Add function signatures

CMakeLists.txt

@@ -112,7 +112,10 @@ endif()
 target_link_libraries(cint "-lm")
 
 install(TARGETS cint DESTINATION ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR})
-install(FILES ${PROJECT_BINARY_DIR}/include/cint.h DESTINATION ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR})
+set(CintHeaders
+ ${PROJECT_SOURCE_DIR}/include/cint_funcs.h
+ ${PROJECT_BINARY_DIR}/include/cint.h)
+install(FILES ${CintHeaders} DESTINATION ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR})
 
 if(ENABLE_EXAMPLE)
  enable_language(Fortran)

README

@@ -158,6 +158,21 @@ Installation
  make install
 
 
+Available Integrals
+-------------------
+
+The available integrals can be found in the header file cint_funcs.h. A simple
+expression for each integral is also listed in the header file. The integral
+function names and integral expressions correspond to the lisp symbol notations
+in scripts/auto_intor.cl
+
+All integral functions have the same function signature
+
+```
+function_name(double *out, int *dims, int *shls, int *atm, int natm, int *bas, int nbas, double *env, CINTOpt *opt, double *cache);
+```
+
+
 Known problems
 --------------
 

doc/program_ref.tex

@@ -225,6 +225,26 @@ \subsection{C routine}\label{c-routine}
 CINTdel_optimizer(&opt);
 \end{verbatim}
 
+In libcint-3 or above, new integral function signature are provided.
+\begin{verbatim}
+int1e_xxx(buf, dims, shls, atm, natm, bas, nbas, env, opt, cache);
+int2e_xxx(buf, dims, shls, atm, natm, bas, nbas, env, opt, cache);
+\end{verbatim}
+In the new
+function signature, the shape of output buffer (in column-major order) can be
+specified. It's the second argument \verb$dims$. Integrals can be written
+to the sub-block or the output buffer according to the information of
+\verb$dims$. Another change is the runtime \verb$cache$ for integral
+intermediates, which comes as the last arguments of the new signature. If
+\verb$cache$ is specified, all integral intermediates will be put in the
+\verb$cache$. The library will not use extra main memory during computatin. The
+size of cache can be determined by the function if the first argument is set to
+\verb$NULL$
+\begin{verbatim}
+int cache_size = int1e_xxx(NULL, dims, shls, atm, natm, bas, nbas, env, opt, NULL);
+\end{verbatim}
+
+
 \subsection{Fortran routine}\label{fortran-routine}
 
 \begin{verbatim}

include/cint.h.in

@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2013- Qiming Sun <[email protected]>
  *
- * Parameters and function prototypes for libcint.
+ * Parameters and function signature for libcint.
  */
 
 #define CINT_VERSION @cint_VERSION@