[gnumeric-web] Floating point updates.

[Morten Welinder <mortenw src gnome org>]

commit 40ea974418e94a2869bbec667c3fe39197f18056
Author: Morten Welinder <terra gnome org>
Date:   Fri Feb 5 14:03:35 2021 -0500

    Floating point updates.
    
    Also retire old news.

 index.html            | 24 ------------------------
 numerical-issues.html | 11 ++++++-----
 past-news.html        | 27 +++++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 29 deletions(-)
---
diff --git a/index.html b/index.html
index b405640..129f198 100644
--- a/index.html
+++ b/index.html
@@ -73,30 +73,6 @@
            1.12.47 is out</a>.  Get it
            from <a href="download.html">here</a>!</p>
       </div>
-      <div class="newsitem">
-       <h2>
-         <span class="date">
-           <span class="month">Nov</span>
-           <span class="year">2019</span>
-         </span>
-         Gnumeric 1.12.46
-       </h2>
-       <p><a href="announcements/1.12/gnumeric-1.12.46.html">Gnumeric
-           1.12.46 is out</a>.  Get it
-           from <a href="download.html">here</a>!</p>
-      </div>
-      <div class="newsitem">
-       <h2>
-         <span class="date">
-           <span class="month">May</span>
-           <span class="year">2019</span>
-         </span>
-         Gnumeric 1.12.45
-       </h2>
-       <p><a href="announcements/1.12/gnumeric-1.12.45.html">Gnumeric
-           1.12.45 is out</a>.  Get it
-           from <a href="download.html">here</a>!</p>
-      </div>
       <div id="newsend">
        <p><a href="past-news.html">Older news...</a></p>
       </div>
diff --git a/numerical-issues.html b/numerical-issues.html
index eec4444..17d320b 100644
--- a/numerical-issues.html
+++ b/numerical-issues.html
@@ -61,7 +61,7 @@
          between representable numbers is much smaller for numbers
          close to zero than it is for large numbers.</li>
          <li>All integers up to about 10<sup>16</sup> can be
-         accurately represented.  That is the good news.</li>
+         precisely represented.  That is the good news.</li>
          <li><strong>The numbers 0.1, 0.01, ... cannot be precisely
          represented.</strong>  This is for the same reason that a
          desk calculator cannot precisely represent 1/3 but uses
@@ -91,7 +91,7 @@
 
        <p>For example, for the division 1/10 where the arguments ("1"
        and "10") are both precisely representable, we calculate the
-       mathematical value one-tenth are round that into the nearest
+       mathematical value one-tenth and round that into the nearest
        representable value which happens to be exactly
        0.1000000000000000000013552527156068805425093160010874271392822265625.
        That value clearly is a tiny bit bigger than one tenth in the
@@ -102,7 +102,7 @@
        example, one does not get zero as one might have hoped for.
        Each individual sub-result is subject to rounding to
        representable values, so we are really computing
-       r(r(0.3)-r(r(3)-r(0.1))) where "r" is the rounding operation.
+       r(r(0.3)-r(r(3)*r(0.1))) where "r" is the rounding operation.
        The end result is about -6*10<sup>-17</sup>.  That is an
        unpleasant result of working with finite-precision math.</p>
 
@@ -145,7 +145,7 @@
            when they are not.</li>
          <li>It becomes possible to have three numbers A1, A2, and
            A3, where A1=A2 and A2=A3, but A1&lt;&gt;A3.</li>
-         <li>It is possible for A1-5005=0 to be zero, but
+         <li>It is possible for A1-5005=0 and at the same time
            A1-5004-1&lt;&gt;0.</li>
          <li>It is possible to have A1=A2, but (say)
            TAN(A1)&lt;&gt;TAN(A2).</li>
@@ -170,7 +170,8 @@
        <p>The lack of an honest subtraction operation makes it hard
        to even test the accuracy of sheet-level functions.
        LibreOffice and OpenOffice will claim that a result matches a
-       reference value even when they do not.</p>
+         reference value even when they do not.  (Update: LibreOffice
+       nowadays has a function that allows raw subtraction.)</p>
       </div>
       <div class="generalitem">
        <h2><span class="gnumeric-bullet"></span>Alternate Number Systems</h2>
diff --git a/past-news.html b/past-news.html
index 9b26003..fdec8c9 100644
--- a/past-news.html
+++ b/past-news.html
@@ -32,6 +32,33 @@
          gets better as the years pass.  Welcome to our news cellar.</p>
       </div>
 
+      <div class="divider"><h2>2019</h2></div>
+
+      <div class="newsitem">
+       <h2>
+         <span class="date">
+           <span class="month">Nov</span>
+           <span class="year">2019</span>
+         </span>
+         Gnumeric 1.12.46
+       </h2>
+       <p><a href="announcements/1.12/gnumeric-1.12.46.html">Gnumeric
+           1.12.46 is out</a>.  Get it
+           from <a href="download.html">here</a>!</p>
+      </div>
+      <div class="newsitem">
+       <h2>
+         <span class="date">
+           <span class="month">May</span>
+           <span class="year">2019</span>
+         </span>
+         Gnumeric 1.12.45
+       </h2>
+       <p><a href="announcements/1.12/gnumeric-1.12.45.html">Gnumeric
+           1.12.45 is out</a>.  Get it
+           from <a href="download.html">here</a>!</p>
+      </div>
+
       <div class="divider"><h2>2018</h2></div>
 
       <div class="newsitem">