RuntimeError: Ninja is required to load C++ extensions

run code by python tools/eval.py -n yolox-s -c yolox_s.pth -b 2 -d 1 --conf 0.001

error:
2022-07-30 00:16:44.546 | ERROR | yolox.core.launch:launch:98 - An error has been caught in function 'launch', process 'MainProcess' (73156), thread 'MainThread' (85696):
Traceback (most recent call last):

File "tools/eval.py", line 219, in
args=(exp, args, num_gpu),
│ │ └ 1
│ └ Namespace(batch_size=2, ckpt='yolox_s.pth', conf=0.001, devices=1, dist_backend='nccl', dist_url=None, exp_file=None, experim...
└ ╒═══════════════════╤════════════════════════════════════════════════════════════════════════════════════════════════════════...

File "d:\pywork\3.debug\yolox\yolox\core\launch.py", line 98, in launch
main_func(*args)
│ └ (╒═══════════════════╤═══════════════════════════════════════════════════════════════════════════════════════════════════════...
└ <function main at 0x0000023B5407F730>

File "tools/eval.py", line 194, in main
model, is_distributed, args.fp16, trt_file, decoder, exp.test_size
│ │ │ │ │ │ │ └ (640, 640)
│ │ │ │ │ │ └ ╒═══════════════════╤════════════════════════════════════════════════════════════════════════════════════════════════════════...
│ │ │ │ │ └ None
│ │ │ │ └ None
│ │ │ └ False
│ │ └ Namespace(batch_size=2, ckpt='yolox_s.pth', conf=0.001, devices=1, dist_backend='nccl', dist_url=None, exp_file=None, experim...
│ └ False
└ YOLOX(
(backbone): YOLOPAFPN(
(backbone): CSPDarknet(
(stem): Focus(
(conv): BaseConv(
(conv): ...

File "d:\pywork\3.debug\yolox\yolox\evaluators\coco_evaluator.py", line 242, in evaluate
eval_results = self.evaluate_prediction(data_list, statistics)
│ │ │ └ tensor([2.1702, 0.0110, 4.0000], device='cuda:0')
│ │ └ [{'image_id': 0, 'category_id': 56, 'bbox': [-33.6690673828125, 9.699737548828125, 3907.0078125, 2132.7041015625], 'score': 0...
│ └ <function COCOEvaluator.evaluate_prediction at 0x0000023B58CC9BF8>
└ <yolox.evaluators.coco_evaluator.COCOEvaluator object at 0x0000023B60FC6F28>

File "d:\pywork\3.debug\yolox\yolox\evaluators\coco_evaluator.py", line 317, in evaluate_prediction
from yolox.layers import COCOeval_opt as COCOeval

File "d:\pywork\3.debug\yolox\yolox\layers_init_.py", line 11, in
from .fast_coco_eval_api import COCOeval_opt

File "d:\pywork\3.debug\yolox\yolox\layers\fast_coco_eval_api.py", line 17, in
FastCOCOEvalOp().jit_load()
└ <class 'yolox.layers.jit_ops.FastCOCOEvalOp'>

File "d:\pywork\3.debug\yolox\yolox\layers\jit_ops.py", line 107, in jit_load
verbose=verbose,
└ True

File "D:\F\Anaconda3\envs\yolox\lib\site-packages\torch\utils\cpp_extension.py", line 1136, in load
keep_intermediates=keep_intermediates)
└ True

File "D:\F\Anaconda3\envs\yolox\lib\site-packages\torch\utils\cpp_extension.py", line 1347, in _jit_compile
is_standalone=is_standalone)
└ False

File "D:\F\Anaconda3\envs\yolox\lib\site-packages\torch\utils\cpp_extension.py", line 1418, in _write_ninja_file_and_build_library
verify_ninja_availability()
└ <function verify_ninja_availability at 0x0000023B632F7268>

File "D:\F\Anaconda3\envs\yolox\lib\site-packages\torch\utils\cpp_extension.py", line 1474, in verify_ninja_availability
raise RuntimeError("Ninja is required to load C++ extensions")

RuntimeError: Ninja is required to load C++ extensions
How can I solve this on a windows machine ?

When i use pip install ninja, it shows Requirement already satisfied: ninja in d:\f\anaconda3\envs\yolox\lib\site-packages (1.10.2.3)

Start with tools/eval.py and trace the failure into yolox/layers/fast_coco_eval_api.py and yolox/layers/jit_ops.py, especially FastCOCOEvalOp.jit_load(). Re-run the reported evaluation command on Windows and verify that the C++ extension loads successfully without the Ninja RuntimeError.