foo

README.md

@@ -1,122 +1,9 @@
 # C++ Datetime library
 
-## Introduction
-
 ggdatetime is a C++ library to assist date and time related computations in 
 Geodesy related fields.
 
 [![clang-format Check](https://github.com/DSOlab/ggdatetime/actions/workflows/clang-format-check.yml/badge.svg)](https://github.com/DSOlab/ggdatetime/actions/workflows/clang-format-check.yml)
 [![Linux CI build](https://github.com/DSOlab/ggdatetime/actions/workflows/cpp-linux-build.yml/badge.svg)](https://github.com/DSOlab/ggdatetime/actions/workflows/cpp-linux-build.yml)
 
-## Compilation / Installation
-
-Source code is ISO C++17. Compilation should be trivial using any C++ compiler
-[supporting the c++17](https://en.wikipedia.org/wiki/C%2B%2B17#Compiler_support) 
-standard (option `-std=c++17` in gcc and clang).
-
-**October 2021** Source code can also be compiled using the latest 
-[C++ 20 standard](https://en.cppreference.com/w/cpp/20). 
-
-> Since December 2021, the build system has been changed from 
-> [GNU Autotools](https://www.gnu.org/software/automake/manual/html_node/Autotools-Introduction.html)
-> to [scons](https://scons.org/). 
-> Since September 2024 the build system has been changed to [cmake](https://cmake.org/)
-
-### Compile and install
-
-Supposing you are located in the top-level directory:
-
-```
-## to build in a folder named "build":
-$> cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
-$> cmake --build build --target all --config Release -- -j4
-## (Optional) run tests
-$> ctest --test-dir build
-## Install, system-wide (needs root)
-$> cd build && sudo make install
-```
-
-## Compilation Options
-
-### `ALLOW_DT_INTEGRAL_MATH`
-
-This option will allow (some) selected operations between DateTime fundamental 
-types and integral numbers. For example, the following snippet would be valid:
-
-```
-Modified_julian_day mjd (123);
-mjd += 1;
-// Now mjd's internal member, will have a value of 124.
-```
-
-## Examples
-
-Consult the test programs source code in the 
-[test folder](https://github.com/xanthospap/libsinex/tree/main/test) 
-for examples on how to use the library.
-
-## Developers
-
-Take a look at the [LLVM Coding Standards](https://llvm.org/docs/CodingStandards.html) 
-and if possible stick to it. 
-
-Use [clang-format](https://clang.llvm.org/docs/ClangFormat.html)
-to format you code before commiting; if you try to commit with non-acceptable 
-code format, the CI system will fail.
-
-## The Library
-
-### Nomenclature
-
-* *Julian year* 365.25 days
-* *Julian century* 36525 days
-
-*Julian date* (JD) is a continuous count of days (JD zero is located about 7000 years ago).
-Because of the unwieldy size of Julian Dates and the awkwardness of the half-day 
-offset, it is accepted practice to remove the leading ‘24’ and the trailing ‘.5’, 
-producing what is called the *Modified Julian Date*, i.e.
-$ MJD = JD − 2,400,000.5 $
-
-In the library, this constant is named `ds::MJD0_JD = 2400000.5e0`, i.e. the
-*Julian Date of Modified Julian Date zero*.
-
-*Julian epoch* is a convinient way of representing an epoch as fractional years. 
-It uses the *Julian year* of exactly 365.25 days, and the *TT* time scale; 
-Julian epoch 2000.0 is defined to be 2000 January 1.5 (i.e. 2000 January 1d 12h), 
-which is JD 2,451,545.0 (i.e. `dso::J2000_JD`) or MJD 51,544.5 (i.e. `dso::J2000_MJD`). 
-Julian epoch is usually denoted as *“J2000.0”*.
-
-### Precision
-
-**Transforming from `datetime<T>` to `TwoPartDate`s**
-
-Transforming from a `datetime<nanoseconds>` instance to an instance of type 
-`TwoPartDate` preserves a precision better than 2e-2 nanoseconds. This is verified 
-by running the test program [unit_tests/tpdates1.cpp](test/unit_tests/tpdates1.cpp)
-
-Transforming from a `datetime<microseconds>` instance to an instance of type 
-`TwoPartDate` preserves a precision better than 2e-5 microseconds. This is verified 
-by running the test program [unit_tests/tpdates2.cpp](test/unit_tests/tpdates2.cpp)
-
-Transforming from a `datetime<milliseconds>` instance to an instance of type 
-`TwoPartDate` preserves a precision better than 2e-8 milliseconds. This is verified 
-by running the test program [unit_tests/tpdates3.cpp](test/unit_tests/tpdates3.cpp)
-
-Transforming from a `datetime<seconds>` instance to an instance of type 
-`TwoPartDate` preserves a precision better than 2e-12 seconds. This is verified 
-by running the test program [unit_tests/tpdates4.cpp](test/unit_tests/tpdates4.cpp)
-
-**Transforming from/to Julian Epoch**
-
-Transforming from a `TwoPartDate` to a *Julian Epoch* and back, preserves an 
-accuracy of `~1e-5` seconds. This is verified by running the test program 
-[test/sofa/epj_date.cpp](test/sofa/epj_date.cpp).
-
-## Authors
-
-Dionysos Satellite Observatory,
-School of Rural Surveying and Geoinformatics Engineering,
-National Technical University of Athens
-
-Send bugs to:
-Xanthos Papanikolaou, [email protected]
+[see tutorial](doc/tutorial.md)

doc/tutorial.md

@@ -1,6 +1,9 @@
 # DSO's Datetime Library for Satellite Geodesy
 -----------------------------------------------
 
+[![clang-format Check](https://github.com/DSOlab/ggdatetime/actions/workflows/clang-format-check.yml/badge.svg)](https://github.com/DSOlab/ggdatetime/actions/workflows/clang-format-check.yml)
+[![Linux CI build](https://github.com/DSOlab/ggdatetime/actions/workflows/cpp-linux-build.yml/badge.svg)](https://github.com/DSOlab/ggdatetime/actions/workflows/cpp-linux-build.yml)
+
 ## Installation
 
 Source code is ISO C++17. Compilation should be trivial using any C++ compiler 
@@ -127,6 +130,18 @@ handled-specially-(see-[Epochs-in-Continuous-Time-Scales-aka-UTC](#epochs-in-con
 > [!CAUTION]
 > **Latest leap second considered in datetime library occured at: 2017/01/01**
 
+
+## For Developers
+
+Take a look at the [LLVM Coding Standards](https://llvm.org/docs/CodingStandards.html) 
+and if possible stick to it. 
+
+
+
+![alt text](images/dso_logo_m1.jpg "Title")
+
+
+
 ## Bibliography
 
 1. <a id="sofa_ts"></a> International Astronomical Union, Standards of Fundamental Astronomy, SOFA Time Scale and Calendar Tools, Document revision 1.63, 2023