Compare the entire elements of matrix with a number

Hi everyone, please guide me, I wanna to build a function that compares every elements in a matrix say A with a-number say H for example; For n=1:1000 e=0.005; H= (n-1)*e; A=[1 2 3; 3 4 5; 7 10 15]; If A>=H Bounce = 0 else Bounce = 1 end end

[madhan ravi]

result ??? How should it look like for the example above?

Answer 1

[Sulaymon Eshkabilov]

Hi,

Here is the one of the possible solutions:

e=0.005;
n=1:1000;  
H=(n-1)*e; 
A=[1 2 3; 3 4 5; 7 10 15]; 
for ii=1:1000;
    if A>=H(ii)
        Bounce =0
    else
        Bounce=1
    end
end

[anas khalaf]

Thank you so much for your replay, actually im working on the geometric Brownian motion, i bulid my code but it doesnt work as i want, i changed it acording to your comment but try it also not working correctly!!!! the two processes shouldnt cross each other, when the are about to meet should bounce away from each other. thats what i want to do, what i have to do .. thanks in advance, this is my code below

randn('state',100)
mu = -2; mu2 = 2; sigma=1; sigma2=1; Xzero = 50; Yzero = 10;   Delta = 0.005; 
p = 10; N = 2^p; T = 1; dt = 1/N; n=1:1000; 
dW = sqrt(dt)*randn(1,N); % Brownian increments
W = cumsum(dW);           % discretized Brownian path
Alpha = mu*([dt:dt:T])+sigma*W;
Betta = mu2*([dt:dt:T])+sigma2*W;
A = log(Xzero)+ Alpha; B = log(Yzero)+ Betta; 
H=(-2*(n-1)*Delta);
D = (A-B); L = sum((n-1)*Delta);
for ii=1:1000;
    if D>=H(ii)
        Bounce =0
    else
        Bounce=L
    end
end
X = Xzero*(exp(Alpha+Bounce));
plot([0:dt:T],[Xzero,X],'b-'); hold on
% % %  % 
Y = Yzero*(exp(Betta-Bounce)); 
plot([0:dt:T],[Yzero,Y],'r-'); hold off

[anas khalaf]

[madhan ravi]

Sulaymon Eshkabilov's answers moved here for consistency:

There are some issues in your initial given data that need to be fixed. (1) Your set initial values of Xzero and Yzero are meant to make the computed values of X and Y to cross each other. (2) L is very large value and thus, X will go to inf when D<H(ii). Thus, L has to be adjusted. (3) The range of "n" has to be selected accordingly.

When you fix these two issues, this code should work:

clear variables
randn('state', 100)
mu = -2; mu2 = 2; sigma=1; sigma2=1; 
Xzero = 50; Yzero = 10;   
Delta = 0.005; 
p = 10; N = 2^p; T = 1; dt = 1/N; n=1:1000; 
dW = sqrt(dt)*randn(1,N);  % Brownian increments
W = cumsum(dW);               % discretized Brownian path
Alpha = mu*([dt:dt:T])+sigma*W;
Betta = mu2*([dt:dt:T])+sigma2*W;
A = log(Xzero)+ Alpha; B = log(Yzero)+ Betta; 
H=(-2*(n-1)*Delta);
D = (A-B); L = sum((n-1)*Delta);
X=zeros(size(n)); Y=X;
for ii=n;
    if D>=H(ii)
        Bounce =0;
    else
        Bounce=L;
    end
    X(ii) = Xzero*(exp(Alpha(ii)+Bounce));
    Y(ii) = Yzero*(exp(Betta(ii)-Bounce)); 
end

Good luck

Note that the size of "n" has to match with the size of 0:dt:T, if not then the plot function will produce the error that you encountered already. Or vice-versa, the size of dt has to be selected with respect to n.

[anas khalaf]

Thank you so much dear Sir

I already did that, with all these edits the same Propblem still arising, the processes still cross each other the Bouncing doesint work on the whole interval !!!!

clear variables
randn('state', 100)
mu = -2; mu2 = 2; sigma=1; sigma2=1; 
Xzero = 50; Yzero =10;   
Delta = 0.005; 
p = 10; N = 2^p; T = 1; dt = 1/N; n=1:N; 
% rnd = randn(1,N);
dW = sqrt(dt)*randn(1,N);     % Brownian increments
% dW = sqrt(dt)*rnd;     % Brownian increments
W = cumsum(dW);               % discretized Brownian path
Alpha = mu*([dt:dt:T])+sigma*W;
M = 2^p; S = 1; ds = 1/M;
dW2 = sqrt(ds)*randn(1,M);    % Brownian increments2
% dW2 = sqrt(ds)*rnd;    % Brownian increments2
W2 = cumsum(dW2); 
Betta = mu2*([ds:ds:S])+sigma2*W2;
A = log(Xzero)+ Alpha; B = log(Yzero)+ Betta; 
H=(-2*(n-1)*Delta);
D = (A-B); L =(n-1)*Delta;
X=zeros(size(n)); Y=X;
for ii=n
%     L(ii) =sum(n-1)*Delta;
%L(ii) =(ii-1)*Delta;
    if D(ii)>=H(ii)
        Bounce =0;
    else
        Bounce=L(ii);
    end
    X(ii) = Xzero*(exp(Alpha(ii)+Bounce));
    Y(ii) = Yzero*(exp(Betta(ii)-Bounce)); 
end
plot([0:dt:T],[Xzero,X],'b-'); hold on 
plot([0:ds:S],[Yzero,Y],'r-'); hold off
xlabel('Time')
ylabel('position')