如何运行Apple的OpenCL"Hello World" XCode中的示例 [英] How to run Apple's OpenCL "Hello World" example in XCode

问题描述

Apple提供了一个OpenCL"Hello World"示例，可以从以下页面将其作为.zip文件下载:

Apple provides an OpenCL "Hello World" example, which can be downloaded as a .zip file from the following page:

https://developer.apple.com/library/mac/samplecode/OpenCL_Hello_World_Example/Introduction/Intro.html

我下载了它，在Xcode中打开了项目，然后单击了Run.构建成功，但是出现以下错误消息: Error: Failed to create a device group!

I downloaded it, opened the project in Xcode, and clicked Run. The build succeeded, but I got the following error message: Error: Failed to create a device group!

对于在Mac上运行一个简单的OpenCL示例的任何建议，我将不胜感激.如果它在诊断上是相关的:我在2011年初的MacBook Pro上运行Mac OS 10.7.5，并且安装了Xcode 4.2.

I would appreciate any advice on how to get a simple OpenCL example running on my Mac. In case it is diagnostically relevant: I'm running Mac OS 10.7.5 on an early 2011 MacBook Pro, and I have Xcode version 4.2 installed.

推荐答案

万岁，我自己解决了这个问题. Apple提供的hello.c文件包含以下代码行:

Hooray, I worked it out myself. The hello.c file that Apple provides contains the following lines of code:

114    // Connect to a compute device
115    //
116    int gpu = 1;
117    err = clGetDeviceIDs(NULL, gpu ? CL_DEVICE_TYPE_GPU : CL_DEVICE_TYPE_CPU, 1, &device_id, NULL);
118    if (err != CL_SUCCESS)
119    {
120        printf("Error: Failed to create a device group!\n");
121        return EXIT_FAILURE;
122    }

代码正在尝试获取支持OpenCL的GPU设备的ID.问题是我的机器(MacBook Pro，2011年初)没有支持OpenCL的GPU.如果改为设置CL_DEVICE_TYPE_CPU标志，则找到CPU，并且此确实支持OpenCL.如果文件修改如下:

The code is trying to get the id of a GPU device that supports OpenCL. The problem is that my machine (MacBook Pro, Early 2011) doesn't have a GPU that supports OpenCL. If the CL_DEVICE_TYPE_CPU flag is set instead, then the CPU is found, and this does support OpenCL. If the file is modified as follows:

116    int gpu = 0;

然后我得到输出: Computed '1024/1024' correct values!

then I get the output: Computed '1024/1024' correct values!

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