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921 lines
36 KiB
HTML
921 lines
36 KiB
HTML
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</head>
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<body>
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<div id="org-div-home-and-up">
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<a accesskey="h" href=""> UP </a>
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<a accesskey="H" href="index.html"> HOME </a>
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</div><div id="content">
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<h1 class="title">Introduction</h1>
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<div id="table-of-contents">
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<h2>Table of Contents</h2>
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<div id="text-table-of-contents">
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<ul>
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<li><a href="#orge10c4b9">1. Installing QMCkl</a>
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<ul>
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<li><a href="#org5aebc05">1.1. Installing from the released tarball (for end users)</a></li>
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<li><a href="#orgdee71f5">1.2. Installing from the source repository (for developers)</a></li>
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</ul>
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</li>
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<li><a href="#orgb40884f">2. Using QMCkl</a></li>
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<li><a href="#orgd76093c">3. Developing in QMCkl</a>
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<ul>
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<li><a href="#orgec7df6e">3.1. Literate programming</a></li>
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<li><a href="#org8f60b17">3.2. Source code editing</a></li>
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<li><a href="#orgeac549e">3.3. Choice of the programming language</a></li>
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<li><a href="#org22682de">3.4. Coding rules</a></li>
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<li><a href="#org908821b">3.5. Design of the library</a></li>
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<li><a href="#org2b6f7c9">3.6. Naming conventions</a></li>
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<li><a href="#org82b19d7">3.7. Application programming interface</a></li>
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<li><a href="#org89a575d">3.8. Global state</a></li>
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<li><a href="#orgebdb2c6">3.9. Headers</a></li>
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<li><a href="#org2570316">3.10. Low-level functions</a></li>
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<li><a href="#org0d425de">3.11. High-level functions</a></li>
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<li><a href="#org6252646">3.12. Numerical precision</a></li>
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<li><a href="#orgeee2dd0">3.13. Algorithms</a></li>
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</ul>
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</li>
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</ul>
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</div>
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</div>
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<div id="outline-container-orge10c4b9" class="outline-2">
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<h2 id="orge10c4b9"><span class="section-number-2">1</span> Installing QMCkl</h2>
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<div class="outline-text-2" id="text-1">
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<p>
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The latest version fo QMCkl can be downloaded
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<a href="https://github.com/TREX-CoE/qmckl/releases/latest">here</a>, and the source code is accessible on the
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<a href="https://github.com/TREX-CoE/qmckl">GitHub repository</a>.
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</p>
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</div>
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<div id="outline-container-org5aebc05" class="outline-3">
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<h3 id="org5aebc05"><span class="section-number-3">1.1</span> Installing from the released tarball (for end users)</h3>
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<div class="outline-text-3" id="text-1-1">
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<p>
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|
QMCkl is built with GNU Autotools, so the usual
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<code>configure ; make ; make check ; make install</code> scheme will be used.
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</p>
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<p>
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As usual, the C compiler can be specified with the <code>CC</code> variable
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and the Fortran compiler with the <code>FC</code> variable. The compiler
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options are defined using <code>CFLAGS</code> and <code>FCFLAGS</code>.
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</p>
|
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</div>
|
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</div>
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<div id="outline-container-orgdee71f5" class="outline-3">
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<h3 id="orgdee71f5"><span class="section-number-3">1.2</span> Installing from the source repository (for developers)</h3>
|
|
<div class="outline-text-3" id="text-1-2">
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|
<p>
|
|
To compile from the source repository, additional dependencies are
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|
required to generated the source files:
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</p>
|
|
<ul class="org-ul">
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|
<li>Emacs >= 26</li>
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|
<li>Autotools</li>
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<li>Python3</li>
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|
</ul>
|
|
|
|
<p>
|
|
When the repository is downloaded, the Makefile is not yet
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|
generated, as well as the configure script. <code>./autogen.sh</code> has
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|
to be executed first.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-orgb40884f" class="outline-2">
|
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<h2 id="orgb40884f"><span class="section-number-2">2</span> Using QMCkl</h2>
|
|
<div class="outline-text-2" id="text-2">
|
|
<p>
|
|
The <code>qmckl.h</code> header file installed in the <code>${prefix}/include</code> directory
|
|
has to be included in C codes when QMCkl functions are used:
|
|
</p>
|
|
|
|
<div class="org-src-container">
|
|
<pre class="src src-c"><span style="color: #483d8b;">#include</span> <span style="color: #8b2252;">"qmckl.h"</span>
|
|
</pre>
|
|
</div>
|
|
|
|
<p>
|
|
In Fortran programs, the <code>qmckl_f.f90</code> installed in
|
|
<code>${prefix}/share/qmckl/fortran</code> interface file should be copied in the source
|
|
code using the library, and the Fortran codes should use the <code>qmckl</code> module as
|
|
</p>
|
|
|
|
<div class="org-src-container">
|
|
<pre class="src src-f90"><span style="color: #a020f0;">use</span> <span style="color: #0000ff;">qmckl</span>
|
|
</pre>
|
|
</div>
|
|
|
|
<p>
|
|
Both files are located in the <code>include/</code> directory.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-orgd76093c" class="outline-2">
|
|
<h2 id="orgd76093c"><span class="section-number-2">3</span> Developing in QMCkl</h2>
|
|
<div class="outline-text-2" id="text-3">
|
|
</div>
|
|
<div id="outline-container-orgec7df6e" class="outline-3">
|
|
<h3 id="orgec7df6e"><span class="section-number-3">3.1</span> Literate programming</h3>
|
|
<div class="outline-text-3" id="text-3-1">
|
|
<p>
|
|
In a traditional source code, most of the lines of source files of a program
|
|
are code, scripts, Makefiles, and only a few lines are comments explaining
|
|
parts of the code that are non-trivial to understand. The documentation of
|
|
the prorgam is usually written in a separate directory, and is often outdated
|
|
compared to the code.
|
|
</p>
|
|
|
|
<p>
|
|
Literate programming is a different approach to programming,
|
|
where the program is considered as a publishable-quality document. Most of
|
|
the lines of the source files are text, mathematical formulas, tables,
|
|
figures, <i>etc</i>, and the lines of code are just the translation in a computer
|
|
language of the ideas and algorithms expressed in the text. More importantly,
|
|
the "document" is structured like a text document with sections, subsections,
|
|
a bibliography, a table of contents <i>etc</i>, and the place where pieces of code
|
|
appear are the places where they should belong for the reader to understand
|
|
the logic of the program, not the places where the compiler expects to find
|
|
them. Both the publishable-quality document and the binary executable are
|
|
produced from the same source files.
|
|
</p>
|
|
|
|
<p>
|
|
Literate programming is particularly well adapted in this context, as the
|
|
central part of this project is the documentation of an API. The
|
|
implementation of the algorithms is just an expression of the algorithms in a
|
|
language that can be compiled, so that the correctness of the algorithms can
|
|
be tested.
|
|
</p>
|
|
|
|
<p>
|
|
We have chosen to write the source files in <a href="https://karl-voit.at/2017/09/23/orgmode-as-markup-only/">org-mode</a> format,
|
|
as any text editor can be used to edit org-mode files. To
|
|
produce the documentation, there exists multiple possibilities to convert
|
|
org-mode files into different formats such as HTML or PDF. The source code is
|
|
easily extracted from the org-mode files invoking the Emacs text editor from
|
|
the command-line in the <code>Makefile</code>, and then the produced files are compiled.
|
|
Moreover, within the Emacs text editor the source code blocks can be executed
|
|
interactively, in the same spirit as Jupyter notebooks.
|
|
</p>
|
|
|
|
<p>
|
|
Note that Emacs is not needed for end users because the distributed
|
|
tarball contains the generated source code.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org8f60b17" class="outline-3">
|
|
<h3 id="org8f60b17"><span class="section-number-3">3.2</span> Source code editing</h3>
|
|
<div class="outline-text-3" id="text-3-2">
|
|
<p>
|
|
For a tutorial on literate programming with org-mode, follow <a href="http://www.howardism.org/Technical/Emacs/literate-programming-tutorial.html">this link</a>.
|
|
</p>
|
|
|
|
<p>
|
|
Any text editor can be used to edit org-mode files. For a better
|
|
user experience Emacs is recommended. For users hating Emacs, it
|
|
is good to know that Emacs can behave like Vim when switched into
|
|
``Evil'' mode.
|
|
</p>
|
|
|
|
<p>
|
|
In the <code>tools/init.el</code> file, we provide a minimal Emacs configuration
|
|
file for vim users. This file should be copied into <code>.emacs.d/init.el</code>.
|
|
</p>
|
|
|
|
<p>
|
|
For users with a preference for Jupyter notebooks, we also provide the
|
|
<code>tools/nb_to_org.sh</code> script can convert jupyter notebooks into org-mode
|
|
files.
|
|
</p>
|
|
|
|
<p>
|
|
Note that pandoc can be used to convert multiple markdown formats into
|
|
org-mode.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-orgeac549e" class="outline-3">
|
|
<h3 id="orgeac549e"><span class="section-number-3">3.3</span> Choice of the programming language</h3>
|
|
<div class="outline-text-3" id="text-3-3">
|
|
<p>
|
|
Most of the codes of the <a href="https://trex-coe.eu">TREX CoE</a> are written in Fortran with some
|
|
scripts in Bash and Python. Outside of the CoE, Fortran is also
|
|
important in QMC codes (Casino, Amolqc), and other important
|
|
languages used by the community are C and C++ (QMCPack, QWalk),
|
|
Julia and Rust are gaining in popularity. We want QMCkl to be
|
|
compatible with all of these languages, so the QMCkl API has to be
|
|
compatible with the C language since libraries with a C-compatible
|
|
API can be used in every other language.
|
|
</p>
|
|
|
|
<p>
|
|
High-performance versions of QMCkl, with the same API, can be
|
|
rewritten by HPC experts. These optimized libraries will be tuned
|
|
for specific architectures, among which we can cite x86 based
|
|
processors, and GPU accelerators. Nowadays, the most efficient
|
|
software tools to take advantage of low-level features
|
|
(intrinsics, prefetching, aligned or pinned memory allocation,
|
|
…) are for C++ developers. It is highly probable that optimized
|
|
implementations will be written in C++, but as the API is
|
|
C-compatible this doesn't pose any problem for linking the library
|
|
in other languages.
|
|
</p>
|
|
|
|
<p>
|
|
Fortran is one of the most common languages used by the community,
|
|
and is simple enough to make the algorithms readable both by
|
|
experts in QMC, and experts in HPC. Hence we propose in this
|
|
pedagogical implementation of QMCkl to use Fortran to express the
|
|
QMC algorithms. However, for internal functions related to system
|
|
programming, the C language is more natural than Fortran.
|
|
</p>
|
|
|
|
<p>
|
|
As QMCkl appears like a C library, for each Fortran function there
|
|
is an <code>iso_c_binding</code> interface to make the Fortran function
|
|
callable from C. It is this C interface which is exposed to the
|
|
user. As a consequence, the Fortran users of the library never
|
|
call directly the Fortran routines, but call instead the C binding
|
|
function and an <code>iso_c_binding</code> is still required:
|
|
</p>
|
|
|
|
<pre class="example">
|
|
ISO_C_BINDING ISO_C_BINDING
|
|
Fortran ---------------> C ---------------> Fortran
|
|
</pre>
|
|
|
|
<p>
|
|
The name of the Fortran source files should end with <code>_f.f90</code> to
|
|
be properly handled by the <code>Makefile</code> and to avoid collision of
|
|
object files (<code>*.o</code>) with the compiled C source files. The names
|
|
of the functions defined in Fortran should be the same as those
|
|
exposed in the API suffixed by <code>_f</code>.
|
|
</p>
|
|
|
|
<p>
|
|
For more guidelines on using Fortran to generate a C interface, see
|
|
<a href="http://fortranwiki.org/fortran/show/Generating+C+Interfaces">this link</a>.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org22682de" class="outline-3">
|
|
<h3 id="org22682de"><span class="section-number-3">3.4</span> Coding rules</h3>
|
|
<div class="outline-text-3" id="text-3-4">
|
|
<p>
|
|
The authors should follow the recommendations of the C99
|
|
<a href="https://wiki.sei.cmu.edu/confluence/display/c/SEI+CERT+C+Coding+Standard">SEI+CERT C Coding Standard</a>.
|
|
</p>
|
|
|
|
<p>
|
|
Compliance can be checked with <code>cppcheck</code> as:
|
|
</p>
|
|
|
|
<div class="org-src-container">
|
|
<pre class="src src-bash">cppcheck --addon=cert --enable=all *.c &> cppcheck.out
|
|
# <span style="color: #b22222;">or</span>
|
|
make cppcheck ; cat cppcheck.out
|
|
</pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org908821b" class="outline-3">
|
|
<h3 id="org908821b"><span class="section-number-3">3.5</span> Design of the library</h3>
|
|
<div class="outline-text-3" id="text-3-5">
|
|
<p>
|
|
The proposed API should allow the library to: deal with memory transfers
|
|
between CPU and accelerators, and to use different levels of floating-point
|
|
precision. We chose a multi-layered design with low-level and high-level
|
|
functions (see below).
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org2b6f7c9" class="outline-3">
|
|
<h3 id="org2b6f7c9"><span class="section-number-3">3.6</span> Naming conventions</h3>
|
|
<div class="outline-text-3" id="text-3-6">
|
|
<p>
|
|
To avoid namespace collisions, we use <code>qmckl_</code> as a prefix for all exported
|
|
functions and variables. All exported header files should have a file name
|
|
prefixed with <code>qmckl_</code>.
|
|
</p>
|
|
|
|
<p>
|
|
If the name of the org-mode file is <code>xxx.org</code>, the name of the
|
|
produced C files should be <code>xxx.c</code> and <code>xxx.h</code> and the name of the
|
|
produced Fortran file should be <code>xxx.f90</code>.
|
|
</p>
|
|
|
|
<p>
|
|
In the names of the variables and functions, only the singular
|
|
form is allowed.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org82b19d7" class="outline-3">
|
|
<h3 id="org82b19d7"><span class="section-number-3">3.7</span> Application programming interface</h3>
|
|
<div class="outline-text-3" id="text-3-7">
|
|
<p>
|
|
In the C language, the number of bits used by the integer types can change
|
|
from one architecture to another one. To circumvent this problem, we choose to
|
|
use the integer types defined in <code><stdint.h></code> where the number of bits used for
|
|
the integers are fixed.
|
|
</p>
|
|
|
|
<p>
|
|
To ensure that the library will be easily usable in <i>any</i> other language
|
|
than C, we restrict the data types in the interfaces to the following:
|
|
</p>
|
|
<ul class="org-ul">
|
|
<li>32-bit and 64-bit integers, scalars and and arrays (<code>int32_t</code> and <code>int64_t</code>)</li>
|
|
<li>32-bit and 64-bit floats, scalars and and arrays (<code>float</code> and <code>double</code>)</li>
|
|
<li>Pointers are always casted into 64-bit integers, even on legacy 32-bit architectures</li>
|
|
<li>ASCII strings are represented as a pointers to character arrays
|
|
and terminated by a <code>'\0'</code> character (C convention).</li>
|
|
<li>Complex numbers can be represented by an array of 2 floats.</li>
|
|
<li>Boolean variables are stored as integers, <code>1</code> for <code>true</code> and <code>0</code> for <code>false</code></li>
|
|
<li>Floating point variables should be by default <code>double</code> unless explicitly mentioned</li>
|
|
<li>integers used for counting should always be <code>int64_t</code></li>
|
|
</ul>
|
|
|
|
<p>
|
|
To facilitate the use in other languages than C, we will provide some
|
|
bindings in other languages in other repositories.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org89a575d" class="outline-3">
|
|
<h3 id="org89a575d"><span class="section-number-3">3.8</span> Global state</h3>
|
|
<div class="outline-text-3" id="text-3-8">
|
|
<p>
|
|
Global variables should be avoided in the library, because it is
|
|
possible that one single program needs to use multiple instances
|
|
of the library. To solve this problem we propose to use a pointer
|
|
to a <a href="./qmckl_context.html"><code>context</code></a> variable, built by the library with the
|
|
<code>qmckl_context_create</code> function. The <a id="orgf87752d">=context=</a> contains the global
|
|
state of the library, and is used as the first argument of many
|
|
QMCkl functions.
|
|
</p>
|
|
|
|
<p>
|
|
The internal structure of the context is not specified, to give a
|
|
maximum of freedom to the different implementations. Modifying
|
|
the state is done by setters and getters, prefixed by
|
|
<code>qmckl_set_</code> an <code>qmckl_get_</code>.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-orgebdb2c6" class="outline-3">
|
|
<h3 id="orgebdb2c6"><span class="section-number-3">3.9</span> Headers</h3>
|
|
<div class="outline-text-3" id="text-3-9">
|
|
<p>
|
|
A single <code>qmckl.h</code> header to be distributed by the library
|
|
is built by concatenating some of the produced header files.
|
|
To facilitate building the <code>qmckl.h</code> file, we separate types from
|
|
function declarations in headers. Types should be defined in header
|
|
files suffixed by <code>_type.h</code>, and functions in files suffixed by
|
|
<code>_func.h</code>.
|
|
As these files will be concatenated in a single file, they should
|
|
not be guarded by <code>#ifndef *_H</code>, and they should not include other
|
|
produced headers.
|
|
</p>
|
|
|
|
<p>
|
|
Some particular types that are not exported need to be known by the
|
|
context, and there are some functions to update instances of these
|
|
types contained inside the context. For example, a
|
|
<code>qmckl_numprec_struct</code> is present in the context, and the function
|
|
<code>qmckl_set_numprec_range</code> takes a context as a parameter, and set a
|
|
value in the <code>qmckl_numprec_struct</code> contained in the context.
|
|
Because of these intricate dependencies, a private header is
|
|
created, containing the <code>qmckl_numprec_struct</code>. This header is
|
|
included in the private header file which defines the type of the
|
|
context. Header files for private types are suffixed by <code>_private_type.h</code>
|
|
and header files for private functions are suffixed by <code>_private_func.h</code>.
|
|
Fortran interfaces should also be written in the <code>*fh_func.f90</code> file,
|
|
and the types definitions should be written in the <code>*fh_type.f90</code> file.
|
|
</p>
|
|
|
|
<table border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
|
|
|
|
|
|
<colgroup>
|
|
<col class="org-left" />
|
|
|
|
<col class="org-left" />
|
|
|
|
<col class="org-left" />
|
|
</colgroup>
|
|
<thead>
|
|
<tr>
|
|
<th scope="col" class="org-left">File</th>
|
|
<th scope="col" class="org-left">Scope</th>
|
|
<th scope="col" class="org-left">Description</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody>
|
|
<tr>
|
|
<td class="org-left"><code>*_type.h</code></td>
|
|
<td class="org-left">Public</td>
|
|
<td class="org-left">Type definitions</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="org-left"><code>*_func.h</code></td>
|
|
<td class="org-left">Public</td>
|
|
<td class="org-left">Function definitions</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="org-left"><code>*_private_type.h</code></td>
|
|
<td class="org-left">Private</td>
|
|
<td class="org-left">Type definitions</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="org-left"><code>*_private_func.h</code></td>
|
|
<td class="org-left">Private</td>
|
|
<td class="org-left">Function definitions</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="org-left"><code>*fh_type.f90</code></td>
|
|
<td class="org-left">Public</td>
|
|
<td class="org-left">Fortran type definitions</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="org-left"><code>*fh_func.f90</code></td>
|
|
<td class="org-left">Public</td>
|
|
<td class="org-left">Fortran function definitions</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org2570316" class="outline-3">
|
|
<h3 id="org2570316"><span class="section-number-3">3.10</span> Low-level functions</h3>
|
|
<div class="outline-text-3" id="text-3-10">
|
|
<p>
|
|
Low-level functions are very simple functions which are leaves of
|
|
the function call tree (they don't call any other QMCkl function).
|
|
</p>
|
|
|
|
<p>
|
|
These functions are <i>pure</i>, and unaware of the QMCkl
|
|
<a href="#orgf87752d"><code>context</code></a>. They are not allowed to allocate/deallocate memory, and
|
|
if they need temporary memory it should be provided in input.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org0d425de" class="outline-3">
|
|
<h3 id="org0d425de"><span class="section-number-3">3.11</span> High-level functions</h3>
|
|
<div class="outline-text-3" id="text-3-11">
|
|
<p>
|
|
High-level functions are at the top of the function call tree.
|
|
They are able to choose which lower-level function to call
|
|
depending on the required precision, and do the corresponding type
|
|
conversions. These functions are also responsible for allocating
|
|
temporary storage, to simplify the use of accelerators.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-org6252646" class="outline-3">
|
|
<h3 id="org6252646"><span class="section-number-3">3.12</span> Numerical precision</h3>
|
|
<div class="outline-text-3" id="text-3-12">
|
|
<p>
|
|
The minimal number of bits of precision required for a function
|
|
should be given as an input of low-level computational
|
|
functions. This input will be used to define the values of the
|
|
different thresholds that might be used to avoid computing
|
|
unnecessary noise. High-level functions will use the precision
|
|
specified in the <a href="#orgf87752d"><code>context</code></a> variable.
|
|
</p>
|
|
|
|
<p>
|
|
In order to automatize numerical accuracy tests, QMCkl uses
|
|
<a href="https://github.com/verificarlo/verificarlo">Verificarlo</a> and its CI functionality. You can read Verificarlo CI's
|
|
documentation at the <a href="https://github.com/verificarlo/verificarlo/blob/master/doc/06-Postprocessing.md#verificarlo-ci">following link</a>. Reading it is advised to
|
|
understand the remainder of this section.
|
|
</p>
|
|
|
|
<p>
|
|
To enable support for Verificarlo CI tests when building the
|
|
library, use the following configure command :
|
|
</p>
|
|
|
|
<div class="org-src-container">
|
|
<pre class="src src-bash">./configure <span style="color: #a0522d;">CC</span>=verificarlo-f <span style="color: #a0522d;">FC</span>=verificarlo-f --host=x86_64 --enable-vfc_ci
|
|
</pre>
|
|
</div>
|
|
|
|
<p>
|
|
Note that this does require an install of Verificarlo <b>with
|
|
Fortran support</b>. Enabling the support for CI will define the
|
|
<code>VFC_CI</code> preprocessor variable which use will be explained now.
|
|
</p>
|
|
|
|
<p>
|
|
As explained in the documentation, Verificarlo CI uses a probes
|
|
system to export variables from test programs to the tools itself.
|
|
To make tests easier to use, QMCkl has its own interface to the
|
|
probes system. To make the system very easy to use, these functions
|
|
are always defined, but will behave differently depending on the
|
|
<code>VFC_CI</code> preprocessor variable. There are 3 functions at your
|
|
disposal. When the CI is enabled, they will place a <code>vfc_ci</code> probe
|
|
as if calling <code>vfc_probes</code> directly. Otherwise, they will either do
|
|
nothing or perform a check on the tested value and return its result
|
|
as a boolean that you are free to use or ignore.
|
|
Here are these 3 functions :
|
|
</p>
|
|
|
|
<ul class="org-ul">
|
|
<li><code>qmckl_probe</code> : place a normal probe witout any check. Won't do anything when <code>vfc_ci</code> is disabled (false is returned).</li>
|
|
<li><code>qmckl_probe_check</code> : place a probe with an absolute check. If <code>vfc_ci</code> is disabled, this will return the result of an absolute check (|val - ref| < accuracy target ?). If the check fails, true is returned (false otherwise).</li>
|
|
<li><code>qmckl_probe_check_relative</code> : place a probe with a relative check. If <code>vfc_ci</code> is disabled, this will return the result of a relative check (|val - ref| / ref < accuracy target?). If the check fails, true is returned (false otherwise).</li>
|
|
</ul>
|
|
|
|
|
|
<p>
|
|
If you need more detail on these functions or their Fortran
|
|
interfaces, have a look at the <code>tools/qmckl_probes</code> files.
|
|
</p>
|
|
|
|
<p>
|
|
Finally, if you need to add a QMCkl kernel to the CI tests
|
|
or modify an existing one, you should pay attention to the
|
|
following points :
|
|
</p>
|
|
|
|
<ul class="org-ul">
|
|
<li>you should add the new kernel to the <code>vfc_tests_config.json</code> file, which controls the backends and repetitions for each executable. More details can be found in the <code>vfc_ci</code> documentation.</li>
|
|
|
|
<li>in order to call the <code>qmckl_probes</code> functions from Fortran, import the <code>qmckl_probes_f</code> module.</li>
|
|
|
|
<li>if your tests include some asserts that rely on accurate FP values, you should probably wrap them inside a <code>#ifndef VFC_CI</code> statement, as the asserts would otherwise risk to fail when executed with the different Verificarlo backends.</li>
|
|
</ul>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="outline-container-orgeee2dd0" class="outline-3">
|
|
<h3 id="orgeee2dd0"><span class="section-number-3">3.13</span> Algorithms</h3>
|
|
<div class="outline-text-3" id="text-3-13">
|
|
<p>
|
|
Reducing the scaling of an algorithm usually implies also reducing
|
|
its arithmetic complexity (number of flops per byte). Therefore,
|
|
for small sizes \(\mathcal{O}(N^3)\) and \(\mathcal{O}(N^2)\)
|
|
algorithms are better adapted than linear scaling algorithms. As
|
|
QMCkl is a general purpose library, multiple algorithms should be
|
|
implemented adapted to different problem sizes.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div id="postamble" class="status">
|
|
<p class="author">Author: TREX CoE</p>
|
|
<p class="date">Created: 2022-07-11 Mon 07:46</p>
|
|
<p class="validation"><a href="http://validator.w3.org/check?uri=referer">Validate</a></p>
|
|
</div>
|
|
</body>
|
|
</html>
|