numpy, pytorch, vscode self-test questions

1. For a given array, to take a specific value, the other is set to 0, such pytorch segmentation results contain a plurality of classes, taking only a particular class, do?

#classp = [0,1,2,2,3,0,5,2]这样，后面box,score,mask与之对应
ids = torch.where(classp==0)#选择人类别
classp = classp[ids]
box = box[ids]
score = score[ids]
mask = mask[ids[0], :]

  Similar can be simpler

#classp = [0,1,2,2,3,0,5,2]这样，后面box,score,mask与之对应
ids = (classp==0)#选择人类别
classp = classp[ids]
box = box[ids]
score = score[ids]
mask = mask[ids, :]

  

2. pytorch the inference stage, how to ensure that the model is no gradient information?

  Use with torch.no_grad (), modified

with torch.no_grad():
            cudnn.fastest = True
            torch.set_default_tensor_type('torch.cuda.FloatTensor')
            print('yolact loading model...', end='')
            net = Yolact()
            net.load_weights(config.yolact['model_path'])
            net.eval()
            print(' Done.')
            self.net = net.cuda()
            self.net.detect.use_fast_nms = True
            self.net.detect.use_cross_class_nms = False

3. How to numpy array into pytorch tensor, in conversion to the cuda

  torch.from_numpy(np_array).cuda().float()

How 4.vs code debugging inside a file? How to join the tuning parameters, many args? How to use python conda environment? How to specify debug working directory?

  1) through a graphical interface operation, generating launch.json

  2) Editing added args: [ "- thresh = 0.5", "--cuda"

  3)加入pythonPath:"/home/silva/anaconda3/envs/py372/bin/python"

 4）加入cwd:"/home/silva/work"

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        
        {
            "name": "Python: Current File",
            "type": "python",
            "request": "launch",
            "program": "${file}",
            "pythonPath": "/home/silva/anaconda3/envs/py372/bin/python",
            "cwd": "${fileDirname}",
            "args": [
                "--trained_model=weights/yolact_resnet50_54_800000.pth",
                "--score_threshold=0.15",
                "--top_k=15",
                "--video_multiframe=4",
                "--video=0"
            ]
        }
    ]
}

5. numpy array passed as parameters are passed by reference, or a copy transfer?

  Had often wrong, the original is passed by reference. Inside the function, modify the array, then calls the function of the array will be modified.

  def abc(arr): arr = np.zeros((3,3))

  Call a = np.ones ((3,3)), then the abc (a), after the execution, print (a) How much? constant

  If def abc (arr): arr + = 3, abc (a) after the execution? An increase of 3

If def abc (arr): arr [1] [1] = 34, abc (a) after performing? a corresponding element 34 becomes

Reference  https://stackoverflow.com/questions/11585793/are-numpy-arrays-passed-by-reference