Re: PL/I Integer arithmetic (was: Constant Identifiers)
Since when is 1.33... an integer? -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 From: IBM Mainframe Discussion List on behalf of Robin Vowels Sent: Wednesday, September 9, 2020 10:08 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: PL/I Integer arithmetic (was: Constant Identifiers) From: "Seymour J Metz" Sent: Monday, September 07, 2020 4:13 PM > PL/I has never had integers. It always has had integers. > The arithmetic rules for scaled fixed point are different from those for > integers. > In integer arithmetic, (4/3)*6 is 6 That's not the result you get in PL/I. Yes it is, with declarations as shown, as I said before, . Under IBM rules: %PROCESS RULES(IBM); INTEGER_DIVISION: PROCEDURE OPTIONS (MAIN); DECLARE (A, B) FIXED DECIMAL (15); A = 4; B = 3; PUT (4/3); PUT (A/B); PUT ( (A/B) * 6 ); END INTEGER_DIVISION; /* RESULTS: 1.33 1 6 */ And under Rules (ans): %PROCESS RULES(ANS); INTEGER_DIVISION: PROCEDURE OPTIONS (MAIN); DECLARE (A, B) FIXED DECIMAL (15); A = 4; B = 3; PUT (4/3); PUT (A/B); PUT ( (A/B) * 6 ); END INTEGER_DIVISION; /* RESULTS: 1.33 1 6 */ As you can see, the results are the same under IBM and ANS rules. From: IBM Mainframe Discussion List on behalf of Robin Vowels Sent: Sunday, September 6, 2020 7:06 PM Subject: Re: Constant Identifiers - Original Message - From: "Seymour J Metz" Sent: Monday, September 07, 2020 5:33 AM > PL/I doesn't have integers. PL/I has always had integers. > The ratiio 4/3 is FIXED BIN, No it not. It is FIXED DECIMAL -- as I said a few days ago. And it hasn't changed since. > with some number of bits after the binary point. DECIMAL digits after the decimal point, because the reault is FIXED DECIMAL, not binary. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: PL/I Integer arithmetic. (was: Constant Identifiers)
The results that you have described are not integer arithmetic. In integer arithmetic, 4/3 is 1. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 From: IBM Mainframe Discussion List on behalf of Robin Vowels Sent: Wednesday, September 9, 2020 10:14 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: PL/I Integer arithmetic. (was: Constant Identifiers) - Original Message - From: "Seymour J Metz" Sent: Monday, September 07, 2020 3:02 PM Subject: Re: Constant Identifiers 4/3 yields 1.3, 04/3 yields 1332, ... Rubbish. 4/3 yields 1.33 INTEGER_DIVISION: PROCEDURE OPTIONS (MAIN); DECLARE (A, B) FIXED DECIMAL (15); A = 4; B = 3; PUT (4/3); PUT (A/B); PUT ( (A/B) * 6 ); END INTEGER_DIVISION; /* RESULTS: 1.33 1 6 */ However, DIVIDE(4,3,16,15) yields 1.3...2 to 15 digits No, it yields 1.33 From: IBM Mainframe Discussion List on behalf of Robin Vowels Sent: Sunday, September 6, 2020 7:58 PM Subject: Re: Constant Identifiers From: "Paul Gilmartin" <000433f07816-dmarc-requ...@listserv.ua.edu> Sent: Sunday, September 06, 2020 1:33 PM On Sat, 5 Sep 2020 08:13:42 +1000, Robin Vowels wrote: > >As for writing formulas, I prefer to follow a well-known formula, thus: > >volume = 4/3 * 3.14159 * radius**3 > Beware! Than might left-associate as: volume = ( 4/3 ) * 3.14159 * radius**3 "might"? Evaluation MUST proceed left to right. So, whether it is written as 4/3 or (4/3), the division will be done first. > ... and the quotient of integers, 4/3, is 1. As I indicaed before, 4/3 yields 1.333.to 15 digits. >However, if I'm interested in efficiency, I'd prefer > >volume = 4 * 3.14159E0 / 3 * radius**3 > ... (and correct.) Yes, it's correct, but I wrote it that way in order to avoid unnecessary conversions and arithmetic in fixed-point. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: PL/I Integer arithmetic. (was: Constant Identifiers)
- Original Message - From: "Seymour J Metz" Sent: Monday, September 07, 2020 3:02 PM Subject: Re: Constant Identifiers 4/3 yields 1.3, 04/3 yields 1332, ... Rubbish. 4/3 yields 1.33 INTEGER_DIVISION: PROCEDURE OPTIONS (MAIN); DECLARE (A, B) FIXED DECIMAL (15); A = 4; B = 3; PUT (4/3); PUT (A/B); PUT ( (A/B) * 6 ); END INTEGER_DIVISION; /* RESULTS: 1.33 1 6 */ However, DIVIDE(4,3,16,15) yields 1.3...2 to 15 digits No, it yields 1.33 From: IBM Mainframe Discussion List on behalf of Robin Vowels Sent: Sunday, September 6, 2020 7:58 PM Subject: Re: Constant Identifiers From: "Paul Gilmartin" <000433f07816-dmarc-requ...@listserv.ua.edu> Sent: Sunday, September 06, 2020 1:33 PM On Sat, 5 Sep 2020 08:13:42 +1000, Robin Vowels wrote: As for writing formulas, I prefer to follow a well-known formula, thus: volume = 4/3 * 3.14159 * radius**3 Beware! Than might left-associate as: volume = ( 4/3 ) * 3.14159 * radius**3 "might"? Evaluation MUST proceed left to right. So, whether it is written as 4/3 or (4/3), the division will be done first. ... and the quotient of integers, 4/3, is 1. As I indicaed before, 4/3 yields 1.333.to 15 digits. However, if I'm interested in efficiency, I'd prefer volume = 4 * 3.14159E0 / 3 * radius**3 ... (and correct.) Yes, it's correct, but I wrote it that way in order to avoid unnecessary conversions and arithmetic in fixed-point. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: PL/I Integer arithmetic (was: Constant Identifiers)
From: "Seymour J Metz" Sent: Monday, September 07, 2020 4:13 PM PL/I has never had integers. It always has had integers. The arithmetic rules for scaled fixed point are different from those for integers. In integer arithmetic, (4/3)*6 is 6 That's not the result you get in PL/I. Yes it is, with declarations as shown, as I said before, . Under IBM rules: %PROCESS RULES(IBM); INTEGER_DIVISION: PROCEDURE OPTIONS (MAIN); DECLARE (A, B) FIXED DECIMAL (15); A = 4; B = 3; PUT (4/3); PUT (A/B); PUT ( (A/B) * 6 ); END INTEGER_DIVISION; /* RESULTS: 1.33 1 6 */ And under Rules (ans): %PROCESS RULES(ANS); INTEGER_DIVISION: PROCEDURE OPTIONS (MAIN); DECLARE (A, B) FIXED DECIMAL (15); A = 4; B = 3; PUT (4/3); PUT (A/B); PUT ( (A/B) * 6 ); END INTEGER_DIVISION; /* RESULTS: 1.33 1 6 */ As you can see, the results are the same under IBM and ANS rules. From: IBM Mainframe Discussion List on behalf of Robin Vowels Sent: Sunday, September 6, 2020 7:06 PM Subject: Re: Constant Identifiers - Original Message - From: "Seymour J Metz" Sent: Monday, September 07, 2020 5:33 AM PL/I doesn't have integers. PL/I has always had integers. The ratiio 4/3 is FIXED BIN, No it not. It is FIXED DECIMAL -- as I said a few days ago. And it hasn't changed since. with some number of bits after the binary point. DECIMAL digits after the decimal point, because the reault is FIXED DECIMAL, not binary. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
