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User RPL Question - Paul Berger (Canada) - 10-21-2011
While playing with user RPL I have noticed that on 49G and later calculators my program that contains some nested loops performs much better if I put a decimal point after constants. On the 49G more than 4 times improvement in run time. I searched through the AUR but did not find any mention of what this does. Could someone point me to some information on what the decimal point does?
Re: User RPL Question - Cristian Arezzini - 10-21-2011
The HP49 and 50g have two different kinds of numbers: integers and reals. For example, "5." is a real and "5" is an integer. There are different internal algorithms depending on which one you use, and the difference in execution time can be really large, as you noticed! I had to modify all my old 48G programs, to add the "." after numbers...
Cristian
Re: User RPL Question - Crawl - 10-21-2011
Actually, if you open (for modifying) a program in approximate mode and save it, decimals will AUTOMATICALLY be added after every number.
Personally, I don't like that feature, as there is no (as far as I know) similar feature to remove all the decimals, and there have been times I accidentally added them and then needed to remove them manually.
Re: User RPL Question - Eddie W. Shore - 10-21-2011
Quote:
Actually, if you open (for modifying) a program in approximate mode and save it, decimals will AUTOMATICALLY be added after every number.Personally, I don't like that feature, as there is no (as far as I know) similar feature to remove all the decimals, and there have been times I accidentally added them and then needed to remove them manually.
I ran into that situation myself - once the program adds automatic decimal points, there is no way back.
Re: User RPL Question - Eddie W. Shore - 10-21-2011
Quote:
The HP49 and 50g have two different kinds of numbers: integers and reals. For example, "5." is a real and "5" is an integer. There are different internal algorithms depending on which one you use, and the difference in execution time can be really large, as you noticed! I had to modify all my old 48G programs, to add the "." after numbers...Cristian
Would you recommend that programs be entered and ran in Approx mode and if exact numbers/expressions are necessary just take a XQ or -> Q command at the end?
I just noticed that running ->Q switches the calculator from Approximate mode to Exact mode
Edited: 21 Oct 2011, 3:27 p.m.