sdk/1.1/docs/man/shuffle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
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<refentry>
    <refentryinfo>
        <keywordset>
            <keyword>shuffle, shuffle2</keyword>
        </keywordset>
    </refentryinfo>

    <refmeta>                                    
        <refentrytitle>shuffle</refentrytitle>

        <refmiscinfo>
            <copyright>
                <year>2007-2010</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.
        </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, and may 
            indicate the data type <type>double{2|4|8|16}</type> if 
            the <citerefentry><refentrytitle>cl_khr_fp64</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>

</refentry>