Bump version.

Author: kpeeters

README.rst

@@ -73,7 +73,7 @@ On Debian/Ubuntu you can install all that is needed with::
 
     sudo apt install git cmake python3-dev g++ libpcre3 libpcre3-dev libgmp3-dev \
           libgtkmm-3.0-dev libboost-all-dev libgmp-dev libsqlite3-dev uuid-dev  \
-          texlive texlive-latex-extra dvipng \
+          texlive texlive-latex-extra texlive-science dvipng \
           python3-matplotlib python3-mpmath python3-sympy python3-gmpy2
 
 (on Ubuntu 14.04 you need to replace `cmake` with `cmake3` and also

cmake/version.cmake

@@ -1,7 +1,7 @@
 set(CADABRA_VERSION_MAJOR 2)
 set(CADABRA_VERSION_MINOR 3)
-set(CADABRA_VERSION_PATCH 3)
-set(CADABRA_VERSION_TWEAK 2)
+set(CADABRA_VERSION_PATCH 4)
+set(CADABRA_VERSION_TWEAK 0)
 set(COPYRIGHT_YEARS "2001-2020")
 math(EXPR SYSTEM_BITS "${CMAKE_SIZEOF_VOID_P} * 8")
 find_program(GIT git PATHS ${GIT_DIR})

web2/cadabra2/source/faq.html

@@ -14,12 +14,22 @@ <h1>Frequently Asked Questions</h1>
 <h2>Installation</h2>
 
 <div class='faq_item'>
-  <input type="radio" name="collapse" id="q_01_01">    
+  <input type="radio" name="collapse" id="q_01_02">    
   <h3 class="handle">
-    <label for="q_01_01">Starting the Jupyter kernel gives an error.</label>
+    <label for="q_01_02">I get a 'Generic LaTeX error' when evaluating a cell.</label>
   </h3>
   <div class="content">
     <p>
+      This is typically caused by a missing LaTeX package. The error
+      dialog may give you a hint, but if you want to see the full
+      LaTeX error, take note of the file name in the error dialog, and
+      try to run that file through <tt>latex</tt> by hand.
+    </p>
+    <p>
+      The most common missing package is <tt>ytableau</tt>, which you
+      can get on Debian/Ubuntu systems by installing
+      the <tt>texlive-science</tt> package and on Fedora by
+      installing <tt>texlive-ytableau</tt>.
     </p>
   </div>
 </div>
@@ -33,7 +43,20 @@ <h3 class="handle">
     and independent indices?</label>
   </h3>
   <div class="content">
-    When you declare an index set, you can give it...
+    When you declare an index set, you can give it a <tt>position</tt>
+    property, which takes one of three
+    values <tt>free</tt>, <tt>fixed</tt>
+    or <tt>independent</tt>. Indices which are <tt>free</tt> can be
+    raised or lowered at will, and pairs can be at the same position;
+    these are typically used in case there is no metric associated to
+    them. Indices which have a different meaning when they are in
+    subscript or superscript position should, instead, be
+    declared <tt>fixed</tt>; this is what you would typically do in
+    special/general relativity, where the difference between an upper
+    or lower index is a factor of the metric. Cadabra can still swap
+    the position of pairs of indices in e.g. the <tt>canonicalise</tt>
+    function. If you want Cadabra to never touch the position of
+    indices in a set, declare them <tt>independent</tt>.
   </div>
 </div>
 

web2/cadabra2/source/help.html

@@ -16,6 +16,14 @@ <h2>Forum</h2>
   at <a href="mailto:[email protected]">[email protected]</a>. 
 </p>
 
+<h2>Frequently asked questions</h2>
+<p>
+  If you have a question, please first consult the list of
+  <a href="faq.html">frequently asked questions</a>; yours may be on
+  it already.
+</p>
+
+
 <h2>Reference guide</h2>
 <p>
   This reference guide is the place to go for a detailed specification