PPT-13 – Program Correctness

25 Reasoning about Programs Assertions and Loop Invariants 26 Efficiency of Algorithms 1 Attendance Quiz 10 Program Correctness 2 Tip 13 n Confusion Program Correctness 3 Internally all applications use n to indicate line termination. The bit stream representation of a symbol is called the codeword of that symbol Di64256erent error control mechanisms Linear Block Codes Repetition Codes Convolution Codes brPage 2br Linear Block Codes A code is linear if two codes are added using m Rustan M Leino Microsoft Research leinomicrosoftcom Abstract Traditionally the full verication of a programs functional correctness has been obtained with pen and paper or with interactive proof assistants whereas only reduced verication tasks such berkeleyedu Abstract Writing correct explicitlyparallel programs can be very challenging While the functional correctness of a pro gram can often be understood largely sequentially a software engineer must simultaneously reason about the nondetermini We discuss a collection of mechanized formal proofs of sym metric key block encryption algorithms AES MARS Twosh RC6 Serpent IDEA and TEA performed in an implementation of higher order logic For each algorithm functional correctness namely that de c Susan . Owicki. & David . Gries. Presented by Omer Katz. Seminar in Distributed Algorithms Spring 2013. 29/04/13. What’s next?. What are we trying to do?. The sequential solution. The parallel solution. K. Rustan M. Leino. Research in Software Engineering (. RiSE. ). Microsoft Research, Redmond. Lecture 0. LASER Summer . School 2011. Elba, Italy. 4. . September 2011. Reasoning about programs. Central to any programming task.  . Name . E-mail  . Country, City, University.   . Omer . Subasi.  .  . osubasi@ku.edu.tr.  .  . Turkey,. Istanbul, . Koc. . University .  . Anton . Dergunov.  .  . anton.dergunov@mail.ru. Yancy. Vance . Paredes. Outline. Background. Motivation. Huffman Algorithm. Sample Implementation. Running Time Analysis. Proof of . Correctness. Application. Background. Lossless compression where around 20% to 90% of savings in space. . is a slippery, slippery slope. Implications for technical communication. Once we’re done editing, we lose control of our word’s intended meanings. Misused Words. Example. : Cree Indians were a . (CS1020 AY2015/6 . Sem. 2). Getting Started. Logging in. Visit . https://codecrunch.comp.nus.edu.sg/. using IE or Chrome.. Use your . NUSNET id . and . password. to login.. 2. (Note: . CodeCrunch. Inference. Hiroshi Unno (University of Tsukuba). Joint work with: Naoki Kobayashi, . Tachio. Terauchi, . Ryosuke. Sato, Takuya . Kuwahara. , . Kodai. Hashimoto, . Sho. Torii. 2015/7/4. HOPA 2015. Verification. Orna Grumberg. Lectures Material. winter . 2016-17. Lecture 3. Floyd Proof Rule for Partial Correctness. To prove . {q. ₁. }P{q. ₂. } . :. Choose. a set of . cut points . such that:. Ali Mili, NJIT. Third Spring Festival Workshop. Karuizawa. , March 2017. Acknowledgements. In collaboration . with. M. . Frias (Argentina), . J. . . Desharnais. (CDN), . W. . . Ghardallou. (TN), . N. Chapter Objectives. To understand the differences between the three categories of program errors. To understand what it means to throw an exception and how to throw an exception in a function. To understand the effect of an uncaught exception and why you should catch exceptions.