OpenCL - float buffer values not the same in OpenCL and Java

[officialhopsof]

I create two float buffers like so

      int size = 1;
      inputBuffer = BufferUtils.createFloatBuffer(size);
      while (inputBuffer.position() < inputBuffer.capacity()) {
        inputBuffer.put(-1.0f);
      }
      inputBuffer.rewind();
      inputMemory = CL10.clCreateBuffer(clContext, CL10.CL_MEM_READ_WRITE, inputBuffer, clErrorBuffer);

      outputBuffer = BufferUtils.createFloatBuffer(size);
      outputBuffer.rewind();
      outputMemory = CL10.clCreateBuffer(clContext, CL10.CL_MEM_READ_WRITE, outputBuffer, clErrorBuffer);

then in my kernel I have

kernel void myKernel(global const float* input, global float* output){
  if(input[0] < 0.0f){
    output[0] = 1;
  } else {
    output[0] = 2;
  }
}

When I retrieve output[0] in java later it is always 2. Any idea why this is? I explicitly set the input buffer to be -1 for all values, and then in the kernel if input[0] is less than 0, which it should be, set output[0] to 1.

[Kai]

You are missing the CL_MEM_COPY_HOST_PTR flag for clCreateBuffer (or use clEnqueueWriteBuffer). See the documentation:
https://www.khronos.org/registry/OpenCL/sdk/1.0/docs/man/xhtml/clCreateBuffer.html
That should probably be it. However, it would still be interesting to see how you set the buffer argument to the kernel parameter.

[officialhopsof]

That did the trick! Thanks!

also

    clSetKernelArg1p(clKernel, 0, inputMemory);
    clSetKernelArg1p(clKernel, 1, outputMemory);