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xiaotian zhu
50 articles
My Web Markups - xiaotian zhu
kumar-shridhar/Master-Thesis-BayesianCNN: Master Thesis on Bayesian Convolutional Neural Network using Variational Inference
 
github.com
698
  • by finding the parameter that maximizes the log-likelihood of the observed sample . This is the same as maximizing the likelihood function
  • log-likelihood function is the function defined by
  • a function of for fixed (i.e., for the sample we have observed), it is called likelihood (or likelihood function) and it is denoted by .
  • distribution of belongs to a parametric family: there is a set of real vectors (called the parameter space) whose elements (called parameters) are put into correspondence with the distributions that could have generated ;
  • realization of a random vector ,
  • e ,
  • a sample
  • the likelihood is a function that associates to each parameter the probability (or probability density) of observing the given sample
Log-likelihood
8 annotations
 
www.statlect.com
445
  • the number of ego_pose records in our loaded database is the same as the number ofsample_data records. These two records exhibit a one-to-one correspondence
  • ego_pose contains information about the location (encoded in translation) and the orientation (encoded in rotation) of the ego vehicle body frame
  • the translation and the rotation parameters are given with respect to the ego vehicle body frame
Open Datasets: nuScenes Tutorial - Scale
3 annotations
 
scale.com
671
  • Each function then returns a TensorOptions object preconfigured with that axis, but allowing even further modification via the builder-style methods shown above
  • The result of the conversion, float_tensor, is a new tensor pointing to new memory, unrelated to the source source_tensor.
  • .to(torch::kFloat32)
  • when there is only a single axis we would like to change compared to its default value, we can pass only that value.
Tensor Creation API — PyTorch master documentation
4 annotations
 
pytorch.org
466
  • HKUST
In utils/quant_dorefa.py, Line 46,Why does it multiply max_w ? · Issue #10 · zzzxxxttt/pytorch_DoReFaNet
1 annotation
 
github.com
357
  • CAS, interested in object detection, remote s
  • UCAS
Stargazers · zzzxxxttt/pytorch_simple_CenterNet_45
2 annotations
 
github.com
557
  • skew coefficient
  • optical center
  • focal length
  • translation, t.
  • rotation, R
  • intrinsic parameters represent a projective transformation from the 3-D camera’s coordinates into the 2-D image coordinates
  • extrinsic parameters represent a rigid transformation from 3-D world coordinate system to the 3-D camera’s coordinate system
  • camera coordinates are mapped into the image plane using the intrinsics parameters
  • world points are transformed to camera coordinates using the extrinsics parameters
What Is Camera Calibration? - MATLAB & Simulink - MathWorks 中国
9 annotations
 
ww2.mathworks.cn
419
Tensor Indexing API — PyTorch master documentation
 
pytorch.org
488
  • model parameters must be broadcast to the other GPUs at the beginning of the next iteration
  • gradients are reduced on the master GPU
  • loss value is scattered across the GPUs and each GPU runs the backward pass to compute gradients
  • network outputs are then gathered on the master GPU
  • scattering the sub mini-batches across the GPU network. Each GPU runs the forward pass on its sub mini-batch on a separate thread
  • data-parallel
  • the available parallelism on the GPU is fully utilized at batch size ~8
Distributed data parallel training using Pytorch on AWS – Telesens
7 annotations
 
www.telesens.co
679
  • SECOND
  • ranked based on the moderately difficult results
  • pedestrians and cyclists we require a 3D bounding box overlap of 50%
  • For cars we require an 3D bounding box overlap of 70%
  • objects in don't car areas do not count as false positives
The KITTI Vision Benchmark Suite
5 annotations
 
www.cvlibs.net
489
  • unpack the entire expression that contains the parameter pack. Not just the parameter pack
c++ - How does folding over comma work? - Stack Overflow
1 annotation
 
stackoverflow.com
536
cuda - What does nvprof output: "No kernels were profiled" mean, and how to fix it - Stack Overflow
 
stackoverflow.com
677
  • removes the constraint that observed states only depend on the hidden state in the same event
  • the observed states only depend on hidden state of current event
  • regard every event at a particluar time step as a Naive Bayes model
  • the value of a particular feature is independent of the value of any other feature given the class variable
From Naive Bayes to Linear-chain CRF | CN Yah
4 annotations
 
cnyah.com
579
Halmstad-University/SalsaNext: Uncertainty-aware Semantic Segmentation of LiDAR Point Clouds for Autonomous Driving
 
github.com
539
traveller59/spconv: Spatial Sparse Convolution in PyTorch
 
github.com
366
  • GG\boldsymbol{G}是对矩阵ggg各个元素取指数后的矩阵
  • H(yt+1|x)H(yt+1|x)H(y_{t+1}|\boldsymbol{x})是编码模型h(yt+1|x)h(yt+1|x)h(y_{t+1}|\boldsymbol{x})（RNN、CNN等）对位置t+1t+1t+1的各个标签的打分的指数
  • 终点
  • 指数和
  • 计算到时刻ttt的归一化因子记为Zt
  • ggg实际上就是一个有限的、待训练的参数矩阵而已
  • 只需要对每一个标签和每一个相邻标签对分别打分，然后将所有打分结果求和得到总分
  • 关联仅发生在相邻位置
  • 因为这个是条件分布，所以归一化因子跟xx\boldsymbol{x}有关
简明条件随机场CRF介绍（附带纯Keras实现） - 科学空间|Scientific Spaces
9 annotations
 
kexue.fm
622
  • call the operator handle with all of the arguments passed into the dispatching function.
  • overload name of the operator
  • name of the operator
  • dispatcher
  • typed operator handle
  • the operator that we are going to dispatch to
  • look up a typed operator handle from the dispatcher corresponding to the operator that we are going to dispatch to
  • single
  • The TORCH_LIBRARY_IMPL lets us register implementations for operators on a specific dispatch key
  • the simple way of registering it (def("myadd", myadd_cpu)) would register the kernel to run in all cases, even if the tensor is not a CPU tensor!
  • The dispatcher determines what the highest priority dispatch key is at the time you call an operator
  • first execute the Autograd kernel, and then we redispatch to the CPU or CUDA kernel depending on the device types of the passed in tensors.
Dispatcher in C++ — PyTorch Tutorials 1.6.0 documentation
12 annotations
 
pytorch.org
380
  • Parameter pack expansion: expands to comma-separated list of zero or more patterns. Pattern must include at least one parameter pack.
Parameter pack(since C++11) - cppreference.com
1 annotation
 
en.cppreference.com
450
  • it learns a representation that uses cues from other tasks, such as segmentation
  • our model can learn multi-task weightings and outperform separate models trained individually on each task.
  • use homoscedastic uncertainty to weight the losses in multi-task learning models
  • because it is tested on the same problem with the same sensor.
  • train a model with dropout. Then, at test time, rather than performing model averaging, we can stochastically sample from the network with different random dropout masks. The statistics of this distribution of outputs will reflect the model’s epistemic uncertainty
  • model distributions over models and their parameters
  • the uncertainty parameter will no longer be a model output, but a free parameter we optimise.
  • learned loss attenuation
  • model Heteroscedastic aleatoric uncertainty just by changing our loss functions
  • Bayesian deep learning models typically form uncertainty estimates by either placing distributions over model weights, or by learning a direct mapping to probabilistic outputs
  • when the model is unfamiliar with the footpath, and the corresponding increased epistemic uncertainty
  • aleatoric uncertainty captures object boundaries where labels are noisy
  • Task-dependant or Homoscedastic uncertainty is aleatoric uncertainty which is not dependant on the input data. It is not a model output, rather it is a quantity which stays constant for all input data and varies between different tasks
  • Data-dependant or Heteroscedastic uncertainty is aleatoric uncertainty which depends on the input data and is predicted as a model output
  • Aleatoric uncertainty captures our uncertainty with respect to information which our data cannot explain
  • model uncertainty
  • Epistemic uncertainty captures our ignorance about which model generated our collected data
Deep Learning Is Not Good Enough, We Need Bayesian Deep Learning for Safe AI - Home
17 annotations
 
alexgkendall.com
445
  • By thread indexing we are getting a unique number for each thread and each block in a grid
CUDA Thread Indexing. When I was learning CUDA programming, I… | by Anuradha Karunarathna | Noteworthy - The Journal Blog
1 annotation
 
blog.usejournal.com
415
  • CRFs are indeed basically the sequential version of logistic regression
  • each feature function fjfjf_j
  • how much we suspect that the current word should be labeled as an adjective
  • a function that takes in as input
Introduction to Conditional Random Fields
4 annotations
 
blog.echen.me
648
  • Rvalue references allow a function to branch at compile time
  • X& is now also called an lvalue reference
  • If X is any type, then X&& is called an rvalue reference to X
Page 3 of: C++ Rvalue References Explained
3 annotations
 
thbecker.net
384
  • - Added self.use_ninja = False in the __init__ function of BuildExtension class in ...\site-packages\torch\utils\cpp_extension.py, to get more informative output about where the build errors are. Instead of hacking the code like that, there might be a way to pass some argument to disable ninja build; I didn't explore that. - For "Warning: Error checking compiler version for cl: [WinError 2] The system cannot find the file specified". - In each Anaconda prompt, before "cl" is invoked, we need to run appropriate Visual Studio Developer command file to set up the environment variables. Example: "call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars64.bat". The exact batch file to execute depends on the architecture for which we want to compile etc. - I decided not to use develop.sh, because it leads to "Python: unknown command" error due to bash not being aware of Anaconda environment (??). The first line in develop.sh is for cleaning up -- which can be done manually. I chose to directly run the second line "python setup.py develop". - Handling the <tr1/functional> file not found error - "tr1" was a temporary namespace that was in use when "functional" was still not part of the C++ standard. - In "sparseconfig.h" under "sparseconvnet\SCN\Metadata\sparsehash\internal", made the following changes: - Changed "#define HASH_FUN_H <tr1/functional>" to "#define HASH_FUN_H <functional>" - Changed "#define HASH_NAMESPACE std::tr1" to "#define HASH_NAMESPACE std" - In cpp_extension.py, line 1398, set num_workers = 1 - On line 297, self.use_ninja = False - There are several occurrences of "or" (instead of "||") and "and" (instead of "&&") in Metadata.cpp, NetworkInNetwork.cpp etc. To get them to build with Microsoft compiler, we need to pass the "/permissive-" option (Note: Though '/Za' flag is supposed to fix them, it causes other errors). Updated setup.py to add that option. - c:\blahblah\SparseConvNet\sparseconvnet\SCN\Metadata\sparsehash\internal\hashtable-common.h(166): error C2760: syntax error: unexpected token 'typedef', expected ';' - In hashtable-common.h, changed the definition of SPARSEHASH_COMPILE_ASSERT(expr, msg) to static_assert(expr, "message") - c:\blahblah\SparseConvNet\sparseconvnet\SCN\CUDA/SparseToDense.cpp(29): error C2664: 'at::Tensor &at::Tensor::resize_(c10::IntArrayRef,c10::optional<c10::MemoryFormat>) const': cannot convert argument 1 from 'std::array<long,3>' to 'c10::IntArrayRef' - Changed "std::array<long, Dimension + 2> sz" to "std::array<int64_t, Dimension + 2> sz" - c:\blahblah\SparseConvNet\sparseconvnet\SCN\CUDA/BatchNormalization.cu(83): error: calling a __host__ function("pow<float, double, (int)0> ") from a __global__ function("BatchNormalization_f_test<float, (int)16, (int)64> ") is not allowed - Changed "pow(_saveInvStd / nActive + eps, -0.5)" to "pow(double(_saveInvStd / nActive + eps), -0.5)". Otherwise, the calling signature happens to be pow(float, double) which does not correspond to the signature of any variant of "pow" function available on CUDA. - Big one: After doing all of the above, I got the code to compile, but a mysterious link error appeared. The error said something like this: sparseconvnet_cuda.obj : error LNK2001: unresolved external symbol "public: long * __cdecl at::Tensor::data_ptr<long>(void)const " (??$data_ptr@J@Tensor@at@@QEBAPEAJXZ) - This was too mysterious. A knowledgeable poster on CUDA forum offered a clue to help this. As that poster said, code meant to be cross-platform should not be using "long". It would end up being 32 bit wide on 64-bit Windows machines while being 64 bit wide on 64-bit Linux machines. - Replaced all occurrences of "long" by "int64_t" and the mysterious link error went away.
Does the sparseConvNet have windows version? · Issue #128 · facebookresearch/SparseConvNet
1 annotation
 
github.com
570
  • You can also check the instance with multiple types
Python isinstance() explained with examples [Guide]
1 annotation
 
pynative.com
519
  • when compiling a given target
  • The named <target> must have been created by a command such as add_executable() or add_library()
target_include_directories — CMake 3.18.2 Documentation
2 annotations
 
cmake.org
498
  • the entire GPU grid is split into as many blocks of 1 x 1024 threads as are required to fill our matrices with one thread per component
  • each CUDA block will have 1024 threads
  • If you wanted to dispatch over all types and not just floating point types (Float and Double), you can use AT_DISPATCH_ALL_TYPES.
  • AT_DISPATCH_FLOATING_TYPES macro
  • kernel launch (indicated by the <<<...>>>).
  • .cu
  • this file will also declare functions that are defined in CUDA (.cu) files
  • write a C++ file which defines the functions that will be called from Python
Custom C++ and CUDA Extensions — PyTorch Tutorials 1.6.0 documentation
8 annotations
 
pytorch.org
396
  • A type generator is a template whose only purpose is to synthesize a new type or types based on its template argument(s)
  • A traits class provides a way of associating information with a compile-time entity
Generic Programming Techniques
2 annotations
 
www.boost.org
584
vscode settings - How do I hide certain files from the sidebar in Visual Studio Code? - Stack Overflow
 
stackoverflow.com
441
  • module name (example)
First steps — pybind11 2.5.dev1 documentation
1 annotation
 
pybind11.readthedocs.io
648
  • 只要我们观察到了某个时间反转的物体，我们就可以断定这个物体的正常版本必定在未来某个时刻进入时间反转机
(6 封私信 / 1 条消息) 《信条》讲了一个什么故事？ - 知乎
1 annotation
 
www.zhihu.com
341
Docker
 
www.yolomax.com
464
  • 判别模型是直接对 建模
(5 封私信) 如何用简单易懂的例子解释条件随机场（CRF）模型？它和HMM有什么区别？ - 知乎
1 annotation
 
www.zhihu.com
568
  • the current dice label only depends on the previous one
  • dice is fair
  • current dice label
  • only a viable strategy when I’m equally likely to use either dice
  • for each roll
Conditional Random Field Tutorial in PyTorch 🔥 | by Freddy Boulton | Towards Data Science
5 annotations
 
towardsdatascience.com
553
  • The at::Tensor class in ATen is not differentiable by default. To add the differentiability of tensors the autograd API provides, you must use tensor factory functions from the torch:: namespace instead of the at:: namespace
PyTorch C++ API — PyTorch master documentation
1 annotation
 
pytorch.org
433
  • when vector goes out of scope no destructors are automatically called.
  • assign = "actually" copies data.
  • W
  • e created an array of objects stored by value. And no. Removing * from declaration doesn't automatically make pointer variable reference.
The new C++ 11 rvalue reference && and why you should start using it - CodeProject
4 annotations
 
www.codeproject.com
413
  • An rvalue is an expression that is not an lvalue
  • An lvalue is an expression that refers to a memory location and allows us to take the address of that memory location via the & operator
  • Rvalue references solve at least two problems: Implementing move semantics Perfect forwarding
  • Rvalue references are a feature of C++ that was added with the C++11 standard. What makes rvalue references a bit difficult to grasp is that when you first look at them, it is not clear what their purpose is or what problems they solve. Therefore, I will not jump right in and explain what rvalue references are. Instead, I will start with the problems that are to be solved and then show how rvalue references provide the solution. That way, the definition of rvalue references will appear plausible and natural to you. Rvalue references solve at least two problems: Implementi
C++ Rvalue References Explained
4 annotations
 
thbecker.net
399
  • templates are just a big state machine.
  • if we call a templated method with two different template arguments, they will actually be compiled into two totally different calls
Template Metaprogramming: Compile time loops over class methods | by Niko Savas | Medium
2 annotations
 
medium.com
421
  • cudaMemcpy
  • CPU上调用，GPU上执行
  • __global__
  • __global__函数的返回值必须设置为void
  • global memory
  • grid
  • shared memory
  • 线程块
  • 线程
  • registers
  • 线程
  • local memory
  • 一个SM可以同时拥有多个blocks，但需要序列执行
  • 一个kernel其实由一个grid来执行，一个kernel一次只能在一个GPU上执行
  • kernel调用时也必须通过执行配置<<<grid, block>>>来指定kernel所使用的网格维度和线程块维度
CUDA编程之快速入门 - Madcola - 博客园
15 annotations
 
www.cnblogs.com
473
  • 由于托管内存自动进行数据传输，这里要用cudaDeviceSynchronize()函数保证device和host同步
  • 使用cudaMallocManaged函数分配托管内存
  • block大小一般要设置为32的倍数
  • 一个线程块只能在一个SM上被调度。SM一般可以调度多个线程块
  • gridDim
  • blockDim
  • threadIdx
  • blockIdx
  • 多线程
  • 一个线程块里面包含很
  • kernel在device上执行时实际上是启动很多线程
  • 但可和__device__，此时函数会在device和host都编译
  • host不会等待kernel执行完就执行下一步
  • threadIdx
  • 每一个线程
  • 核函数用__global__符号声明
  • 用<<<grid, block>>>来指定kernel要执行的线程数量
  • device指代GPU及其内存
  • host指代CPU及其内存
CUDA编程入门极简教程 - 知乎
19 annotations
 
zhuanlan.zhihu.com
448
  • most non-trivial code has a "sweet spot" in the 128-512 threads per block range
  • number of threads per block should be a round multiple of the warp size, which is 32
  • 16kb/48kb/96kb of shared memory
  • Each block
  • 8k/16k/32k/64k/32k/64k/32k/64k/32k/64k registers
  • Each block
  • [1024,1024,64]
  • each block
  • s
  • 1024 thread
  • Each block
  • n
  • cannot have more tha
performance - How do I choose grid and block dimensions for CUDA kernels? - Stack Overflow
13 annotations
 
stackoverflow.com
339
  • If you're designing something that requires a lot of shared memory, then more threads-per-block might be advantageous
dimensions - CUDA determining threads per block, blocks per grid - Stack Overflow
1 annotation
 
stackoverflow.com
436
  • o
  • another distribution q(w|D) with some variational parameters θ.
  • P(w|D) (our posterior from above)
  • P(x) is the evidence
  • P(x|θ) which is the likelihood
  • P(θ) which is our prior
  • take a variational approximation rather than a Monte Carlo scheme to find the approximate Bayesian posterior distribution
  • only point estimates of the weights are achieved in the network. As a result, these networks make overconfident predictions and do not account for uncertainty in the parameters
  • Aleatoric uncertainty, on the other hand, is modelled by placing a distribution over the output of the model.
  • Epistemic uncertainty is modelled by placing a prior distribution over a model’s weights and then trying to capture how much these weights vary given some data
  • heteroscedastic uncertainty which depends on the inputs to the model
  • homoscedastic uncertainty, the uncertainty which stays constant for different inputs
  • Epistemic uncertainty represents the uncertainty caused by the model itself
  • Aleatoric uncertainty measures the noise inherent in the observations
  • A prior probability distribution is defined before observing the data, the learning happens and the distribution transforms into posterior distributions once the data is observed
Bayesian Neural Network Series Post 2: Background Knowledge | by Kumar Shridhar | NeuralSpace | Medium
15 annotations
 
medium.com
587
  • allows Tensor objects to be zero-dimensional
  • Scalars can be implicitly constructed from C++ number types
  • cannot be resized
  • from_blob
  • 32
  • 32
  • may lead to overflows
  • quite a bit faster on CUDA
  • .packed_accessor64<float,2>()
  • .accessor<float,2>()
  • recommended to use accessors for CPU tensors and packed accessors for CUDA tensors
  • accessors are not compatible with CUDA tensors
  • Accessors are temporary views of a Tensor. They are only valid for the lifetime of the tensor that they view and hence should only be used locally in a function, like iterators.
  • Accessors then expose an API for accessing the Tensor elements efficiently.
  • ATen’s API is auto-generated from the same declarations PyTorch uses so the two APIs will track each other over time.
Tensor Basics — PyTorch master documentation
15 annotations
 
pytorch.org
398
  • in the current function or directory scope
set — CMake 3.18.2 Documentation
1 annotation
 
cmake.org
487
  • named <target> must have been created by a command such as add_executable() or add_library()
target_link_libraries — CMake 3.18.2 Documentation
1 annotation
 
cmake.org
467
  • 每个filter i 都自己有一个rule book
论文阅读：Submanifold Sparse Convolutional Networks - 知乎
1 annotation
 
zhuanlan.zhihu.com
484
  • option
  • add_library
  • CMAKE_CXX_STANDARD 11
  • TutorialConfig.h.in
  • VERSION 1.0
  • Upper, lower, and mixed case commands are supported by CMake
CMake Tutorial — CMake 3.18.2 Documentation
6 annotations
 
cmake.org
407
  • All members of the exponential family have conjugate priors
  • if the posterior distributions p(θ | x) are in the same probability distribution family as the prior probability distribution p(θ), the prior and posterior are then called conjugate distributions, and the prior is called a conjugate prior for the likelihood function p(x | θ)
Conjugate prior - Wikipedia
2 annotations
 
en.wikipedia.org
646
  • they all have a normal distribution with mean and variance
  • the covariance matrix of is diagonal implies that the entries of are mutually independent
  • mean equal to and covariance matrix equal to
  • is an unobservable error term
  • is the dependent variable
  • is the vector of regression coefficients
  • is a vector of regressors
Linear regression - Maximum likelihood estimation
7 annotations
 
www.statlect.com
472
  • 在贝叶斯概率论中，如果后验分布 p（θx）与先验概率分布 p（θ）在同一概率分布族中，则先验和后验称为共轭分布，先验称为似然函数的共轭先验
(16 封私信 / 16 条消息) 首页 - 知乎
1 annotation
 
www.zhihu.com
620