Tuesday, March 18, 2014

Episode 32: OpenSCAD


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News
Book of the Show
Tool of the Show

OpenSCAD
  • 3d models
    • Representation of the real world
    • Pure/Mathematical
    • NURBS: Non-uniform rational B-spline
  • Shapes
    • 2d
    • 3d
  • Transformations
    • Affine Transformation
    • 3d Transformation
    • Quaternions (4-D Trick)
  • Boolean Operations
  • Alternatives
    • Blender, 3d Studio Max
    • implicitCad (similar, written in Haskell)
  • RayTracing
    • Scene Description Language
    • Cast rays from camera to light source
    • POVRay

Monday, January 27, 2014

Episode 31: Unix Commands


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News
Interview Tips
  • Read up about the company you’re interviewing with
    • Core Products, Revenue
  • Be Confident, don’t be intimidated
    • Interviewer has studied the problems in advance
    • Attempt every problem, explain your thoughts, leave no stone unturned
  • Prepare a couple good questions for the interviewer
  • Have example code/ open source projects
  • Practice implementing common data structures and algorithms from scratch
    • Binary Trees and Tree Traversal
    • HashMaps
    • Sorting (at least 1 O(n log n) algorithm)
    • Graph Algorithms
    • Recursion & Dynamic Programming
  • TopCoder, Kaggle, Project Euler (and other competition sites)
  • Cracking the Coding Interview
  • Worst Interviewer / Interviewee moments
Book of the Show
Tool of the Show

Unix Commands

Shells
  • Bourne
  • C Shell (csh)
  • Korn Shell (ksh)
  • Thompson Shell (tsh)
  • Bash
Common Commands
  • cat
  • sed & awk
  • diff & patch
  • tar
  • gzip
  • crontab
  • bg, jobs, kill
  • ps, history
  • readlink
  • sort & uniq
  • tr, tr -s
  • cut
  • grep (and grep -r)
  • xargs
  • date
Rare But Useful Commands
  • expand
  • fmt
  • column
Quirky Commands
  • cal
  • banner

Wednesday, November 20, 2013

Episode 30: FPGAs


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Introduction

Patrick's hiking extravaganza.  Jason's move across town.
News
Book of the Show
Tool of the Show

FPGA

History
  • ROM as a PLD
  • CPLD
  • FPGA
Programming
  • Schematic
  • Hardware Definition Language (VHDL & Verilog)
  • RTL vs Structured
  • Interacting with the processor
    • Serial connection
    • Memory Mapped
Pros
  • Parallelism (i/o)
  • Speed
Cons
  • Relatively Difficult to program
  • Testing can be hard
  • Lack of good tool
  • Expensive tools
Features
  • Embedded Cores
  • Soft Cores
  • Reprogramming on the fly

Wednesday, September 4, 2013

Episode 29: CUDA and OpenCL


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Introduction

http://www.origamitessellations.com/
News
Book of the Show
Tool of the Show

CUDA and OpenCL

History
  • GPU: Graphics Processing Unit
    • Vertex: A point in a triangle (poly)
      • Vertex Shader: Transforms properties of a vertex
    • Fragment: A portion of a pixel
      • Fragment Shader: Sets the color & alpha of a pixel for a poly.
    • GPUs are optimized for performing the same operation on many vertices / fragments.
  • GPGPU: General-Purpose Graphics Processing Unit
    • Transform input data to images
    • Turn off any special effects (fog, lighting, etc.)
    • Render exactly one frame
    • Read output data from screen
Common concepts
  • Both CUDA and OpenCL Relieve the developer from having to know about vertex/fragment shaders & graphics processing.
    • Data is organized in n-D arrays
    • Can specify read-only (write-once), write-only (read-never), or read-write.
    • Can copy data to/from GPU with a familiar interface
  • High latency, but can pipeline operations
  • The GPU is organized into warps (groups of threads).  Each thread in a warp must either perform the same operation or do nothing per cycle. (branching is bad)
  • Integer operations are slow, floating point is fast
  • Debugging can be a nightmare (but improving)
CUDA
  • Write .h and .cu files (subset of C)
  • Compile with nvidia compiler, link with your C++ binary.
  • NVIDIA Libraries:
    • cuBLAS (CUDA Basic Linear Algebra Subprograms)
    • cuFFT (CUDA Fast Fourier Transform)
  • Language bindings for many languages (Python, Java, Lua, etc.)
OpenCL
  • A standard (like OpenGL) that has CPU and GPU implementations
  • Easy to debug on the CPU before running on the GPU
  • Not limited to NVIDIA graphics cards (good for distribution)

Thursday, June 13, 2013

Episode 28: Applied Artificial Intelligence


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Feedback
  • 107 Reviews on iTunes
  • America's Test Kitchen
  • Picking a Programming Language
Tool of the Show
Book of the Show

Applied Artificial Intelligence

Common Terms
  • Objective Function
  • Features
  • Under/Over Fitting
  • Classification / Regression / Control
Methods
  • Supervised (Learn a function from residuals)
    • Gradient-Descent
    • Perceptron
    • Back-Propagation (Non-Linear)
  • Reinforcement Learning (Estimating value from reward)
    • Minimax, Monte Carlo Tree Search (MCTS)
    • Temporal Difference Learning
    • Genetic Algorithms
    • NEAT
  • Unsupervised (Clustering & Dimensionality Reduction)
    • K-Means
    • PCA
    • Neural Gas
Challenges
  • Making an objective function
  • Training-Serving Skew
  • Modeling
    • Linearizing
    • Feature-Extraction & Discretization
    • Kernels
  • Measuring Performance

Friday, May 31, 2013

Episode 27: Artificial Intelligence Theory


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News
Tool of the Show
Book of the Show


Theoretical Artificial Intelligence

History
  • The Turk 1770
  • Turing Test, Three Laws of Robotics(1942)
  • First neural net: 1951
  • Arthur Samuel’s Checkers AI: ‘51
  • Golden Age (‘56 - ‘74)
  • AI Winter (74-80)
  • Renaissance (1990+)
  • Deep Blue vs kasparov 1996
What is AI?
  • "Real" Intelligence versus Artificial Intelligence
  • Common-Sense Knowledge
  • Goals: Deducting, Reasoning, Problem Solving
Challenges
  • “Strong AI” (General AI): Artificial Intelligence that meets or exceeds human intelligence at every level.
  • Combinatorial explosion in planning
  • Knowledge representation
  • The frame problem
AI Projects

Episode 25: Unit Testing


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News
Tool of the Show
Book of the Show


Unit Testing

History
  • 1956 “The Debugging Period”
    • Testing associated with debugging
  • 1957 - 1978 “Demonstration Period”
    • Show software satisfies requirements
  • 1979 - 1982 “Destruction Oriented Period”
    • Testing should find errors
  • 1983 - 1987 “Evaluation Oriented Period”
    • Testing to measure quality
  • 1988+ “Prevention-Oriented”
    • Detect and prevent faults
Features
  • Prove correctness
  • Mocking
  • Code Coverage (Statement  and branch)
Strengths
  • Establish a contract for the code
  • Make sure there is no unreachable code
  • Force writing testable code
  • Can serve as programmatic documentation
Weaknesses
  • Time consuming
  • Establish constraints that may not be valid
  • False sense of security
Tools
  • Java
    • JUnit
    • EasyMock, Mockito
  • C++
    • cpptest
    • gmock