diff --git a/@export/Environment.d.ts b/@export/Environment.d.ts
index 23079a8..6fd4e7c 100644
--- a/@export/Environment.d.ts
+++ b/@export/Environment.d.ts
@@ -5,9 +5,15 @@
 // ref=Darwinism.Env@Darwinism, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
 
 /**
+ * the IPC parallel environment
+ * 
 */
 declare namespace Environment {
    /**
+    * set the parallel batch threads
+    * 
+    * 
+     * @param n_threads -
    */
    function set_threads(n_threads: object): any;
 }
diff --git a/@export/Math.d.ts b/@export/Math.d.ts
index 8f19f9b..a6618ea 100644
--- a/@export/Math.d.ts
+++ b/@export/Math.d.ts
@@ -5,10 +5,18 @@
 // ref=Darwinism.Math@Darwinism, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
 
 /**
+ * math helpers
+ * 
 */
 declare namespace Math {
    /**
-     * @param env default value Is ``null``.
+    * measure the average distance for the given dataset
+    * 
+    * 
+     * @param x -
+     * @param env -
+     * 
+     * + default value Is ``null``.
    */
    function average_distance(x: any, env?: object): number;
 }
diff --git a/man/Darwinism/Environment/Environment.md b/man/Darwinism/Environment/Environment.md
index 491acb8..6c53c10 100644
--- a/man/Darwinism/Environment/Environment.md
+++ b/man/Darwinism/Environment/Environment.md
@@ -1,5 +1,5 @@
 # Environment
 
+the IPC parallel environment
 
-
-+ [set_threads](Environment/set_threads.1) 
++ [set_threads](Environment/set_threads.1) set the parallel batch threads
diff --git a/man/Darwinism/Environment/Environment/set_threads.1 b/man/Darwinism/Environment/Environment/set_threads.1
index 8eecb10..87425e3 100644
--- a/man/Darwinism/Environment/Environment/set_threads.1
+++ b/man/Darwinism/Environment/Environment/set_threads.1
@@ -1,9 +1,17 @@
 .\" man page create by R# package system.
 .TH ENVIRONMENT 1 2000-Jan "set_threads" "set_threads"
 .SH NAME
-set_threads \- 
+set_threads \- set the parallel batch threads
 .SH SYNOPSIS
 \fIset_threads(\fBn_threads\fR as integer);\fR
+.SH DESCRIPTION
+.PP
+set the parallel batch threads
+.PP
+.SH OPTIONS
+.PP
+\fBn_threads\fB \fR\- -. 
+.PP
 .SH SEE ALSO
 Environment
 .SH FILES
diff --git a/man/Darwinism/Math/Math.md b/man/Darwinism/Math/Math.md
index 15db337..1236708 100644
--- a/man/Darwinism/Math/Math.md
+++ b/man/Darwinism/Math/Math.md
@@ -1,5 +1,5 @@
 # Math
 
+math helpers
 
-
-+ [average_distance](Math/average_distance.1) 
++ [average_distance](Math/average_distance.1) measure the average distance for the given dataset
diff --git a/man/Darwinism/Math/Math/average_distance.1 b/man/Darwinism/Math/Math/average_distance.1
index a1c78ca..84781f6 100644
--- a/man/Darwinism/Math/Math/average_distance.1
+++ b/man/Darwinism/Math/Math/average_distance.1
@@ -1,10 +1,21 @@
 .\" man page create by R# package system.
 .TH MATH 1 2000-Jan "average_distance" "average_distance"
 .SH NAME
-average_distance \- 
+average_distance \- measure the average distance for the given dataset
 .SH SYNOPSIS
 \fIaverage_distance(\fBx\fR as any, 
 [\fB<Environment>\fR]);\fR
+.SH DESCRIPTION
+.PP
+measure the average distance for the given dataset
+.PP
+.SH OPTIONS
+.PP
+\fBx\fB \fR\- -. 
+.PP
+.PP
+\fBenv\fB \fR\- -. 
+.PP
 .SH SEE ALSO
 Math
 .SH FILES
diff --git a/vignettes/Darwinism/Environment.html b/vignettes/Darwinism/Environment.html
index dc9a5d1..5fca0e0 100644
--- a/vignettes/Darwinism/Environment.html
+++ b/vignettes/Darwinism/Environment.html
@@ -10,7 +10,7 @@
     <meta name="keywords" content="R#; Environment; Darwinism" />
     <meta name="generator" content="https://github.com/rsharp-lang" />
     <meta name="theme-color" content="#333" />
-    <meta name="description" content="..." />
+    <meta name="description" content="the IPC parallel environment..." />
     <meta class="foundation-data-attribute-namespace" />
     <meta class="foundation-mq-xxlarge" />
     <meta class="foundation-mq-xlarge" />
@@ -63,10 +63,10 @@ table caption {font-size:14px;font-weight:bolder;}
     <p style="     font-size: 1.125em;     line-height: .8em;     margin-left: 0.5%;     background-color: #fbfbfb;     padding: 24px; ">
       <code>
         <span style="color: blue;">require</span>(<span style="color: black; font-weight: bold;">Darwinism</span>);
-                               <br /><br /><span style="color: green;">{$desc_comments}</span><br /><span style="color: blue;">imports</span><span style="color: brown"> "Environment"</span><span style="color: blue;"> from</span><span style="color: brown"> "Darwinism"</span>;
+                               <br /><br /><span style="color: green;">#' the IPC parallel environment</span><br /><span style="color: blue;">imports</span><span style="color: brown"> "Environment"</span><span style="color: blue;"> from</span><span style="color: brown"> "Darwinism"</span>;
                            </code>
     </p>
-    <p></p>
+    <p><p>the IPC parallel environment</p></p>
     <blockquote>
       <p style="font-style: italic; font-size: 0.9em;">
                            
@@ -85,7 +85,7 @@ table caption {font-size:14px;font-weight:bolder;}
   <td id="set_threads">
     <a href="./Environment/set_threads.html">set_threads</a>
   </td>
-  <td></td>
+  <td><p>set the parallel batch threads</p></td>
 </tr></tbody>
       </table>
     </div>
diff --git a/vignettes/Darwinism/Environment/set_threads.html b/vignettes/Darwinism/Environment/set_threads.html
index f9ab73a..814e496 100644
--- a/vignettes/Darwinism/Environment/set_threads.html
+++ b/vignettes/Darwinism/Environment/set_threads.html
@@ -2,7 +2,7 @@
 <html>
 
 <head>
-    <title>set_threads</title>
+    <title>set the parallel batch threads</title>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes" />
     <link rel="stylesheet" type="text/css" href="../../_assets/page.css">
@@ -18,11 +18,11 @@
             </tr>
         </table>
 
-        <h2>set_threads</h2>
+        <h2>set the parallel batch threads</h2>
 
         <h3>Description</h3>
 
-        set_threads
+        
 
         <h3>Usage</h3>
 
@@ -34,6 +34,9 @@
 
         <table>
             
+<dt>n.threads</dt>
+<dd><p><p>-</p></p></dd>
+
         </table>
 
 
diff --git a/vignettes/Darwinism/Math.html b/vignettes/Darwinism/Math.html
index 90f8e32..409c906 100644
--- a/vignettes/Darwinism/Math.html
+++ b/vignettes/Darwinism/Math.html
@@ -10,7 +10,7 @@
     <meta name="keywords" content="R#; Math; Darwinism" />
     <meta name="generator" content="https://github.com/rsharp-lang" />
     <meta name="theme-color" content="#333" />
-    <meta name="description" content="..." />
+    <meta name="description" content="math helpers..." />
     <meta class="foundation-data-attribute-namespace" />
     <meta class="foundation-mq-xxlarge" />
     <meta class="foundation-mq-xlarge" />
@@ -63,10 +63,10 @@ table caption {font-size:14px;font-weight:bolder;}
     <p style="     font-size: 1.125em;     line-height: .8em;     margin-left: 0.5%;     background-color: #fbfbfb;     padding: 24px; ">
       <code>
         <span style="color: blue;">require</span>(<span style="color: black; font-weight: bold;">Darwinism</span>);
-                               <br /><br /><span style="color: green;">{$desc_comments}</span><br /><span style="color: blue;">imports</span><span style="color: brown"> "Math"</span><span style="color: blue;"> from</span><span style="color: brown"> "Darwinism"</span>;
+                               <br /><br /><span style="color: green;">#' math helpers</span><br /><span style="color: blue;">imports</span><span style="color: brown"> "Math"</span><span style="color: blue;"> from</span><span style="color: brown"> "Darwinism"</span>;
                            </code>
     </p>
-    <p></p>
+    <p><p>math helpers</p></p>
     <blockquote>
       <p style="font-style: italic; font-size: 0.9em;">
                            
@@ -90,7 +90,7 @@ table caption {font-size:14px;font-weight:bolder;}
   <td id="average_distance">
     <a href="./Math/average_distance.html">average_distance</a>
   </td>
-  <td></td>
+  <td><p>measure the average distance for the given dataset</p></td>
 </tr></tbody>
       </table>
     </div>
diff --git a/vignettes/Darwinism/Math/average_distance.html b/vignettes/Darwinism/Math/average_distance.html
index 7ab215e..e3191af 100644
--- a/vignettes/Darwinism/Math/average_distance.html
+++ b/vignettes/Darwinism/Math/average_distance.html
@@ -2,7 +2,7 @@
 <html>
 
 <head>
-    <title>average_distance</title>
+    <title>measure the average distance for the given dataset</title>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes" />
     <link rel="stylesheet" type="text/css" href="../../_assets/page.css">
@@ -18,11 +18,11 @@
             </tr>
         </table>
 
-        <h2>average_distance</h2>
+        <h2>measure the average distance for the given dataset</h2>
 
         <h3>Description</h3>
 
-        average_distance
+        
 
         <h3>Usage</h3>
 
@@ -34,6 +34,13 @@
 
         <table>
             
+<dt>x</dt>
+<dd><p><p>-</p></p></dd>
+
+
+<dt>env</dt>
+<dd><p><p>-</p></p></dd>
+
         </table>