Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hJvF0-0000rJ-ER for pgsql-sql@arkaria.postgresql.org; Fri, 26 Apr 2019 07:25:50 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1hJvDz-000132-KS for pgsql-sql@arkaria.postgresql.org; Fri, 26 Apr 2019 07:24:47 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hJlbf-0005jd-Cq for pgsql-sql@lists.postgresql.org; Thu, 25 Apr 2019 21:08:35 +0000 Received: from mail-lj1-x243.google.com ([2a00:1450:4864:20::243]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hJlbc-0002NN-P6 for pgsql-sql@lists.postgresql.org; Thu, 25 Apr 2019 21:08:35 +0000 Received: by mail-lj1-x243.google.com with SMTP id q66so929513ljq.7 for ; Thu, 25 Apr 2019 14:08:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:message-id:mime-version:subject:date:in-reply-to:cc:to :references; bh=y30QT9doYdKFInkMNG7fZyQJTN7gcJE9k4nBJkrbJU0=; b=NJewiyv8AyYuLjJdQzhHkvfUnDsd4q80sZWCRSq6lceWWtGPfvZtdFJCuGuM8V4AC/ 5jKVxJvzR9N5cPBRVBM/LVtjGn9hVUCXayGO2afbt67AV/9Bksuv5XKA1o0GKG6gT+rJ cqFJUiaenP8EZm9mgzAQxvdHTM8luKzJyH+voGQI5Mwo1clCeGAi0yj2vIm1oA203VoV lhDhLiwHmnnESp/b6TdZa53G+E/g5UEb8HV0yUdW8vRlPXdtDxALfIG5KGuzp41JZ6Y1 9tLptTA1Ba0c/VvEZYPr12OqKC/X8CHHTRsj8OAnOW1I4mz+U9LANJbmuNlHfQwjgM9i 6Hnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:message-id:mime-version:subject:date :in-reply-to:cc:to:references; bh=y30QT9doYdKFInkMNG7fZyQJTN7gcJE9k4nBJkrbJU0=; b=APV952tB6N/CK5Ql/qLt+GxlMIdfHiaRnictn2L7H1+NnZqDJ9DElXM3S46gCkXbFU hjZJLzIdktZ4HjgA+cJnksl+OEGq3IXYz2kAMaXX65Af1fnOLEIxJai/WOW4IcXr8vjz 50A6vxqBKzfG+TCNIkJAH0qIFwRY5m6jRGap9MvdTnfXK7sZUK4+/iN3GMDYvPpxX4G6 qt1HIfLa1F6fQUt+x0ecCVGRsEmpW1Bev0bgfze2+5OKI1qJC94v/dX5luvO4v1rfott qP5vCpSQ2mhH18X7ygui4MEuICAiILMPNAevVpMs0k10Jo4BtRayPOFNvpjTmOjzWX38 tuMQ== X-Gm-Message-State: APjAAAUR6ZgLVHCOrI76QavWpbwvOTmLEcZeIoHwgOPaPY92ynANLu2O KkvaEzvitrj5AmeQNUZ9RRs= X-Google-Smtp-Source: APXvYqwrr2yZB9RXmavhiPEwLKpF7QZszCkw2yA0As5QH6IrEbEWJvyihFP0SRFFXTxFv5du6IJhMg== X-Received: by 2002:a2e:9a0f:: with SMTP id o15mr12453873lji.130.1556226511779; Thu, 25 Apr 2019 14:08:31 -0700 (PDT) Received: from [10.8.2.22] ([165.231.142.14]) by smtp.gmail.com with ESMTPSA id m24sm1174419ljb.67.2019.04.25.14.08.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 Apr 2019 14:08:30 -0700 (PDT) From: Max Lipsky Message-Id: <32A34C31-946E-4946-8CD1-DB36F70160ED@gmail.com> Content-Type: multipart/alternative; boundary="Apple-Mail=_32B80C0F-EF6C-43B9-897F-047D64FEF61C" Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.8\)) Subject: Re: Problem in Date: Fri, 26 Apr 2019 00:08:27 +0300 In-Reply-To: <26108.1556211406@sss.pgh.pa.us> Cc: pgsql-sql@lists.postgresql.org To: Tom Lane References: <2164C531-EAA3-4CAF-996F-FEB0E5F73B32@gmail.com> <26108.1556211406@sss.pgh.pa.us> X-Mailer: Apple Mail (2.3445.104.8) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk --Apple-Mail=_32B80C0F-EF6C-43B9-897F-047D64FEF61C Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Hello Tom! I think is too much for roundoff error Found funny post about it: = https://randomascii.wordpress.com/2014/10/09/intel-underestimates-error-bo= unds-by-1-3-quintillion/ = http://notabs.org/fpuaccuracy/index.htm = > On 25 Apr 2019, at 19:56, Tom Lane wrote: >=20 > Max Lipsky writes: >> SELECT acos( >> cos(radians(48.9193)) >> * cos(radians(48.9193)) >> * cos(radians(2.5431) - radians(2.5431)) >> + sin(radians(48.9193)) >> * sin(radians(48.9193)) >> ) as result; >=20 >> This returned [22003] ERROR: input is out of range >=20 > Not too surprising, because (at least on my machine) >=20 > regression=3D# select cos(radians(48.9193)) > regression-# * cos(radians(48.9193)) + = sin(radians(48.9193)) > regression-# * sin(radians(48.9193)); > ?column? =20 > -------------------- > 1.0000000000000002 > (1 row) >=20 > Problems of this sort are inevitable when working with = finite-precision > math. >=20 > https://en.wikipedia.org/wiki/Round-off_error >=20 > regards, tom lane --Apple-Mail=_32B80C0F-EF6C-43B9-897F-047D64FEF61C Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii Hello= Tom!

I think is too = much for roundoff error

Found funny post about it:
https://randomascii.wordpress.com/2014/10/09/intel-underestimat= es-error-bounds-by-1-3-quintillion/
http://notabs.org/fpuaccuracy/index.htm



On 25 = Apr 2019, at 19:56, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Max = Lipsky <maxlipsky@gmail.com> writes:
SELECT acos(
=           cos(radians(48= .9193))
=           * = cos(radians(48.9193))
=           * = cos(radians(2.5431) - radians(2.5431))
=           + = sin(radians(48.9193))
=             * = sin(radians(48.9193))
=       ) as result;

This returned [22003] ERROR: input is out of range

Not too surprising, because (at = least on my machine)

regression=3D# select = cos(radians(48.9193))
regression-# =            * = cos(radians(48.9193)) +  sin(radians(48.9193))
regression-# =             &n= bsp;* sin(radians(48.9193));
=      ?column?      
--------------------
1.0000000000000002
(1 row)

Problems of this sort = are inevitable when working with finite-precision
math.

https://en.wikipedia.org/wiki/Round-off_error

regards, tom lane

= --Apple-Mail=_32B80C0F-EF6C-43B9-897F-047D64FEF61C--