Function implementation in matlab

I want to implement this function ?[?, ?] = (?^( ?+?)*u[?] using 41*41 array, where u[n] =1 since all the value will be positive ,and n,m from 0 to 40,

N=40
a=0.9
x =zeros(41,41)
for k=0:N
  for col = 1:41
    for row = 1:41
        x(row,col)=a.^(k+k)*1;
    end
  end
end

but id give wrong values

[Suha Ismail]

Anyone can help??

[Suha Ismail]

?

[Walter Roberson]

You are overwriting all of x for each k value.

Hint: n = col - 1

[Suha Ismail]

N=40
M=40
a=0.9
x =zeros(41,41)
for col = 1:41
  for row = 1:41
    for k=0:N
      for i=0:M
        x(row,col)=a.^(k+i)*1;
      end
    end
  end
end

[Suha Ismail]

I chcnage to this code but still not work

[Walter Roberson]

You do not need most of that. You only need two nested loops. Given the row number, you can immediately compute n -- it is just the row number minus 1. Given the column number, you can immediately compute m -- it is just the column number minus 1

for ...
        n = row - 1;
        for ...
            m = col - 1;
            output(row, col) = something involving n and m
        end
end

Answer 1

[Stephen23]

>> a = 0.9;
>> V = 0:40;
>> M = a.^(V+V(:)); % requires >=R2016b

For earlier versions replace the + with bsxfun.