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# Torsten

Last seen: Today Aktiv seit 2013

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Beantwortet
If statement should continue for some values even if "else" is true
You must have a flag which indicates whether the engine is on or off. function [w,T] = EnginePower(B_SoC) persistent on ...

etwa 9 Stunden vor | 0

Beantwortet
Make a loop with a function to vary one value
tspan = [0 :0.01:20]; y0 = 0; opt = odeset('RelTol',1e-12,'AbsTol',1e-16,'MaxStep',0.001); Eta = [10, 50, 100, 500, 1000]; f...

etwa 9 Stunden vor | 0

| akzeptiert

Beantwortet
How i can solve the problem of primitive root?
p = sym('54497'); % p is a prime number a = sym('3'); % a is a primitive root to p istart = 54493; iend = 54496; for i = i...

etwa 9 Stunden vor | 0

Beantwortet
Verify the Divergence theorem in MATLAB
Nice exercise. syms X Y Z x y z syms a phi positive F = [X^2*Y^2,Y^2*Z^2,Z^2*X^2]; divF = diff(F(1),X)+diff(F(2),Y)+diff(F(...

etwa 11 Stunden vor | 0

Beantwortet
How to get the derivate using bvp4c
I assumed Alpha = A in your code. clc; p=0.01; Betaf= 207; Betas = 17; Beta = 0.5; kof = 0.613; kos = 400; m = 1; b2 = ...

etwa 14 Stunden vor | 0

| akzeptiert

Beantwortet
How can I more fully vectorize to eliminate for loops?
Wans2 = (sum(G.*(W.'-V),2)).'

ein Tag vor | 0

| akzeptiert

Beantwortet
Trying to use fsolve works over lower part of range (values < 10) but fails in upper part of range (values > 10)
It's very important that you have a good initial guess for pHv given Vbv. So looping over the complete range of Vbv and taking ...

ein Tag vor | 0

Beantwortet
List of all Binomial permutations with a certain number of events
n = 8; A = dec2bin(0:2^n-1)-'0' A4 = A(sum(A,2) == 4,:) 8*7*6*5/(4*3*2*1) % more general Ai = arrayfun(@(i)A(sum(A,2) == i,...

ein Tag vor | 0

Beantwortet
Code for solving first-order ode with symbolic initial condition
syms y(h) k ode = diff(y) == k*y; sol_ode_general = dsolve(ode) vars = symvar(sol_ode_general) eqn1 = subs(sol_ode_general,v...

ein Tag vor | 0

| akzeptiert

Beantwortet
How to convert PDE into matrix form
Can you write this in matrix form ? m1*diff(x1(t), t, t) + 0*m2*diff(x2(t), t, t) + (c1 + c2) * x1d - c2 * x2d + (k1 + k2) * x...

ein Tag vor | 0

Beantwortet
Why do I receive the error in horzcat?
blkdiag(ddf(x), zeros(n)) is 2x2, A' is 1x1. Thus it's not possible to concatenate the two horizontally in the command H...

ein Tag vor | 0

Beantwortet
Determine the coefficients in symbolic
I don't know why the coefficients appear in the wrong order. syms In In_1 On_1 On = 91/100*In-7/8*In_1+1/2*On_1; coeffs(On,[I...

2 Tage vor | 0

| akzeptiert

Beantwortet
how to solve non-linear equations in a nozzle
Maybe you can give better initial guesses in x0 for the solution than I can ... x0 = 10*rand(7,1); options = optimset('Max...

2 Tage vor | 1

| akzeptiert

Beantwortet
Solving Nonlinear System of Equations with 10 variables
W=100; s=10; S=23; %F=13; %m=9; fun = @(X1,X2,X3,X4,X5,X6,X7,X8,X9,X10)... [5-(W+S*9)*X1+S*9*X2-S*20*X1^2+S*20*X...

2 Tage vor | 0

Beantwortet
calculating Double integral over a region
syms x y int(int(2,y,-sqrt(1-(x/3)^2),sqrt(1-(x/3)^2)),x,-3,3)

3 Tage vor | 1

| akzeptiert

Beantwortet
I am struggling to plot iteration vs error in the matlab code? can anyone help me with this? very much appreciate it.
% Inputs: A - Coefficient matrix A=[2 -1 0;-1 2 -1;0 -1 2]; % b - Input matrix b = [0; 2; 0]; % x0 - Initial guess x0 = [0...

3 Tage vor | 0

| akzeptiert

Beantwortet
Is it possible to get a time-dependent function as an output of an ODE solver?
clear all clc I0= 500; % maximum flow Tc=60/72; % heart period Ts=(2/5*Tc); % time in systole P_ss=80; % diastolic p...

3 Tage vor | 0

Beantwortet
Error in the script
x = -1 : 0.001 : 1; y_div = (x.^2) ./ (1 + (x.^2)); title ('División acotada'); plot (x, y_div);

3 Tage vor | 0

Beantwortet
Reverse problem of finding time-varying parameters of an ODE with the help of solution data.
Use "lsqcurvefit" to fit the parameters together with an integrator (e.g. ODE45). For an example, see Star Strider's code under...

3 Tage vor | 1

Beantwortet
im trying to solve a system of 4 nonlinear equations with 4 unknowns
Equations (1), (3) and (4) give x(2) = 0. Thus it's impossible to satisfy equation (2) where x(2) is in the denominator. syms x...

3 Tage vor | 0

Beantwortet
Corrective action after Newton iteration exception
I wonder if a similar corrrective action happens whenever a Newton-iteration exception occurs: in this case, does the solver sim...

3 Tage vor | 0

| akzeptiert

Beantwortet
The size of X must match the size of Z or the number of columns of Z.
Change dx = 1.01/(Nx-1); dy = 1.01/(Ny-1); to dx = 1.0/(Nx-1); dy = 1.0/(Ny-1);

4 Tage vor | 0

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Beantwortet
Why should I tighten error tolerances if I am violating minimum stepsize?
The stepsize reduction down to the minimum stepsize often occurs because in previous time steps, the solver was not exact enough...

4 Tage vor | 0

Beantwortet
Num2cell question
Most probably too large for your computer: A = rand(12,3,5) A = num2cell(A)

4 Tage vor | 0

Beantwortet
Matlab produces complex number where it cannot be produced
Because (Req.^3-b.*Req.^3)/(R.^3-b.*Req.^3) is negative. If you use k1 = 4; k2 = 1/3; P0=1.00*10^5; Req=69.2*10^(-3); b=...

4 Tage vor | 1

| akzeptiert

Beantwortet
Help with fminsearch to maximise non-analytic function via specific parameters
Here is the optimization solution: theta0 = 10; sol = fminsearch(@fun,theta0) function range = fun(theta) global rho d m g...

4 Tage vor | 0

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Beantwortet
Why are the inputs to the functions used in the ODE45 solver not in the right syntax?
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %This is in thé main script: field = [1,0,1 ; 1,1,1]; %in my script ...

4 Tage vor | 0

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Beantwortet
2nd order differential eqn for Windkessel model
I = @(t) I0*sin((pi*t)/Ts).^2.*(t<=Ts); %input current flow Idot = @(t) I0*2*sin(pi*t/Ts).*cos(pi*t/Ts)*pi/Ts.*(t<=Ts); Idotdo...

4 Tage vor | 0

| akzeptiert

Beantwortet
Help with fminsearch to maximise non-analytic function via specific parameters
Of course, you could use fminsearch for optimization. But using it, you will only get a single point of the below graph. Theta ...

4 Tage vor | 0

Beantwortet
What type of solver is VPA Solve?