host/load pretrained weights for 3D resnet

[wyli]

Is your feature request related to a problem? Please describe.
PR Project-MONAI/MONAI#2253 implements a generic version of resnet for spatial 1/2/3D inputs. It'd be very useful for MONAI to provide a further pretrained=True option for the model initialisations. However there is currently some practical issue Project-MONAI/MONAI#2253 (comment):

I was also wondering if I could address some issues I am currently facing with pretraining the network. Personally I would like to implement loading the state dict from the paper "Med3D: Transfer Learning for 3D Medical Image Analysis" (https://github.com/Tencent/MedicalNet), I think this closer resamples the issues monai tries to solve, and I receive better performances for my datasets with this pretrained network vs others (i.e. https://github.com/kenshohara/3D-ResNets-PyTorch).
Problem however is that medicalnet doesn't provide a url download for the state dict only, it only provides a downloadable, 2.7 Gb, zip file which include all pretrained networks and testing data. As I don't want to download the whole zip if someone wants to use a pretrained model, does monai have a zoo storage somewhere for pretrained weights for me to store individual state dicts? Or would you prefer if I would implement the pretrained weights on non medical images? Or no pretraining option at all?

cc @Douwe-Spaanderman

[wyli]

see also Project-MONAI/MONAI#271

[wyli]

now we have an option of the project share drive for this Project-MONAI/MONAI#2489, do you want to revisit the PR? @Douwe-Spaanderman

[JianJuly]

sorry but i didnot find a solution for using pretrained resnet @wyli

[Borda]

I have downloaded the weights and loading with state dict

from monai.networks.nets import resnet10, resnet18, resnet34, resnet50

PATH_PRETRAINED_WEIGHTS = "/home/jovyan/work/pretrained/resnet_10_23dataset.pth"
net = resnet10(
    pretrained=False,
    spatial_dims=3,
)
net.load_state_dict(torch.load(PATH_PRETRAINED_WEIGHTS))

but still getting the following error:

RuntimeError: Error(s) in loading state_dict for ResNet:
	Missing key(s) in state_dict: "conv1.weight", "bn1.weight", "bn1.bias", "bn1.running_mean", "bn1.running_var", "layer1.0.conv1.weight", "layer1.0.bn1.weight", "layer1.0.bn1.bias", "layer1.0.bn1.running_mean", "layer1.0.bn1.running_var", "layer1.0.conv2.weight", "layer1.0.bn2.weight", "layer1.0.bn2.bias", "layer1.0.bn2.running_mean", "layer1.0.bn2.running_var", "layer2.0.conv1.weight", "layer2.0.bn1.weight", "layer2.0.bn1.bias", "layer2.0.bn1.running_mean", "layer2.0.bn1.running_var", "layer2.0.conv2.weight", "layer2.0.bn2.weight", "layer2.0.bn2.bias", "layer2.0.bn2.running_mean", "layer2.0.bn2.running_var", "layer2.0.downsample.0.weight", "layer2.0.downsample.0.bias", "layer2.0.downsample.1.weight", "layer2.0.downsample.1.bias", "layer2.0.downsample.1.running_mean", "layer2.0.downsample.1.running_var", "layer3.0.conv1.weight", "layer3.0.bn1.weight", "layer3.0.bn1.bias", "layer3.0.bn1.running_mean", "layer3.0.bn1.running_var", "layer3.0.conv2.weight", "layer3.0.bn2.weight", "layer3.0.bn2.bias", "layer3.0.bn2.running_mean", "layer3.0.bn2.running_var", "layer3.0.downsample.0.weight", "layer3.0.downsample.0.bias", "layer3.0.downsample.1.weight", "layer3.0.downsample.1.bias", "layer3.0.downsample.1.running_mean", "layer3.0.downsample.1.running_var", "layer4.0.conv1.weight", "layer4.0.bn1.weight", "layer4.0.bn1.bias", "layer4.0.bn1.running_mean", "layer4.0.bn1.running_var", "layer4.0.conv2.weight", "layer4.0.bn2.weight", "layer4.0.bn2.bias", "layer4.0.bn2.running_mean", "layer4.0.bn2.running_var", "layer4.0.downsample.0.weight", "layer4.0.downsample.0.bias", "layer4.0.downsample.1.weight", "layer4.0.downsample.1.bias", "layer4.0.downsample.1.running_mean", "layer4.0.downsample.1.running_var", "fc.weight", "fc.bias". 
	Unexpected key(s) in state_dict: "state_dict". 

[JianJuly]

@Borda I found a solution from https://github.com/Tencent/MedicalNet. This code works.

import torch
from torch import nn
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.autograd import Variable
import math
from functools import partial

__all__ = [
    'ResNet', 'resnet10', 'resnet18', 'resnet34', 'resnet50', 'resnet101',
    'resnet152', 'resnet200'
]


def generate_model(opt):


    assert opt.model_depth in [10, 18, 34, 50, 101, 152, 200]

    if opt.model_depth == 10:
        model = resnet10(
            # sample_input_W=opt.input_W,
            # sample_input_H=opt.input_H,
            # sample_input_D=opt.input_D,
            shortcut_type=opt.resnet_shortcut)
    elif opt.model_depth == 18:
        model = resnet18(
            # sample_input_W=opt.input_W,
            # sample_input_H=opt.input_H,
            # sample_input_D=opt.input_D,
            shortcut_type=opt.resnet_shortcut)
    elif opt.model_depth == 34:
        model = resnet34(
            # sample_input_W=opt.input_W,
            # sample_input_H=opt.input_H,
            # sample_input_D=opt.input_D,
            shortcut_type=opt.resnet_shortcut)
    elif opt.model_depth == 50:
        model = resnet50(
            # sample_input_W=opt.input_W,
            # sample_input_H=opt.input_H,
            # sample_input_D=opt.input_D,
            shortcut_type=opt.resnet_shortcut)
    elif opt.model_depth == 101:
        model = resnet101(
            # sample_input_W=opt.input_W,
            # sample_input_H=opt.input_H,
            # sample_input_D=opt.input_D,
            shortcut_type=opt.resnet_shortcut)
    elif opt.model_depth == 152:
        model = resnet152(
            # sample_input_W=opt.input_W,
            # sample_input_H=opt.input_H,
            # sample_input_D=opt.input_D,
            shortcut_type=opt.resnet_shortcut)
    elif opt.model_depth == 200:
        model = resnet200(
            # sample_input_W=opt.input_W,
            # sample_input_H=opt.input_H,
            # sample_input_D=opt.input_D,
            shortcut_type=opt.resnet_shortcut)


    net_dict = model.state_dict()

    # load pretrain
    if opt.pretrain_path:
        print('loading pretrained model {}'.format(opt.pretrain_path))
        pretrain = torch.load(opt.pretrain_path)
        pretrain_dict = {k: v for k, v in pretrain['state_dict'].items() if k in net_dict.keys()}

        net_dict.update(pretrain_dict)
        model.load_state_dict(net_dict)

        # new_parameters = []
        # for pname, p in model.named_parameters():
        #     for layer_name in opt.new_layer_names:
        #         if pname.find(layer_name) >= 0:
        #             new_parameters.append(p)
        #             break
        #
        # new_parameters_id = list(map(id, new_parameters))
        # base_parameters = list(filter(lambda p: id(p) not in new_parameters_id, model.parameters()))
        # parameters = {'base_parameters': base_parameters,
        #               'new_parameters': new_parameters}

        # return model, parameters
        return model

    return model, model.parameters()


def conv3x3x3(in_planes, out_planes, stride=1, dilation=1):
    # 3x3x3 convolution with padding
    return nn.Conv3d(
        in_planes,
        out_planes,
        kernel_size=3,
        dilation=dilation,
        stride=stride,
        padding=dilation,
        bias=False)


def downsample_basic_block(x, planes, stride, no_cuda=False):
    out = F.avg_pool3d(x, kernel_size=1, stride=stride)
    zero_pads = torch.Tensor(
        out.size(0), planes - out.size(1), out.size(2), out.size(3),
        out.size(4)).zero_()
    if not no_cuda:
        if isinstance(out.data, torch.cuda.FloatTensor):
            zero_pads = zero_pads.cuda()

    out = Variable(torch.cat([out.data, zero_pads], dim=1))

    return out


class BasicBlock(nn.Module):
    expansion = 1

    def __init__(self, inplanes, planes, stride=1, dilation=1, downsample=None):
        super(BasicBlock, self).__init__()
        self.conv1 = conv3x3x3(inplanes, planes, stride=stride, dilation=dilation)
        self.bn1 = nn.BatchNorm3d(planes)
        self.relu = nn.ReLU(inplace=True)
        self.conv2 = conv3x3x3(planes, planes, dilation=dilation)
        self.bn2 = nn.BatchNorm3d(planes)
        self.downsample = downsample
        self.stride = stride
        self.dilation = dilation

    def forward(self, x):
        residual = x

        out = self.conv1(x)
        out = self.bn1(out)
        out = self.relu(out)
        out = self.conv2(out)
        out = self.bn2(out)

        if self.downsample is not None:
            residual = self.downsample(x)

        out += residual
        out = self.relu(out)

        return out


class Bottleneck(nn.Module):
    expansion = 4

    def __init__(self, inplanes, planes, stride=1, dilation=1, downsample=None):
        super(Bottleneck, self).__init__()
        self.conv1 = nn.Conv3d(inplanes, planes, kernel_size=1, bias=False)
        self.bn1 = nn.BatchNorm3d(planes)
        self.conv2 = nn.Conv3d(
            planes, planes, kernel_size=3, stride=stride, dilation=dilation, padding=dilation, bias=False)
        self.bn2 = nn.BatchNorm3d(planes)
        self.conv3 = nn.Conv3d(planes, planes * 4, kernel_size=1, bias=False)
        self.bn3 = nn.BatchNorm3d(planes * 4)
        self.relu = nn.ReLU(inplace=True)
        self.downsample = downsample
        self.stride = stride
        self.dilation = dilation

    def forward(self, x):
        residual = x

        out = self.conv1(x)
        out = self.bn1(out)
        out = self.relu(out)

        out = self.conv2(out)
        out = self.bn2(out)
        out = self.relu(out)

        out = self.conv3(out)
        out = self.bn3(out)

        if self.downsample is not None:
            residual = self.downsample(x)

        out += residual
        out = self.relu(out)

        return out


class ResNet(nn.Module):

    def __init__(self,
                 block,
                 layers,
                 # sample_input_D,
                 # sample_input_H,
                 # sample_input_W,
                 num_seg_classes=2,
                 shortcut_type='B',
                 no_cuda=False):
        self.inplanes = 64
        self.no_cuda = no_cuda
        super(ResNet, self).__init__()
        self.conv1 = nn.Conv3d(
            1,
            64,
            kernel_size=7,
            stride=(2, 2, 2),
            padding=(3, 3, 3),
            bias=False)

        self.bn1 = nn.BatchNorm3d(64)
        self.relu = nn.ReLU(inplace=True)
        self.maxpool = nn.MaxPool3d(kernel_size=(3, 3, 3), stride=2, padding=1)
        self.layer1 = self._make_layer(block, 64, layers[0], shortcut_type)
        self.layer2 = self._make_layer(
            block, 128, layers[1], shortcut_type, stride=2)
        self.layer3 = self._make_layer(
            block, 256, layers[2], shortcut_type, stride=1, dilation=2)
        self.layer4 = self._make_layer(
            block, 512, layers[3], shortcut_type, stride=1, dilation=4)

        self.conv_seg = nn.Sequential(
            nn.ConvTranspose3d(
                512 * block.expansion,
                32,
                2,
                stride=2
            ),
            nn.BatchNorm3d(32),
            nn.ReLU(inplace=True),
            nn.Conv3d(
                32,
                32,
                kernel_size=3,
                stride=(1, 1, 1),
                padding=(1, 1, 1),
                bias=False),
            nn.BatchNorm3d(32),
            nn.ReLU(inplace=True),
            nn.Conv3d(
                32,
                num_seg_classes,
                kernel_size=1,
                stride=(1, 1, 1),
                bias=False)
        )

        for m in self.modules():
            if isinstance(m, nn.Conv3d):
                m.weight = nn.init.kaiming_normal(m.weight, mode='fan_out')
            elif isinstance(m, nn.BatchNorm3d):
                m.weight.data.fill_(1)
                m.bias.data.zero_()

    def _make_layer(self, block, planes, blocks, shortcut_type, stride=1, dilation=1):
        downsample = None
        if stride != 1 or self.inplanes != planes * block.expansion:
            if shortcut_type == 'A':
                downsample = partial(
                    downsample_basic_block,
                    planes=planes * block.expansion,
                    stride=stride,
                    no_cuda=self.no_cuda)
            else:
                downsample = nn.Sequential(
                    nn.Conv3d(
                        self.inplanes,
                        planes * block.expansion,
                        kernel_size=1,
                        stride=stride,
                        bias=False), nn.BatchNorm3d(planes * block.expansion))

        layers = []
        layers.append(block(self.inplanes, planes, stride=stride, dilation=dilation, downsample=downsample))
        self.inplanes = planes * block.expansion
        for i in range(1, blocks):
            layers.append(block(self.inplanes, planes, dilation=dilation))

        return nn.Sequential(*layers)

    def forward(self, x):
        x = self.conv1(x)
        x = self.bn1(x)
        x = self.relu(x)
        x = self.maxpool(x)
        x = self.layer1(x)
        x = self.layer2(x)
        x = self.layer3(x)
        x = self.layer4(x)
        x = self.conv_seg(x)

        return x


def resnet10(**kwargs):
    """Constructs a ResNet-18 model.
    """
    model = ResNet(BasicBlock, [1, 1, 1, 1], **kwargs)
    return model


def resnet18(**kwargs):
    """Constructs a ResNet-18 model.
    """
    model = ResNet(BasicBlock, [2, 2, 2, 2], **kwargs)
    return model


def resnet34(**kwargs):
    """Constructs a ResNet-34 model.
    """
    model = ResNet(BasicBlock, [3, 4, 6, 3], **kwargs)
    return model


def resnet50(**kwargs):
    """Constructs a ResNet-50 model.
    """
    model = ResNet(Bottleneck, [3, 4, 6, 3], **kwargs)
    return model


def resnet101(**kwargs):
    """Constructs a ResNet-101 model.
    """
    model = ResNet(Bottleneck, [3, 4, 23, 3], **kwargs)
    return model


def resnet152(**kwargs):
    """Constructs a ResNet-101 model.
    """
    model = ResNet(Bottleneck, [3, 8, 36, 3], **kwargs)
    return model


def resnet200(**kwargs):
    """Constructs a ResNet-101 model.
    """
    model = ResNet(Bottleneck, [3, 24, 36, 3], **kwargs)
    return model

[Borda]

nice, just wondering how it differs from the MONAI implementation... :)

[Borda]

@JianJuly copy-pasted your suggested code and getting almost the same error:

RuntimeError: Error(s) in loading state_dict for ResNet:
	Missing key(s) in state_dict: "conv1.weight", "bn1.weight", "bn1.bias", "bn1.running_mean", "bn1.running_var", "layer1.0.conv1.weight", "layer1.0.bn1.weight", "layer1.0.bn1.bias", "layer1.0.bn1.running_mean", "layer1.0.bn1.running_var", "layer1.0.conv2.weight", "layer1.0.bn2.weight", "layer1.0.bn2.bias", "layer1.0.bn2.running_mean", "layer1.0.bn2.running_var", "layer1.0.conv3.weight", "layer1.0.bn3.weight", "layer1.0.bn3.bias", "layer1.0.bn3.running_mean", "layer1.0.bn3.running_var", "layer1.0.downsample.0.weight", "layer1.0.downsample.1.weight", "layer1.0.downsample.1.bias", "layer1.0.downsample.1.running_mean", "layer1.0.downsample.1.running_var", "layer1.1.conv1.weight", "layer1.1.bn1.weight", "layer1.1.bn1.bias", "layer1.1.bn1.running_mean", "layer1.1.bn1.running_var", "layer1.1.conv2.weight", "layer1.1.bn2.weight", "layer1.1.bn2.bias", "layer1.1.bn2.running_mean", "layer1.1.bn2.running_var", "layer1.1.conv3.weight", "layer1.1.bn3.weight", "layer1.1.bn3.bias", "layer1.1.bn3.running_mean", "layer1.1.bn3.running_var", "layer1.2.conv1.weight", "layer1.2.bn1.weight", "layer1.2.bn1.bias", "layer1.2.bn1.running_mean", "layer1.2.bn1.running_var", "layer1.2.conv2.weight", "layer1.2.bn2.weight", "layer1.2.bn2.bias", "layer1.2.bn2.running_mean", "layer1.2.bn2.running_var", "layer1.2.conv3.weight", "layer1.2.bn3.weight", "layer1.2.bn3.bias", "layer1.2.bn3.running_mean", "layer1.2.bn3.running_var", "layer2.0.conv1.weight", "layer2.0.bn1.weight", "layer2.0.bn1.bias", "layer2.0.bn1.running_mean", "layer2.0.bn1.running_var", "layer2.0.conv2.weight", "layer2.0.bn2.weight", "layer2.0.bn2.bias", "layer2.0.bn2.running_mean", "layer2.0.bn2.running_var", "layer2.0.conv3.weight", "layer2.0.bn3.weight", "layer2.0.bn3.bias", "layer2.0.bn3.running_mean", "layer2.0.bn3.running_var", "layer2.0.downsample.0.weight", "layer2.0.downsample.1.weight", "layer2.0.downsample.1.bias", "layer2.0.downsample.1.running_mean", "layer2.0.downsample.1.running_var", "layer2.1.conv1.weight", "layer2.1.bn1.weight", "layer2.1.bn1.bias", "layer2.1.bn1.running_mean", "layer2.1.bn1.running_var", "layer2.1.conv2.weight", "layer2.1.bn2.weight", "layer2.1.bn2.bias", "layer2.1.bn2.running_mean", "layer2.1.bn2.running_var", "layer2.1.conv3.weight", "layer2.1.bn3.weight", "layer2.1.bn3.bias", "layer2.1.bn3.running_mean", "layer2.1.bn3.running_var", "layer2.2.conv1.weight", "layer2.2.bn1.weight", "layer2.2.bn1.bias", "layer2.2.bn1.running_mean", "layer2.2.bn1.running_var", "layer2.2.conv2.weight", "layer2.2.bn2.weight", "layer2.2.bn2.bias", "layer2.2.bn2.running_mean", "layer2.2.bn2.running_var", "layer2.2.conv3.weight", "layer2.2.bn3.weight", "layer2.2.bn3.bias", "layer2.2.bn3.running_mean", "layer2.2.bn3.running_var", "layer2.3.conv1.weight", "layer2.3.bn1.weight", "layer2.3.bn1.bias", "layer2.3.bn1.running_mean", "layer2.3.bn1.running_var", "layer2.3.conv2.weight", "layer2.3.bn2.weight", "layer2.3.bn2.bias", "layer2.3.bn2.running_mean", "layer2.3.bn2.running_var", "layer2.3.conv3.weight", "layer2.3.bn3.weight", "layer2.3.bn3.bias", "layer2.3.bn3.running_mean", "layer2.3.bn3.running_var", "layer3.0.conv1.weight", "layer3.0.bn1.weight", "layer3.0.bn1.bias", "layer3.0.bn1.running_mean", "layer3.0.bn1.running_var", "layer3.0.conv2.weight", "layer3.0.bn2.weight", "layer3.0.bn2.bias", "layer3.0.bn2.running_mean", "layer3.0.bn2.running_var", "layer3.0.conv3.weight", "layer3.0.bn3.weight", "layer3.0.bn3.bias", "layer3.0.bn3.running_mean", "layer3.0.bn3.running_var", "layer3.0.downsample.0.weight", "layer3.0.downsample.1.weight", "layer3.0.downsample.1.bias", "layer3.0.downsample.1.running_mean", "layer3.0.downsample.1.running_var", "layer3.1.conv1.weight", "layer3.1.bn1.weight", "layer3.1.bn1.bias", "layer3.1.bn1.running_mean", "layer3.1.bn1.running_var", "layer3.1.conv2.weight", "layer3.1.bn2.weight", "layer3.1.bn2.bias", "layer3.1.bn2.running_mean", "layer3.1.bn2.running_var", "layer3.1.conv3.weight", "layer3.1.bn3.weight", "layer3.1.bn3.bias", "layer3.1.bn3.running_mean", "layer3.1.bn3.running_var", "layer3.2.conv1.weight", "layer3.2.bn1.weight", "layer3.2.bn1.bias", "layer3.2.bn1.running_mean", "layer3.2.bn1.running_var", "layer3.2.conv2.weight", "layer3.2.bn2.weight", "layer3.2.bn2.bias", "layer3.2.bn2.running_mean", "layer3.2.bn2.running_var", "layer3.2.conv3.weight", "layer3.2.bn3.weight", "layer3.2.bn3.bias", "layer3.2.bn3.running_mean", "layer3.2.bn3.running_var", "layer3.3.conv1.weight", "layer3.3.bn1.weight", "layer3.3.bn1.bias", "layer3.3.bn1.running_mean", "layer3.3.bn1.running_var", "layer3.3.conv2.weight", "layer3.3.bn2.weight", "layer3.3.bn2.bias", "layer3.3.bn2.running_mean", "layer3.3.bn2.running_var", "layer3.3.conv3.weight", "layer3.3.bn3.weight", "layer3.3.bn3.bias", "layer3.3.bn3.running_mean", "layer3.3.bn3.running_var", "layer3.4.conv1.weight", "layer3.4.bn1.weight", "layer3.4.bn1.bias", "layer3.4.bn1.running_mean", "layer3.4.bn1.running_var", "layer3.4.conv2.weight", "layer3.4.bn2.weight", "layer3.4.bn2.bias", "layer3.4.bn2.running_mean", "layer3.4.bn2.running_var", "layer3.4.conv3.weight", "layer3.4.bn3.weight", "layer3.4.bn3.bias", "layer3.4.bn3.running_mean", "layer3.4.bn3.running_var", "layer3.5.conv1.weight", "layer3.5.bn1.weight", "layer3.5.bn1.bias", "layer3.5.bn1.running_mean", "layer3.5.bn1.running_var", "layer3.5.conv2.weight", "layer3.5.bn2.weight", "layer3.5.bn2.bias", "layer3.5.bn2.running_mean", "layer3.5.bn2.running_var", "layer3.5.conv3.weight", "layer3.5.bn3.weight", "layer3.5.bn3.bias", "layer3.5.bn3.running_mean", "layer3.5.bn3.running_var", "layer4.0.conv1.weight", "layer4.0.bn1.weight", "layer4.0.bn1.bias", "layer4.0.bn1.running_mean", "layer4.0.bn1.running_var", "layer4.0.conv2.weight", "layer4.0.bn2.weight", "layer4.0.bn2.bias", "layer4.0.bn2.running_mean", "layer4.0.bn2.running_var", "layer4.0.conv3.weight", "layer4.0.bn3.weight", "layer4.0.bn3.bias", "layer4.0.bn3.running_mean", "layer4.0.bn3.running_var", "layer4.0.downsample.0.weight", "layer4.0.downsample.1.weight", "layer4.0.downsample.1.bias", "layer4.0.downsample.1.running_mean", "layer4.0.downsample.1.running_var", "layer4.1.conv1.weight", "layer4.1.bn1.weight", "layer4.1.bn1.bias", "layer4.1.bn1.running_mean", "layer4.1.bn1.running_var", "layer4.1.conv2.weight", "layer4.1.bn2.weight", "layer4.1.bn2.bias", "layer4.1.bn2.running_mean", "layer4.1.bn2.running_var", "layer4.1.conv3.weight", "layer4.1.bn3.weight", "layer4.1.bn3.bias", "layer4.1.bn3.running_mean", "layer4.1.bn3.running_var", "layer4.2.conv1.weight", "layer4.2.bn1.weight", "layer4.2.bn1.bias", "layer4.2.bn1.running_mean", "layer4.2.bn1.running_var", "layer4.2.conv2.weight", "layer4.2.bn2.weight", "layer4.2.bn2.bias", "layer4.2.bn2.running_mean", "layer4.2.bn2.running_var", "layer4.2.conv3.weight", "layer4.2.bn3.weight", "layer4.2.bn3.bias", "layer4.2.bn3.running_mean", "layer4.2.bn3.running_var", "conv_seg.0.weight", "conv_seg.0.bias", "conv_seg.1.weight", "conv_seg.1.bias", "conv_seg.1.running_mean", "conv_seg.1.running_var", "conv_seg.3.weight", "conv_seg.4.weight", "conv_seg.4.bias", "conv_seg.4.running_mean", "conv_seg.4.running_var", "conv_seg.6.weight". 
	Unexpected key(s) in state_dict: "state_dict". 

for loading as:

PATH_PRETRAINED_WEIGHTS = "/home/jirka/Downloads/pretrain/resnet_50_23dataset.pth"
net = resnet50()
state_dict = torch.load(PATH_PRETRAINED_WEIGHTS)
net.load_state_dict(state_dict)
print(net)

[Kaushalya]

I could load most parameters from the state dictionary excluding layerx.0downsample.0.bias by just updating the keys.
Every key in the pre-trained state dict has a prefix 'module.'. I could get rid of most of the key mismatches by removing this prefix from each key.

weights_dict = torch.load(weights_path)
weights_dict = {k.replace('module.', ''): v for k, v in weights_dict['state_dict'].items()}
model.load_state_dict(weights_dict)

Running this code throws the following error. Only the bias of the 4 layers and the weights of the FC layer are missing.

RuntimeError: Error(s) in loading state_dict for ResNet:
	Missing key(s) in state_dict: "layer1.0.downsample.0.bias", "layer2.0.downsample.0.bias", "layer3.0.downsample.0.bias", "layer4.0.downsample.0.bias", "fc.weight", "fc.bias".

We don't need weights of the FC layer if we are finetuning on a different task.

model_dict = model.state_dict()
model_dict.update(weights_dict)
model.load_state_dict(model_dict)

This successfully loads the statedict to the MONAI ResNet implementation.

[Borda]

Yes, that what did in the end too, the rename is critical...
https://github.com/Borda/kaggle_brain-tumor-3D/blob/037c1c3f3a2d601ed272cf7c2199a5d9fed0eb04/kaggle_brain3d/models.py#L15

[bibhabasumohapatra]

trying to do as mentioned in the above comment by @Kaushalya, why I am getting this error?

Update:
I apologize for the hurried implementation, without looking into @Borda 's implementation . . .
It has worked for me, so thanks @Borda

Couldn't we PR this and at least input this Solution . . . its better than getting Error though!!! Thanks Again