Document REFERENCE_CUTOFF_FAC; correct REFERENCE_CUTOFF default comments

ChangeLog

@@ -4,6 +4,14 @@
 -changes
 
 
+--------------
+October 29, 2026
+Name: Sayan Bhowmik
+Changes: doc/.LaTeX/Electrostatics.tex, doc/.LaTeX/Introduction.tex, doc/Manual.pdf, src/initialization.c
+1. Documented REFERENCE_CUTOFF_FAC (integer, default 0) in the manual. If > 0, REFERENCE_CUTOFF is set to
+   REFERENCE_CUTOFF_FAC * max(dx, dy, dz); this overrides REFERENCE_CUTOFF.
+2. Corrected the comments on the REFERENCE_CUTOFF and REFERENCE_CUTOFF_FAC defaults.
+
 --------------
 October 27, 2026
 Name: Sayan Bhowmik

doc/.LaTeX/Electrostatics.tex

@@ -141,7 +141,43 @@
 \end{block}
 
 \begin{block}{Remark}
-This number should be smaller than half the smallest interatomic distance.
+This number should be smaller than half the smallest interatomic distance. It is overridden by \hyperlink{REFERENCE_CUTOFF_FAC}{\texttt{REFERENCE\_CUTOFF\_FAC}} when the latter is greater than 0.
+\end{block}
+
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[allowframebreaks]{\texttt{REFERENCE\_CUTOFF\_FAC}} \label{REFERENCE_CUTOFF_FAC}
+\vspace*{-12pt}
+\begin{columns}
+\column{0.4\linewidth}
+\begin{block}{Type}
+Integer
+\end{block}
+
+\begin{block}{Default}
+0
+\end{block}
+
+\column{0.4\linewidth}
+\begin{block}{Unit}
+No unit
+\end{block}
+
+\begin{block}{Example}
+\texttt{REFERENCE\_CUTOFF\_FAC}: 2
+\end{block}
+\end{columns}
+
+\begin{block}{Description}
+If greater than 0, \hyperlink{REFERENCE_CUTOFF}{\texttt{REFERENCE\_CUTOFF}} is set to \texttt{REFERENCE\_CUTOFF\_FAC} $\times \max(\Delta x, \Delta y, \Delta z)$, where $\Delta x$, $\Delta y$, $\Delta z$ are the mesh spacings. The default 0 disables this option.
+\end{block}
+
+\begin{block}{Remark}
+Overrides \hyperlink{REFERENCE_CUTOFF}{\texttt{REFERENCE\_CUTOFF}} when greater than 0.
 \end{block}
 
 \end{frame}

doc/.LaTeX/Introduction.tex

@@ -346,7 +346,8 @@
   \hyperlink{TOL_POISSON}{\texttt{TOL\_POISSON}} $\vert$
   \hyperlink{MAXIT_POISSON}{\texttt{MAXIT\_POISSON}} $\vert$
   \hyperlink{TOL_PSEUDOCHARGE}{\texttt{TOL\_PSEUDOCHARGE}} $\vert$
-  \hyperlink{REFERENCE_CUTOFF}{\texttt{REFERENCE\_CUTOFF}} 
+  \hyperlink{REFERENCE_CUTOFF}{\texttt{REFERENCE\_CUTOFF}} $\vert$
+  \hyperlink{REFERENCE_CUTOFF_FAC}{\texttt{REFERENCE\_CUTOFF\_FAC}} 
   \end{block}
 
   \vspace{-2mm}

src/initialization.c

@@ -772,8 +772,8 @@ void set_defaults(SPARC_INPUT_OBJ *pSPARC_Input, SPARC_OBJ *pSPARC) {
     pSPARC_Input->precond_resta_q0 = 1.36;
     pSPARC_Input->precond_resta_Rs = 2.76;
 
-    pSPARC_Input->REFERENCE_CUTOFF = 0.5;     // default reference cutoff radius for nonlocal pseudopotential
-    pSPARC_Input->REFERENCE_CUTOFF_FAC = 0; // default reference cutoff radius relative to mesh size for nonlocal pseudopotential
+    pSPARC_Input->REFERENCE_CUTOFF = 0.5;     // default cutoff radius (Bohr) of the reference potential for the overlapping pseudocharge correction
+    pSPARC_Input->REFERENCE_CUTOFF_FAC = 0; // default: off; if > 0, REFERENCE_CUTOFF = REFERENCE_CUTOFF_FAC * max(dx, dy, dz)
 
     /* default mixing */
     pSPARC_Input->MixingVariable = -1;        // default mixing variabl (will be set to 'density' mixing)
@@ -4000,7 +4000,7 @@ void write_output_init(SPARC_OBJ *pSPARC) {
     }
 
     fprintf(output_fp,"***************************************************************************\n");
-    fprintf(output_fp,"*                     SPARC (version October 27, 2026)                     *\n");
+    fprintf(output_fp,"*                     SPARC (version October 29, 2026)                     *\n");
     fprintf(output_fp,"*   Copyright (c) 2020 Material Physics & Mechanics Group, Georgia Tech   *\n");
     fprintf(output_fp,"*           Distributed under GNU General Public License 3 (GPL)          *\n");
     fprintf(output_fp,"*                   Start time: %s                  *\n",c_time_str);