sdk/1.2/docs/man/shuffle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
              "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">

<refentry>
    <refentryinfo>
        <keywordset>
            <keyword>shuffle, shuffle2</keyword>
        </keywordset>
    </refentryinfo>

    <refmeta>
        <refentrytitle>shuffle, shuffle2</refentrytitle>

        <refmiscinfo>
            <copyright>
                <year>2007-2011</year>
                <holder>The Khronos Group Inc.
 Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials.</holder>
            </copyright>
        </refmiscinfo>
        <manvolnum>3</manvolnum>
    </refmeta>

<!-- ================================ SYNOPSIS -->

    <refnamediv id="shuffle">
        <refname>shuffle</refname>

        <refpurpose>
            Constructs a permutation of elements from one (or two) input vectors.
        </refpurpose>
    </refnamediv>

    <refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>
                    gentype<replaceable>n</replaceable>
                    <function>
                        shuffle
                    </function>
                </funcdef>
                <paramdef>gentype<replaceable>m</replaceable><parameter>x</parameter></paramdef>
                <paramdef>ugentype<replaceable>n</replaceable><parameter>mask</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>

        <funcsynopsis>
            <funcprototype>
                <funcdef>
                    gentype<replaceable>n</replaceable>
                    <function>
                        shuffle2
                    </function>
                </funcdef>
                <paramdef>gentype<replaceable>m</replaceable><parameter>x</parameter></paramdef>
                <paramdef>gentype<replaceable>m</replaceable><parameter>y</parameter></paramdef>
                <paramdef>ugentype<replaceable>n</replaceable><parameter>mask</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>

<!-- ================================ DESCRIPTION  -->

    <refsect1 id="description"><title>Description</title>
        <para>
          The <function>shuffle</function> and <function>shuffle2</function>
          built-in functions construct a permutation of elements from one or two input
          vectors respectively that are of the same type, returning a vector with the
          same element type as the input and length that is the same as the shuffle
          mask. The size of each element in the <varname>mask</varname> must match the
          size of each element in the result. For <function>shuffle</function>, only the
          <citerefentry><refentrytitle>ilogb</refentrytitle></citerefentry>(2<replaceable>m</replaceable>-1)
          least significant bits of each <varname>mask</varname>
          element are considered. For <function>shuffle2</function>, only the
          <citerefentry><refentrytitle>ilogb</refentrytitle></citerefentry>(2<replaceable>m</replaceable>-1)+1
          least significant bits of each <varname>mask</varname> element are considered. Other
          bits in the <varname>mask</varname> shall be ignored.
        </para>

        <para>
          The elements of the input vectors are numbered from left to right across one or
          both of the vectors.  For this purpose, the number of elements in a vector is given by
          <citerefentry><refentrytitle>vec_step</refentrytitle></citerefentry>(gentype<replaceable>m</replaceable>).
          The shuffle <varname>mask</varname> operand specifies, for each element of the result
          vector, which element of the one or two input vectors the result element gets.
        </para>

        <para>
          We use the generic type name <type>gentype<replaceable>n</replaceable></type>
          (or <type>gentype<replaceable>m</replaceable></type>) to indicate the
          built-in data types <type>char{2|4|8|16}</type>, <type>uchar{2|4|8|16}</type>,
          <type>short{2|4|8|16}</type>, <type>ushort{2|4|8|16}</type>, <type>int{2|4|8|16}</type>,
          <type>uint{2|4|8|16}</type>, <type>long{2|4|8|16}</type>, <type>ulong{2|4|8|16}</type>,
          or <type>float{2|4|8|16}</type> as the type for the arguments unless otherwise
          stated. We use the generic name <type>ugentype<replaceable>n</replaceable></type>
          to indicate the built-in unsigned integer data types. If the <type>double</type>
          is supported, then <type>gentype<replaceable>n</replaceable></type> (or
          <type>gentype<replaceable>m</replaceable></type>) also indicate the built-in data
          types <type>double{2|4|8|16}</type>.
        </para>

        <para>
          The generic type name <type>gentype<replaceable>n</replaceable></type>
          (or <type>gentype<replaceable>m</replaceable></type>)
          may indicate the data type <type>half{2|4|8|16}</type> if the
          <citerefentry><refentrytitle>cl_khr_fp16</refentrytitle></citerefentry> extension
          is supported.
        </para>
    </refsect1>

<!-- ================================ NOTES

    <refsect1 id="notes"><title>Notes</title>


    </refsect1>-->

<!-- ================================ EXAMPLE  -->

    <refsect2 id="example1">
        <title>
            Example
        </title>

        <informaltable frame="none">
            <tgroup cols="1" align="left" colsep="0" rowsep="0">
                <colspec colname="col1" colnum="1" />
                <tbody>
                    <row>
                        <entry>
uint4 mask = (uint4)(3, 2, 1, 0);
float4 a;
float4 r = shuffle(a, mask);
// r.s0123 = a.wzyx

uint8 mask = (uint8)(0, 1, 2, 3, 4, 5, 6, 7);

float4 a, b;
float8 r = shuffle2(a, b, mask);
// r.s0123 = a.xyzw
// r.s4567 = b.xyzw

uint4 mask;
float8 a;
float4 b;
b = shuffle(a, mask);

                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>

        <para>
          Examples that are not valid are:
        </para>

        <informaltable frame="none">
            <tgroup cols="1" align="left" colsep="0" rowsep="0">
                <colspec colname="col1" colnum="1" />
                <tbody>
                    <row>
                        <entry>
uint8 mask;
short16 a;
short8 b;
b = shuffle(a, mask);

                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect2>

<!-- ================================ SPECIFICATION  -->
<!-- Set the "uri" attribute in the <olink /> element to the "named destination" for the PDF page
-->
    <refsect1 id="specification"><title>Specification</title>
        <para>
            <imageobject>
                <imagedata fileref="pdficon_small1.gif" format="gif" />
            </imageobject>

            <olink uri="miscVectorFunctions">OpenCL Specification</olink>
        </para>
    </refsect1>

<!-- ================================ ALSO SEE  -->

    <refsect1 id="seealso"><title>Also see</title>
        <para>
            <citerefentry href="miscVectorFunctions"><refentrytitle>Miscellaneous Vector Functions</refentrytitle></citerefentry>
        </para>
    </refsect1>

<!-- ============================== COPYRIGHT -->
<!-- Content included from copyright.inc.xsl -->

    <refsect3 id="Copyright"><title></title>
        <imageobject>
                <imagedata fileref="KhronosLogo.jpg" format="jpg" />
        </imageobject>
        <para />
    </refsect3>

<!-- 13-Oct-2011 -->
</refentry>