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HP67 · (This post was last modified: 06-23-2014 07:08 AM by HP67.)

This program seems like it takes much longer than it should to run. How long should it take? I have no idea, but not as long as it is taking. I have another program (not shown) that does some string substitution (replacement) and the seat of the pants feeling is it's faster than it should be. I would have thought that scanning for substrings and replacing them with unlike-sized substrings would be one of the more expensive operations. But this simple piece of code that just concatenates a few strings can't get out of its own way.

As you can see there is not a whole lot going on in this code. 1000 tests of converting 2014 (5 while loop executions) to roman numerals in a loop take 970.3 seconds on a 50g on USB power.

Code:

%%HP: T(3)A(R)F(.);

@

@ ( real or int ==> roman numerals )

@

\<< "" SWAP

  WHILE DUP 0 > REPEAT

     CASE 

        DUP 1000 \>= THEN 1000 "M"  END

        DUP  900 \>= THEN  900 "CM" END

        DUP  500 \>= THEN  500 "D"  END 

        DUP  400 \>= THEN  400 "CD" END 

        DUP  100 \>= THEN  100 "C"  END

        DUP   90 \>= THEN   90 "XC" END

        DUP   50 \>= THEN   50 "L"  END

        DUP   40 \>= THEN   40 "XL" END

        DUP   10 \>= THEN   10 "X"  END

        DUP    9 \>= THEN    9 "IX" END

        DUP    5 \>= THEN    5 "V"  END

        DUP    4 \>= THEN    4 "IV" END

        DUP    1 \>= THEN    1 "I"  END

    END

    ROT ROT -

    ROT ROT +

    SWAP

  END DROP

What is the source of the expression "dog slow?" The dogs I had were anything but slow. And even a slow dog is faster than a man can run.