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/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtOpenCL module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qclworksize.h"
#include "qcldevice.h"
QT_BEGIN_NAMESPACE
/*!
\class QCLWorkSize
\brief The QCLWorkSize class defines the size of an item of work for an OpenCL kernel.
\since 4.7
\ingroup opencl
OpenCL work sizes may be single-dimensional, two-dimensional,
or three-dimensional:
\code
QCLWorkSize oned(128);
QCLWorkSize twod(16, 16);
QCLWorkSize threed(32, 32, 16);
...
QCLKernel kernel = ...;
kernel.setGlobalWorkSize(oned);
kernel.setGlobalWorkSize(twod);
kernel.setGlobalWorkSize(threed);
\endcode
For convenience, QCLKernel::setGlobalWorkSize() and
QCLKernel::setLocalWorkSize() can be specified by a QCLWorkSize
object or direct numeric arguments:
\code
QCLKernel kernel = ...;
kernel.setGlobalWorkSize(128);
kernel.setGlobalWorkSize(16, 16);
kernel.setGlobalWorkSize(32, 32, 16);
\endcode
\sa QCLKernel
*/
/*!
\fn QCLWorkSize::QCLWorkSize()
Constructs a default work size consisting of a single dimension
with width() set to 1.
*/
/*!
\fn QCLWorkSize::QCLWorkSize(size_t size)
Constructs a single-dimensional work size with width() set to \a size.
The height() and depth() will be set to 1.
*/
/*!
\fn QCLWorkSize::QCLWorkSize(size_t width, size_t height)
Constructs a two-dimensional work size of \a width x \a height.
The depth() will be set to 1.
*/
/*!
\fn QCLWorkSize::QCLWorkSize(const QSize &size)
Constructs a two-dimensional work size set to \a size.
The depth() will be set to 1.
*/
/*!
\fn QCLWorkSize::QCLWorkSize(size_t width, size_t height, size_t depth)
Constructs a three-dimensional work size of \a width x \a height x
\a depth.
*/
/*!
\fn size_t QCLWorkSize::dimensions() const
Returns the number of dimensions for this work size, 1, 2, or 3.
*/
/*!
\fn size_t QCLWorkSize::width() const
Returns the width of this work size specification.
*/
/*!
\fn size_t QCLWorkSize::height() const
Returns the height of this work size specification.
*/
/*!
\fn size_t QCLWorkSize::depth() const
Returns the depth of this work size specification.
*/
/*!
\fn const size_t *QCLWorkSize::sizes() const
Returns a const pointer to the size array within this object.
*/
/*!
\fn bool QCLWorkSize::operator==(const QCLWorkSize &other) const
Returns true if this work size specification has the same
dimensions as \a other; false otherwise.
\sa operator!=()
*/
/*!
\fn bool QCLWorkSize::operator!=(const QCLWorkSize &other) const
Returns true if this work size specification does not have
the same dimensions as \a other; false otherwise.
\sa operator==()
*/
static size_t qt_gcd_of_size(size_t x, size_t y)
{
size_t remainder;
while ((remainder = x % y) != 0) {
x = y;
y = remainder;
}
return y;
}
/*!
Returns the best-fit local work size that evenly divides this work
size and fits within the maximums defined by \a maxWorkItemSize
and \a maxItemsPerGroup.
This function is typically used to convert an arbitrary global
work size on a QCLKernel into a compatible local work size.
\sa QCLKernel::setLocalWorkSize()
*/
QCLWorkSize QCLWorkSize::toLocalWorkSize
(const QCLWorkSize &maxWorkItemSize, size_t maxItemsPerGroup) const
{
// Adjust for the maximum work item size in each dimension.
size_t width = m_dim >= 1 ? qt_gcd_of_size(m_sizes[0], maxWorkItemSize.width()) : 1;
size_t height = m_dim >= 2 ? qt_gcd_of_size(m_sizes[1], maxWorkItemSize.height()) : 1;
size_t depth = m_dim >= 3 ? qt_gcd_of_size(m_sizes[2], maxWorkItemSize.depth()) : 1;
// Reduce in size by a factor of 2 until underneath the maximum group size.
while (maxItemsPerGroup && (width * height * depth) > maxItemsPerGroup) {
width = (width > 1) ? (width / 2) : 1;
height = (height > 1) ? (height / 2) : 1;
depth = (depth > 1) ? (depth / 2) : 1;
}
// Return the final result.
if (m_dim >= 3)
return QCLWorkSize(width, height, depth);
else if (m_dim >= 2)
return QCLWorkSize(width, height);
else
return QCLWorkSize(width);
}
/*!
Returns the best-fit local work size that evenly divides this
work size and fits within the maximum work group size of \a device.
This function is typically used to convert an arbitrary global
work size on a QCLKernel into a compatible local work size.
\sa QCLKernel::setLocalWorkSize()
*/
QCLWorkSize QCLWorkSize::toLocalWorkSize(const QCLDevice &device) const
{
return toLocalWorkSize(device.maximumWorkItemSize(),
device.maximumWorkItemsPerGroup());
}
QT_END_NAMESPACE
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