code: public static double elementMin( DMatrixSparseCSC A ) {
          if( A.nz_length == 0)
              return 0;
  
          // if every element is assigned a value then the first element can be a minimum.
          // Otherwise zero needs to be considered
          double min = A.isFull() ? A.nz_values[0] : 0;
          for(int i = 0; i < A.nz_length; i++ ) {
              double val = A.nz_values[i];
              if( val < min ) {
                  min = val;
              }
          }
  
          return min;
      }
docs: Returns the value of the element with the minimum value
  @param A (Input) Matrix. Not modified.
  @return scalar