This problem series invites you to solve two simple problems related to the integer NUMBER FIVE, in order to celebrate Cody's 5th birthday.

In this problem, let's find the top 5 greatest prime numbers along the first non-singleton dimension of an input array.

Example

• If the input is a vector, the output is a length-5 vector containing the top 5 prime numbers of the input sorted in descending order. Append NaNs as needed in the output if the number of primes is less than 5.

x = 1:10;
y = [7 5 3 2 NaN];

• If the input is a m-by-n (m >= 5) matrix, the output is a 5-by-n matrix containing the column-wise top 5 prime numbers of the input matrix sorted in descending order. Whenever there are less than 5 primes found in a specific column of the input, simply append NaNs as needed in the same column of the output.

% Input x is a matrix
x = [17     6     3
     13     8    17
      1     2     5
      5     3     7
      7    11     2
     31     7     6];

% Output y
y = [31    11    17
     17     7     7
     13     3     5
      7     2     3
      5   NaN     2];

Previous problem in this series: Spot the First Occurrence of 5