Pytorch executeable works while running from Anaconda prompt but not from Cmd or .exe?
I packaged (using Pyinstaller) a small variant of the Minimalistic Yolo github repo, found Here, the packaging was done using pyinstaller to run the object detection as a server using Flask.
So while attempting to run the server, it only works when running from Anaconda Prompt (Which is where i wrote the pyinstaller command) other than that, the following error occur.
Error i Get while running from (exe,Cmd,PowerShell) is:
Traceback (most recent call last):
File &quot;flask\app.py&quot;, line 2446, in wsgi_app
File &quot;flask\app.py&quot;, line 1951, in full_dispatch_request
File &quot;flask\app.py&quot;, line 1820, in handle_user_exception
File &quot;flask\_compat.py&quot;, line 39, in reraise
File &quot;flask\app.py&quot;, line 1949, in full_dispatch_request
File &quot;flask\app.py&quot;, line 1935, in dispatch_request
File &quot;FlaskServerV2.py&quot;, line 53, in Hello
File &quot;torch\nn\modules\module.py&quot;, line 532, in __call__
File &quot;models.py&quot;, line 259, in forward
File &quot;torch\nn\modules\module.py&quot;, line 532, in __call__
File &quot;models.py&quot;, line 177, in forward
RuntimeError: error in LoadLibraryA
127.0.0.1 - - [19/Nov/2020 10:28:53] &quot;GET /detect HTTP/1.1&quot; 500 -

But when running in conda, the code works fine and runs.
so I am suspecting it's an issue with a PyTorch dependency.
Current Code:
from __future__ import division

from flask import Flask, Response, jsonify
app = Flask(__name__)

from models import *
from utils.utils import *
from utils.datasets import *

import os
import sys
import time
import datetime
import argparse

from PIL import Image

import torch
from torch.utils.data import DataLoader
from torchvision import datasets
from torch.autograd import Variable

import matplotlib.pyplot as plt
import matplotlib.patches as patches
from matplotlib.ticker import NullLocator

import cv2 
import time 
import json


@app.route('/CheckIfRunning')
def CheckIfRunning():
    return '1'

@app.route('/detect')
def Hello():
    global device
    global model
    global classes
    global colors
    global Tensor
    global a
    img=cv2.imread(&quot;temp.jpg&quot;)
    PILimg = np.array(Image.fromarray(cv2.cvtColor(img,cv2.COLOR_BGR2RGB)))
    imgTensor = transforms.ToTensor()(PILimg)
    imgTensor, _ = pad_to_square(imgTensor, 0)
    imgTensor = resize(imgTensor, 416)
    #add the batch size
    imgTensor = imgTensor.unsqueeze(0)
    imgTensor = Variable(imgTensor.type(Tensor))
    with torch.no_grad():
        detections = model(imgTensor)
        detections = non_max_suppression(detections,0.8, 0.4)
    a.clear()

    Return={}
    ReturnCounter=0
    if detections is not None:
            a.extend(detections)
            b=len(a)
            if len(a)  :
                for detections in a:
                    if detections is not None:
                        detections = rescale_boxes(detections, 416, PILimg.shape[:2])
                        unique_labels = detections[:, -1].cpu().unique()
                        n_cls_preds = len(unique_labels)
                        for x1, y1, x2, y2, conf, cls_conf, cls_pred in detections:
                            box_w = x2 - x1
                            box_h = y2 - y1
                            color = [int(c) for c in colors[int(cls_pred)]]
                            img = cv2.rectangle(img, (x1, y1 + box_h), (x2, y1), color, 2)
                            cv2.putText(img, classes[int(cls_pred)], (x1, y1),     cv2.FONT_HERSHEY_SIMPLEX, 0.5, color, 2)
                            cv2.putText(img, str(&quot;%.2f&quot; % float(conf)), (x2, y2 - box_h), cv2.FONT_HERSHEY_SIMPLEX, 0.5,color, 2)
                            Return[ReturnCounter]=    [x1.item(),y1.item(),x2.item(),y2.item(),conf.item(),cls_conf.item(),classes[int(cls_pred)]]
                            ReturnCounter+=1
                        cv2.imwrite(&quot;Temp2.jpg&quot;,img)
                        return Return
                

device = torch.device(&quot;cuda&quot; if torch.cuda.is_available() else &quot;cpu&quot;)

# Set up model
model = Darknet(&quot;config/yolov3.cfg&quot;, img_size=416).to(device)

model.load_darknet_weights(&quot;weights/yolov3.weights&quot;)

model.eval()  # Set in evaluation mode

classes = load_classes(&quot;data/coco.names&quot;)  # Extracts class labels from file
colors = np.random.randint(0, 255, size=(len(classes), 3), dtype=&quot;uint8&quot;)
Tensor = torch.cuda.FloatTensor if torch.cuda.is_available() else torch.FloatTensor

a=[]
app.run(threaded=True) 


Alright, turns out this is an issue with pyinstaller.
if Pytorch is installed using Conda, it requires the CUDANN , and it won't work with it (ie without that environment)
if you want it to work every where, Pytorch has to be installed using pip.
For reference,
https://github.com/pyinstaller/pyinstaller/issues/2666#issuecomment-508013383
