See if the sudoku is solved.
[solved,code,irow,icol] = sudoku_issolved ( X )
a 9x9 matrix, with 0 for unknown entries
a boolean, %t if the sudoku X is solved
a string. If code="totalsum", then the total of the entries is not 405. If code="subsquare" then a subsquare has a sum different from 45. If code="rowsum", then the sum of entries in a row is not 45. If code="colsum", then the sum of entries in a column is not 45.
an empty matrix, or the integer for the failing row or failing subsquare row.
an empty matrix, or the integer for the failing column or failing subsquare column.
Find out if the solution is found.