definitions/simd-loop/loop_106.json

{
  "name": "loop_106",
  "op_type": "loop_106",
  "description": "Partition a vector by bit flag, concentrating set-bit elements to one side",
  "tags": [
    "simd-loop"
  ],
  "axes": {
    "n": {
      "type": "var",
      "description": "axis n"
    }
  },
  "inputs": {
    "a": {
      "shape": [
        "n"
      ],
      "dtype": "uint32"
    }
  },
  "outputs": {
    "b": {
      "shape": [
        "n"
      ],
      "dtype": "uint32",
      "description": "Output array"
    }
  },
  "reference": "import numpy as np\n\n_M = 0xFFFFFFFF\n\ndef _popcount(x):\n    return bin(x & _M).count('1')\n\ndef _compress(x, m):\n    x &= m\n    mk = (~m << 1) & _M\n    for i in range(5):\n        mp = (mk ^ (mk << 1)) & _M\n        mp = (mp ^ (mp << 2)) & _M\n        mp = (mp ^ (mp << 4)) & _M\n        mp = (mp ^ (mp << 8)) & _M\n        mp = (mp ^ (mp << 16)) & _M\n        mv = mp & m\n        m = (m ^ mv) | (mv >> (1 << i))\n        t = x & mv\n        x = (x ^ t) | (t >> (1 << i))\n        mk &= (~mp) & _M\n    return x & _M\n\ndef _sag(x, m):\n    return (((_compress(x, m) << _popcount(m)) & _M) | _compress(x, (~m) & _M)) & _M\n\n_PC = [0xaaaaaaaa, 0xcccccccc, 0x0f0f0f0f, 0x0ff00ff0, 0x0ffff000]\n_P = [_PC[0], _sag(_PC[1], _PC[0]), _sag(_PC[2], _PC[0]),\n      _sag(_PC[3], _PC[0]), _sag(_PC[4], _PC[0])]\n\ndef _permute(x):\n    for pi in _P:\n        x = _sag(x, pi)\n    return x\n\ndef run(a):\n    return np.array([_permute(int(v)) for v in a], dtype=np.uint32)\n",
  "simd_loop_meta": {
    "output_inplace": false,
    "array_pad": 0,
    "scratch": [],
    "axes_order": [
      "n"
    ]
  }
}