code: public static MatrixFunction asMinusFunction(final double arg) {
          return new MatrixFunction() {
              @Override
              public double evaluate(int i, int j, double value) {
                  return value - arg;
              }
          };
      }
docs: Creates a minus function that subtracts given {@code value} from it's argument.
  
  @param arg a value to be subtracted from function's argument
  
  @return a closure that does {@code _ - _}