1 files changed, 65 insertions, 0 deletions
diff --git a/help/en_US/ifht.xml b/help/en_US/ifht.xml
new file mode 100644
index 0000000..e4e692b
--- /dev/null
+++ b/help/en_US/ifht.xml
@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+ *
+ * This help file was generated from ifht.sci using help_from_sci().
+ *
+ -->
+
+<refentry version="5.0-subset Scilab" xml:id="ifht" xml:lang="en"
+          xmlns="http://docbook.org/ns/docbook"
+          xmlns:xlink="http://www.w3.org/1999/xlink"
+          xmlns:svg="http://www.w3.org/2000/svg"
+          xmlns:ns3="http://www.w3.org/1999/xhtml"
+          xmlns:mml="http://www.w3.org/1998/Math/MathML"
+          xmlns:scilab="http://www.scilab.org"
+          xmlns:db="http://docbook.org/ns/docbook">
+
+  <refnamediv>
+    <refname>ifht</refname>
+    <refpurpose>Calculate the inverse Fast Hartley Transform of real input D</refpurpose>
+  </refnamediv>
+
+
+<refsynopsisdiv>
+   <title>Calling Sequence</title>
+   <synopsis>
+   m= ifht (d)
+   m= ifht (d,n)
+   m= ifht (d,n,dim)
+   </synopsis>
+</refsynopsisdiv>
+
+<refsection>
+   <title>Parameters</title>
+   <variablelist>
+   <varlistentry><term>d:</term>
+      <listitem><para> real or complex valued scalar or vector</para></listitem></varlistentry>
+   <varlistentry><term>n:</term>
+      <listitem><para> Similar to the options of FFT function</para></listitem></varlistentry>
+   <varlistentry><term>dim:</term>
+      <listitem><para> Similar to the options of FFT function</para></listitem></varlistentry>
+   </variablelist>
+</refsection>
+
+<refsection>
+   <title>Description</title>
+   <para>
+Calculate the inverse Fast Hartley Transform of real input d. If d is a matrix, the inverse Hartley transform is calculated along the columns by default. The options n and dim are similar to the options of FFT function.
+   </para>
+   <para>
+The forward and inverse Hartley transforms are the same (except for a scale factor of 1/N for the inverse hartley transform), but implemented using different functions.
+   </para>
+   <para>
+The definition of the forward hartley transform for vector d, m[K] = 1/N \sum_{i=0}^{N-1} d[i]*(cos[K*2*pi*i/N] + sin[K*2*pi*i/N]), for 0 &lt;= K &lt; N. m[K] = 1/N \sum_{i=0}^{N-1} d[i]*CAS[K*i], for 0 &lt;= K &lt; N.
+</para>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+ifht(1 : 4)
+ifht(1:4, 2)
+   ]]></programlisting>
+</refsection>
+</refentry>