Gaussian Copula and Correlation, I am trying to find gaussian copula for multiple variable, Please help me, is the u which i underline is correct or not

N = 1000;

norm_mean = 0;

norm_var = 1;

r1= norm_mean+sqrt(norm_var)*randn(1,N);

%calculating PDF

y1 = pdf('Normal',r1,norm_mean,sqrt(norm_var));

%Random variable 2

r2= norm_mean+sqrt(norm_var)*randn(1,N);

y2 = pdf('Normal',r2,norm_mean,sqrt(norm_var));

%Random Variable 3

r3= norm_mean+sqrt(norm_var)*randn(1,N);

y3 = pdf('Normal',r3,norm_mean,sqrt(norm_var));

%Calculate correlation between columns Y1 and Y2

[rho,pval] = corr(y1(:),y2(:),'type','Spearman')

[rho1,pval1] = corr(y2(:),y3(:),'type','Spearman')

[rho2,pval2] = corr(y3(:),y1(:),'type','Spearman')

%Calculating correlation between Y1 and Y2 using corrcoef

[r,p] = corrcoef(y1(:),y2(:))

r2 = copulastat('Gaussian',rho) %check

%calculating Gaussian/Normal copula

u = copularnd('Gaussian',rho,N) +copularnd('Gaussian',rho1,N)+copularnd('Gaussian',rho2,N)

%short the numbers

[s1,i1] = sort(u(:,1));

[s2,i2] = sort(u(:,2));

% two vectors of zeros, x1 and x2, that are the same size as the sorted copula vectors

x1 = zeros(size(s1));

x2 = zeros(size(s2));

x1(i1) = sort(y1);

x2(i2) = sort(y2);

b = [betainv(u(:,1),1,2), betainv(u(:,2),1.5,2)];

figure

scatterhist(b(:,1),b(:,2))

tau_sample = corr(b,'type','Spearman')