Community Profile

photo

Stephan


Last seen: Today
1 320 total contributions since 2017

Knowledge means knowing where it is written...

Interested in:
- Optimization
- Mathematical Modelling
- Improvement of my programming skills

Contact

Stephan's Badges

  • 24 Month Streak
  • Personal Best Downloads Level 1
  • First Review
  • First Submission
  • Guiding Light
  • Introduction to MATLAB Master
  • Thankful Level 2
  • Knowledgeable Level 4
  • Revival Level 3
  • Speed Demon
  • Creator
  • First Answer
  • Commenter
  • Promoter
  • Solver

View details...

Contributions in
View by

Answered
Removing specific rows from a matrix where its corresponding element in another column is zero.
ans = abc; ans(abc(:,3)==0,:) = []

ungefär 3 timmar ago | 0

Answered
plot surface using different x,y vector increment and got different graph
You did not multiply elementwise, also you can shorten your code a little bit: fun = @(x,y) -1.448-0.477*x-0.4757*y+0.1473*x.^2...

ungefär 4 timmar ago | 0

Answered
Is the graph correct for the distance 10km for the okumura model?
There is a publication at FEX which you could use to check your code: https://de.mathworks.com/matlabcentral/fileexchange/28423...

ungefär 4 timmar ago | 0

Answered
how to plot a function symbolically?
g = 9.8; r = -10:0.1:10; H = -10:0.1:10; C = -10:0.1:10; fun = @(r,H,C) H - C.^2./(2*g*r.^2); z_r = fun(r,1,1); z_H = ...

ungefär 4 timmar ago | 0

Answered
why when i plot the graph for the okumura model it doesnt show line?
f is a scalar here - for this reason you have only one data point. Either use scatter to visualize the point or make f an array ...

ungefär 5 timmar ago | 0

| accepted

Answered
Unable to convert the text to datetime using the format: 'dd-MM-yyyy hh:mm'
datetime('22-9-2020 10:35','InputFormat','dd-MM-yy HH:mm') datetime('22-9-2020 15:48','InputFormat','dd-MM-yy HH:mm') ans = ...

ungefär 23 timmar ago | 0

| accepted

Answered
How do I plot given points using a functions?
x = [1,12,2,6,5] y = [5,23,5,6,3] plot(x,y) % Using a function handle y_fun = @(x) 3.*x + 5; y_vals = y_fun(x); plot(x, ...

en dag ago | 0

Answered
Solve the equation for x
Make the changes suggested in the answer from KSSV and use vpasolve: syms x p = 0.89; a = 6.7; v = 26.12; r = 0.07; L = 78...

en dag ago | 1

Answered
How can I solve this two shaded equations for d1 and d2?
syms d1 d2 Grin eq = [d2 == Grin * d1; (d1+d2) / 2 == 0.15]; sol = solve(eq,[d1,d2]); sol_d1 = sol.d1 sol_d2 = sol.d2

en dag ago | 0

Answered
Alzheimer detection from brain mri image
Have a look at FEX: https://de.mathworks.com/matlabcentral/fileexchange/55107-brain-mri-tumor-detection-and-classification htt...

en dag ago | 0

Answered
how to plot three figures in single figure?
r=[12 23 45 67 77] p=[44 55 66 77 88 ] g=[21 33 23 34 54] k=[55 45 43 23 12] figure plot(r) hold on plot(p) plot(g) plo...

en dag ago | 1

| accepted

Answered
Errors using ode45
%Define PMOIs Ix = 2887; %kg-m^2 Iy = 2887; %kg-m^2 Iz = 5106; %km-m^2 %Define initial conditions x1_0 = 0.6; % OmegaX ...

en dag ago | 0

| accepted

Answered
GA does not solve problems with integer and equality constraints.
Reformulate your constraints: <https://de.mathworks.com/help/gads/mixed-integer-optimization.html#bs1clc2>

en dag ago | 0

| accepted

Answered
Error using sym/subsindex () while using the symsum function
There are two possible ways in Matlab, that allow a syntax like V(k) The first is indexing with a variable like in a for loop:...

en dag ago | 0

Answered
Convert cartesian coordinates to polar coordinates
Edit your file - you did not declare it as a function, so Matlab uses it as a script. Also think about to vectorize your code, t...

2 dagar ago | 2

| accepted

Answered
Creating a symbolic array
>> q = sym('q', [5, 5]) q = [ q1_1, q1_2, q1_3, q1_4, q1_5] [ q2_1, q2_2, q2_3, q2_4, q2_5] [ q3_1, q3_2, q3_3, q3_4...

2 dagar ago | 0

Answered
I'm getting an error "Undefined function 'Romberg' for input arguments of type 'char'." I'm trying to code the romberg integration method.
For me it worked: a = 0; b = pi; nmax = 3; fun ='sin (x)' ; [t, r]= Romberg (fun, a, b, nmax) function[t , r] = Romberg...

2 dagar ago | 0

Answered
Is it possible to solve the equation for x?
syms x a(1) = 0.89; a(2) = 6.7; a(3) = 26.12; a(4) = 0.07; a(5) = 78.05; a(6) = 34.01; a(7) = 0.33; a(8) = 22.49; a(9) ...

2 dagar ago | 0

Answered
Fill a vector with two vectors
V1 = [3 8 6 7] V2 = [1 5 9 4] V = reshape([V1;V2],1,[]) V = V(3:end) results in: V1 = 3 8 6 7 V2 =...

2 dagar ago | 1

Answered
Trying to plot this curve what have I done wrong?
fun = @(x)(18*sqrt(2)*(sqrt(1+1./(1+x.^2)) + asin(1./(1+x.^2)-pi/2))) fplot(fun)

2 dagar ago | 0

Answered
How to find the solution of inverse function ?
x = [1 2 3 4 5 6 7]; y = [3.6 1.8 1.2 0.9 0.72 1.5 0.51429]; p = polyfit(x,y,2) syms x fx(x) = poly2sym(p) gx(x) = finvers...

2 dagar ago | 0

| accepted

Answered
Possible combinations for a vector
You could use allcomb from FEX: k = 0:2; coms = allcomb(k,k,k,k,k,k,k,k,k); as expected there are 3^9 = 19683 results

2 dagar ago | 1

| accepted

Answered
how do i write a matlab script to sum this expression?
Symbolic: syms n positive integer N = 10000; eq = 1/n + 1/((n+2)*(n+3)); pretty(eq) sol = symsum(eq,n,1,N) sol_num = doubl...

2 dagar ago | 1

Answered
ODE Function time output
Use events: Z0 = 6; Zt=0.05*6; tspan = [0 24]; opts = odeset('Events',@(tZ,Z)EventsFcn(tZ,Z,Zt)); [tZ,Z,tZe,Ze,iZe] = ode45...

3 dagar ago | 0

| accepted

Answered
Why isn't my code graph anything.
Try: %create a cater plot clear all; %x = [20,30,40,50] x = [-3,-1,1,2] y = [8,23,28,34] y=[8,23,28,34].' colum = [...

3 dagar ago | 0

Answered
How find symbolic solution matlab
It appears that there either is no symbolic solution or Matlab is not powerful enough to find one. For sin(t) it would work. How...

3 dagar ago | 1

Answered
ode 45 and for loop
k = 0; T_sol = cell(1,100); X_sol = cell(1,100); for ii = 0.1:0.1:10 k = k+1; [T,X] = ode45(@(t,x)fx(t,x,ii), [0 ...

3 dagar ago | 0

| accepted

Answered
Graph Plotting the differential equation
yyaxis left fplot(qSol,[0, 100]) yyaxis right fplot(TSol,[0, 100])

3 dagar ago | 1

| accepted

Answered
Defining function file of ODE function
C0 = 5; tspan = [0 10]; [t,C] = ode45(@Conc,tspan,C0); plot(t,C) function dCdt=Conc(t,C) k1=0.7; Vo=1; Q=Vo; Cin=200; ...

3 dagar ago | 1

| accepted

Answered
How do i plot this quadratic graph?
x = -10:10; y = polyval([1 -2 -4],x); plot(x,y) r = roots([1 -2 -4]) text(r(1),0,'\leftarrow Root') text(r(2),0,'\leftarrow...

3 dagar ago | 0

Load more