b
The system contains only two derivatives, and . It appears that ‘u’ and ‘z’ are either functions that need to be evaluated, or...

3 days ago | 0

How to plot a function that relies on another function?
Since ‘A’ is a function, it must be evaluated in order to use its results. Try this: A = @(y) y*2; X = @(y) A(y)+10; f...

3 days ago | 0

| accepted

How to make this signal linear
If you want to eliminate the low-frequency parabolic(?) trend, the easiest way is to use a digital filter: signal_2 = load('si...

4 days ago | 0

| accepted

Designing IIR Butterworth filter (pass band)
Yes. Just define the order as 5. There are different design functions in the Signal Processing Toolbox (butter that I have a...

5 days ago | 0

Play 2 wav files after each other
Use the playblocking function to get them to play the way you want them. [y1, Fs1] = audioread('file1.wav'); %this file i...

5 days ago | 1

I have a function which is ranged from 0 microseconds to 50 microseconds. I just want to plot its exact copies from 0to50 microsecond,50 to 100microseconds,100 to 150 and so on
Try this: Ts=1/200e6; t=Ts:Ts:0.00005; y=[ones(1,2000) zeros(1,8000)]; x=sin(1256e6*t + 2198e10*t.^2); z=x.^y; NR = ...

5 days ago | 1

| accepted

How to condense a plot with a shorter x-axis?
Divide the x-axis vector by max(x), assuming ‘x’ is the x-axis vector. That will re-scale it without losing any information.

6 days ago | 0

How to avoid a for loop in functions?
Use ‘logical indexing’ and anonymous functions to eliminate the for loop and the if block: PsolWB1 = @(press) (973.-(70400./(1...

6 days ago | 0

| accepted