A quick precision test
06-07-2014, 04:44 PM (This post was last modified: 06-07-2014 05:59 PM by pito.)
Post: #63
 pito Member Posts: 131 Joined: Jun 2014
RE: A quick precision test
(06-07-2014 12:20 PM)Paul Dale Wrote:  ..
Ahh, the problem seems to be the decimal point limiting the number of significant digits. Adding zeros would increase the number of digits used and hence the correct result.

Expressing the decimal number as a rational yields the result we're looking for:

We make Mr. Wolfram unhappy when not utilizing his recommendations..

We have to explicitly request an N digits precision with any number/constant and calculus (in Mathematica as well in Alfa), otherwise "machine precision" will be used instead.

So for example we want calculate with 666 digits precision:
Code:
 2.989 * sin ( 22.12 / 7.1 - 0.0023 )

It has to be entered into Alfa as:
Code:
 2.989666 * sin ( 22.12666 / 7.1666 - 0.0023666 )

In Mathematica (works in Alfa too]:
Code:
 N[2.989666 * Sin ( 22.12666 / 7.1666 - 0.0023666), 666 ]
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 Messages In This Thread A quick precision test - pito - 06-02-2014, 10:37 PM RE: A quick precison test - Paul Dale - 06-02-2014, 11:04 PM RE: A quick precison test - pito - 06-03-2014, 12:07 AM RE: A quick precison test - Paul Dale - 06-03-2014, 12:13 AM RE: A quick precison test - pito - 06-03-2014, 12:27 AM RE: A quick precison test - Paul Dale - 06-03-2014, 12:36 AM RE: A quick precision test - Claudio L. - 06-04-2014, 01:25 PM RE: A quick precision test - walter b - 06-04-2014, 01:33 PM RE: A quick precision test - Claudio L. - 06-04-2014, 01:42 PM RE: A quick precision test - Paul Dale - 06-04-2014, 09:47 PM RE: A quick precison test - Gerson W. Barbosa - 06-03-2014, 01:51 AM RE: A quick precison test - Massimo Gnerucci - 06-03-2014, 06:21 AM RE: A quick precison test - walter b - 06-03-2014, 11:24 AM RE: A quick precison test - Massimo Gnerucci - 06-03-2014, 11:31 AM RE: A quick precision test - Gerson W. Barbosa - 06-03-2014, 10:20 PM RE: A quick precision test - Didier Lachieze - 06-03-2014, 10:38 PM RE: A quick precision test - Gerson W. Barbosa - 06-04-2014, 05:07 AM RE: A quick precision test - Dieter - 06-04-2014, 01:08 PM RE: A quick precision test - walter b - 06-04-2014, 01:23 PM RE: A quick precison test - HP67 - 06-03-2014, 09:06 AM RE: A quick precison test - Massimo Gnerucci - 06-03-2014, 09:15 AM RE: A quick precision test - everettr - 06-03-2014, 02:11 PM RE: A quick precision test - Gerson W. Barbosa - 06-03-2014, 09:39 PM RE: A quick precision test - Massimo Gnerucci - 06-03-2014, 10:06 PM RE: A quick precision test - Gerson W. Barbosa - 06-08-2014, 02:10 AM RE: A quick precison test - pito - 06-03-2014, 07:23 AM RE: A quick precison test - HP67 - 06-03-2014, 11:50 AM RE: A quick precison test - Paul Dale - 06-03-2014, 12:25 PM RE: A quick precision test - Massimo Gnerucci - 06-03-2014, 12:57 PM RE: A quick precision test - walter b - 06-03-2014, 01:52 PM RE: A quick precision test - Paul Dale - 06-03-2014, 10:10 PM RE: A quick precison test - HP67 - 06-03-2014, 12:41 PM RE: A quick precision test - HP67 - 06-03-2014, 01:01 PM RE: A quick precision test - walter b - 06-03-2014, 01:56 PM RE: A quick precision test - pito - 06-04-2014, 01:38 PM RE: A quick precision test - Claudio L. - 06-04-2014, 02:17 PM RE: A quick precision test - Paul Dale - 06-04-2014, 10:09 PM RE: A quick precision test - Claudio L. - 06-05-2014, 01:18 AM RE: A quick precision test - Paul Dale - 06-05-2014, 02:00 AM RE: A quick precision test - Claudio L. - 06-05-2014, 11:03 AM RE: A quick precision test - Dieter - 06-05-2014, 11:23 AM RE: A quick precision test - Paul Dale - 06-05-2014, 12:06 PM RE: A quick precision test - Claudio L. - 06-05-2014, 09:08 PM RE: A quick precision test - Paul Dale - 06-05-2014, 10:09 PM RE: A quick precision test - Claudio L. - 06-06-2014, 12:57 AM RE: A quick precision test - Claudio L. - 06-06-2014, 01:15 AM RE: A quick precision test - Paul Dale - 06-06-2014, 01:35 AM RE: A quick precision test - pito - 06-06-2014, 11:16 AM RE: A quick precision test - Claudio L. - 06-06-2014, 12:04 PM RE: A quick precision test - Paul Dale - 06-06-2014, 10:55 PM RE: A quick precision test - pito - 06-07-2014, 11:56 AM RE: A quick precision test - Paul Dale - 06-07-2014, 12:20 PM RE: A quick precision test - pito - 06-07-2014 04:44 PM RE: A quick precision test - walter b - 06-08-2014, 05:28 PM RE: A quick precision test - Claudio L. - 06-05-2014, 09:25 PM RE: A quick precision test - Paul Dale - 06-05-2014, 10:20 PM RE: A quick precision test - Claudio L. - 06-06-2014, 01:03 AM RE: A quick precision test - Paul Dale - 06-06-2014, 01:46 AM RE: A quick precision test - pito - 06-04-2014, 02:12 PM RE: A quick precision test - pito - 06-04-2014, 02:31 PM RE: A quick precision test - pito - 06-05-2014, 08:49 PM RE: A quick precision test - walter b - 06-05-2014, 09:07 PM RE: A quick precision test - pito - 06-05-2014, 09:13 PM RE: A quick precision test - Mark Hardman - 06-05-2014, 09:21 PM RE: A quick precision test - pito - 06-06-2014, 12:19 PM RE: A quick precision test - pito - 06-08-2014, 12:44 PM RE: A quick precision test - walter b - 06-08-2014, 01:57 PM RE: A quick precision test - pito - 06-08-2014, 02:07 PM RE: A quick precision test - walter b - 06-08-2014, 03:00 PM RE: A quick precision test - Paul Dale - 06-08-2014, 10:46 PM

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