Convert vector loop to matrix loop

There is a loop for working with a vector, can it be made to work with a matrix?

z=zeros(100,900); %
x=z(:,1);
y=x;
j=1;
i=1;
u=1;
c=rand(1,900);
for i=1:100
   j=j+1;
   x(j)=x(i)+0.4*cos(20)/0.226*pi+c(1); 
   % in the c(1) loop this is because the loop is for the first column, 
   % in the matrix loop it should be c(num)
   u=u+1
   y(u)=y(i)+0.64*sin(78)/x(i)*pi+c(1);
end

I will be glad to any advice

[Arif Hoq]

what is value of "a" ? if i choose the variable "a" as a random number, then

a=randi(10,1,100);
z=zeros(100,900); %
x=z(:,1);
y=x;
j=1;
i=1;
u=1;
c=rand(1,900);
for i=1:100
   j=j+1;
   x(j)=x(i)+0.4*cos(20)/0.226*pi+c(1); 
   % in the c(1) loop this is because the loop is for the first column, 
   % in the matrix loop it should be c(num)
   u=u+1;
   y(u)=y(i)+0.64*sin(78)/a(i)*pi+c(1);
end

[Lev Mihailov]

the value of "a" is the value of "x", in future versions of the code, the variable "a" had to be abandoned

[Dyuman Joshi]

Which variable(s) is/are supposed to be a matrix?

[KSSV]

It looks like you need not to use a loop here....tell us your problem, you can vectorize the code striaght away.

Answer 1

[DGM]

You mean like this?

c = rand(1,900);
x = zeros(100,900);
y = x;
for k = 1:99
    x(k+1,:) = x(k,:) + 0.4*cos(20)/0.226*pi + c; 
    y(k+1,:) = y(k,:) + 0.64*sin(78)./x(k,:)*pi + c;
end

... but I should ask how you say it's working when it's clearly dividing by zero and creating an entire array of Infs