From 282dcd3c58ab0df7c8d0655b1e6142eaa1562d9a Mon Sep 17 00:00:00 2001
From: Alex Selimov <aselimov3@gatech.edu>
Date: Tue, 28 Jan 2020 11:35:14 -0500
Subject: [PATCH 1/2] Add random position

---
 src/main.f90        | 2 ++
 src/subroutines.f90 | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/src/main.f90 b/src/main.f90
index ed34c53..a608f19 100644
--- a/src/main.f90
+++ b/src/main.f90
@@ -23,6 +23,8 @@ program main
     !Call initialization functions
     call lattice_init
     call box_init
+    call random_seed
+    
     end_mode_arg = 0
     
     ! Command line parsing
diff --git a/src/subroutines.f90 b/src/subroutines.f90
index 9fd159c..f7a22ad 100644
--- a/src/subroutines.f90
+++ b/src/subroutines.f90
@@ -178,6 +178,7 @@ module subroutines
         real(kind=dp), intent(out) :: pos !The output parsed position value
 
         integer :: iospara
+        real(kind=dp) :: rand
 
         iospara = 0
         if(trim(adjustl(pos_string)) == 'inf') then 
@@ -208,6 +209,10 @@ module subroutines
                 read(pos_string(1:index(pos_string,'*')-1), *, iostat=iospara) pos
             end if
             pos = (box_bd(2*i)-box_bd(2*i-1))*pos + box_bd(2*i-1)
+
+        else if (trim(adjustl(pos_string)) == 'rand') then 
+            call random_number(rand)
+            pos = (box_bd(2*i)-box_bd(2*i-1))*rand + box_bd(2*i-1)
         else
             read(pos_string, *, iostat=iospara) pos
         end if

From 64926a4e16ae447f8352edc61ba23ca9fe7cb544 Mon Sep 17 00:00:00 2001
From: Alex <aselimov3@gatech.edu>
Date: Wed, 29 Jan 2020 09:30:51 -0500
Subject: [PATCH 2/2] Update to documentation for position specifiers

---
 README.md | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 5d45ef3..821ccc5 100644
--- a/README.md
+++ b/README.md
@@ -225,4 +225,23 @@ This command remeshes the atoms/elements within the group to the new element siz
 -ow
 ```
 
-If this option is passed then all files are automatically overwritten without asking the user.
\ No newline at end of file
+If this option is passed then all files are automatically overwritten without asking the user.
+
+## Position Specification
+
+Specifying positions in cacmb can be done through a variety of ways. Examples of each format is shown below.
+
+`val` - Where `val` is a number, then that value in Angstroms is used as the position. As an example, `11.1` would be read in as a position of 11.1 $\AA$.
+
+`-inf` - This specifies the lower box boundary in the specific dimension. The vector `-inf -inf -inf`  specifies the bottom corner of the simulation cell which also acts as the simulation cell origin. The vector `-inf 10 3` instead puts only the x position at the simulation cell origin.
+
+`inf` - Similar to `-inf` but references the upper boundary of the box in that dimension
+
+`inf-val` - Using a minus sign reduces the position from the **upper boundary** by `val`. `inf-10` would be at a distance of $10 \AA$ from the upper boundary in that dimension.
+
+`inf+val` - This increases the position from the **lower boundary**. `inf+10` would be a position $10\AA$ from the lower boundary within the cell.
+
+`inf*val` - This gives you a fractional position in the simulation cell. As an example `inf*0.5` gives you the center point of the simulation cell. 
+
+`rand` - Returns a random position that lies within the simulation cell.
+