Update to v0.4v0.4

  feature: compute the 2-point correlation function in easyeq.

  feature: compute the Fourier transform of the 2-point correlation function
           in anyeq and easyeq.

  feature: compute the local maximum of the 2-point correlation function and
           its Fourier transform.

  feature: compute the compressibility for anyeq.

  feature: allow for linear spacing of rho's.

  feature: print the scattering length.

  change: ux and uk now return real numbers.

  fix: error in the computation of the momentum distribution: wrong
       definition of delta functions.

  fix: various minor bugs.

  optimization: assign explicit types to variables.

6 files changed, 67 insertions, 6 deletions

diff --git a/doc/libs/code.sty b/doc/libs/code.sty
index d4f4070..e067dfe 100644
--- a/doc/libs/code.sty
+++ b/doc/libs/code.sty
@@ -1,4 +1,4 @@
-%% Copyright 2021 Ian Jauslin
+%% Copyright 2021-2023 Ian Jauslin
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
diff --git a/doc/libs/dlmf.sty b/doc/libs/dlmf.sty
index f435e96..f66157b 100644
--- a/doc/libs/dlmf.sty
+++ b/doc/libs/dlmf.sty
@@ -1,4 +1,4 @@
-%% Copyright 2021 Ian Jauslin
+%% Copyright 2021-2023 Ian Jauslin
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
diff --git a/doc/libs/ian.cls b/doc/libs/ian.cls
index f29e6bd..762f679 100644
--- a/doc/libs/ian.cls
+++ b/doc/libs/ian.cls
@@ -219,6 +219,7 @@
   % counters
   \stepcounter{subsectioncount}
   \setcounter{subsubsectioncount}{0}
+  \setcounter{subsubsubsectioncount}{0}
   \ifsubsectionsineq
     \setcounter{seqcount}0
   \fi
@@ -268,6 +269,7 @@
 \def\subsubsection#1{
   % counters
   \stepcounter{subsubsectioncount}
+  \setcounter{subsubsubsectioncount}{0}
 
   % space before subsubsection (if not first)
   \ifnum\thesubsubsectioncount>1
@@ -302,6 +304,49 @@
   \medskip\penalty10000
 }
 
+%% subsubsubsection
+% counter
+\newcounter{subsubsubsectioncount}
+% space before subsubsubsection
+\newlength\subsubsubsecskip
+\setlength\subsubsubsecskip{20pt}
+\def\subsubsubsection#1{
+  % counters
+  \stepcounter{subsubsubsectioncount}
+
+  % space before subsubsubsection (if not first)
+  \ifnum\thesubsubsubsectioncount>1
+    \vskip\subsubsubsecskip
+    \penalty-500
+  \fi
+
+  % hyperref anchor
+  \hrefanchor
+  % define tag (for \label)
+  \xdef\tag{\sectionprefix\thesectioncount.\thesubsectioncount.\thesubsubsectioncount.\thesubsubsubsectioncount}
+
+  % get widths
+  \def\@secnum{{\bf\hskip1.5cm\sectionprefix\thesectioncount.\thesubsectioncount.\thesubsubsectioncount.\thesubsubsubsectioncount.\hskip5pt}}
+  \settowidth\secnumwidth{\@secnum}
+  \setlength\sectitlewidth\textwidth
+  \addtolength\sectitlewidth{-\secnumwidth}
+  % print name
+  \parbox{\textwidth}{
+  \@secnum
+  \parbox[t]{\sectitlewidth}{\bf #1}}
+
+  % write to table of contents
+  \iftoc
+    % save lncount in aux variable which is written to toc
+    \immediate\write\tocoutput{\noexpand\expandafter\noexpand\edef\noexpand\csname toc@subsubsubsec.\thesectioncount.\thesubsectioncount.\thesubsubsectioncount.\thesubsubsubsectioncount\endcsname{\thelncount}}
+    \write\tocoutput{\noexpand\tocsubsubsubsection{#1}{\thepage}}
+  \fi
+
+  % space
+  \par\penalty10000
+  \medskip\penalty10000
+}
+
 %% itemize
 \newlength\itemizeskip
 % left margin for items
@@ -638,6 +683,7 @@
   \stepcounter{tocsectioncount}
   \setcounter{tocsubsectioncount}{0}
   \setcounter{tocsubsubsectioncount}{0}
+  \setcounter{tocsubsubsubsectioncount}{0}
   % write
   \smallskip\hyperlink{ln.\csname toc@sec.\thetocsectioncount\endcsname}{{\bf \tocsectionprefix\thetocsectioncount}.\hskip5pt {\color{blue}#1}\leaderfill#2}\par
 }
@@ -645,6 +691,7 @@
 \def\tocsubsection #1#2{
   \stepcounter{tocsubsectioncount}
   \setcounter{tocsubsubsectioncount}{0}
+  \setcounter{tocsubsubsubsectioncount}{0}
   % write
   {\hskip10pt\hyperlink{ln.\csname toc@subsec.\thetocsectioncount.\thetocsubsectioncount\endcsname}{{\bf \thetocsectioncount.\thetocsubsectioncount}.\hskip5pt {\color{blue}\small #1}\leaderfill#2}}\par
 }
@@ -654,6 +701,12 @@
   % write
   {\hskip20pt\hyperlink{ln.\csname toc@subsubsec.\thetocsectioncount.\thetocsubsectioncount.\thetocsubsubsectioncount\endcsname}{{\bf \thetocsectioncount.\thetocsubsectioncount.\thetocsubsubsectioncount}.\hskip5pt {\color{blue}\small #1}\leaderfill#2}}\par
 }
+\newcounter{tocsubsubsubsectioncount}
+\def\tocsubsubsubsection #1#2{
+  \stepcounter{tocsubsubsubsectioncount}
+  % write
+  {\hskip30pt\hyperlink{ln.\csname toc@subsubsubsec.\thetocsectioncount.\thetocsubsectioncount.\thetocsubsubsectioncount.\thetocsubsubsubsectioncount\endcsname}{{\bf \thetocsectioncount.\thetocsubsectioncount.\thetocsubsubsectioncount.\thetocsubsubsubsectioncount}.\hskip5pt {\color{blue}\small #1}\leaderfill#2}}\par
+}
 \def\tocappendices{
   \medskip
   \setcounter{tocsectioncount}0
diff --git a/doc/libs/iantheo.sty b/doc/libs/iantheo.sty
index 1945a5f..31842a4 100644
--- a/doc/libs/iantheo.sty
+++ b/doc/libs/iantheo.sty
@@ -1,4 +1,4 @@
-%% Copyright 2021 Ian Jauslin
+%% Copyright 2021-2023 Ian Jauslin
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
diff --git a/doc/libs/largearray.sty b/doc/libs/largearray.sty
index cf9075f..3a8762e 100644
--- a/doc/libs/largearray.sty
+++ b/doc/libs/largearray.sty
@@ -1,4 +1,4 @@
-%% Copyright 2021 Ian Jauslin
+%% Copyright 2021-2023 Ian Jauslin
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
diff --git a/doc/libs/point.sty b/doc/libs/point.sty
index a396d1c..796e0d2 100644
--- a/doc/libs/point.sty
+++ b/doc/libs/point.sty
@@ -1,4 +1,4 @@
-%% Copyright 2021 Ian Jauslin
+%% Copyright 2021-2023 Ian Jauslin
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -33,12 +33,15 @@
 \newif\ifresetatsubsubsection
 \DeclareOption{reset_at_subsubsection}{\resetatsubsubsectiontrue}
 \DeclareOption{no_reset_at_subsubsection}{\resetatsubsubsectionfalse}
+\newif\ifresetatsubsubsubsection
+\DeclareOption{reset_at_subsubsubsection}{\resetatsubsubsubsectiontrue}
+\DeclareOption{no_reset_at_subsubsubsection}{\resetatsubsubsubsectionfalse}
 \newif\ifresetattheo
 \DeclareOption{reset_at_theo}{\resetattheotrue}
 \DeclareOption{no_reset_at_theo}{\resetattheofalse}
 
 \def\point@defaultoptions{
-  \ExecuteOptions{reset_at_section, reset_at_subsection, reset_at_subsubsection, no_reset_at_theo}
+  \ExecuteOptions{reset_at_section, reset_at_subsection, reset_at_subsubsection, reset_at_subsubsubsection, no_reset_at_theo}
   \ProcessOptions
 
   %% reset at every new section
@@ -56,6 +59,11 @@
     \let\point@oldsubsubsection\subsubsection
     \gdef\subsubsection{\resetpointcounter\point@oldsubsubsection}
   \fi
+  %% reset at every new subsubsubsection
+  \ifresetatsubsubsubsection
+    \let\point@oldsubsubsubsection\subsubsubsection
+    \gdef\subsubsubsection{\resetpointcounter\point@oldsubsubsubsection}
+  \fi
 
   %% reset at every new theorem
   \ifresetattheo