Here is a daily log for Haihao Liu from 2016.6.5 to 2016.8.7 in Saito Lab in Tohoku Univ.
Daily schedule (tentative)†
- 10:00-12:00 Finishing/continuing any work from previous day
- 12:00-13:00 Lunch
- 13:00-14:30 Discussion with Shoufie-san
- 14:30-15:00 Prepare daily report presentation
- 15:00-15:30 Meeting with Saito-sensei
- 15:30-18:00 Continuing work/updating Pukiwiki
Goal of the project†
- To enhance electric field at graphene surface by changing the possible patterns of dielectric thin layers through deep learning algorithms.
- Keywords: graphene, transfer matrix, deep learning
Questions and Answers†
This section is for posting questions from Haihao-san and answers from other group members.
- Please list here with some simple reasons or details.
- For every problem, give a tag double asterisks (**) in the code so that it will appear in the table of contents.
- For the answer, give a tag triple asterisks (***) in the code below the problem in order to make a proper alignment.
- List from new to old.
Q: (Placeholder)†
A: (Placeholder)†
Report†
This part is basically written by Haihao-san. Any other people can add this. Here the information should be from new to old so that we do not need to scroll.
July 11†
- Found 10 conjugacy classes
- Determined isomorphic to D8 x Z2
- Installed GAP, software for computational discrete algebra
- Generated character table for D8 x Z2
To do:
- Find atomic site dot products
- Explain degeneracy?
July 10†
- Visited Matsushima, took boat cruise from Hon-Shiogama
July 8†
- Constructed multiplication table for 4 layers
To do:
- Construct character table for 4 layers
July 7†
- Found formula for number of patterns in each T value for both even and odd # of layers
- Tried making group of symmetry operations on 2-layer lattices, can't include all operations
- Created multiplication table on restricted operations
- Created character table, does not match degeneracy
To do:
- Find basis for each irreducible representation using projection operator
- Construct multiplication table for 4-layer symmetry operations, adding elements as necessary
July 3-6†
- Mid-program meeting in Kyoto
July 1†
- Unable to connect to new drive once again...
- Booted successful by connecting drive via USB, temporary solution, need new HD cable
- Finally able to work on mid-program meeting presentation
- Looked for pattern in number of sequences at each T value
June 30†
- Could not install OS, Mac wouldn't even recognize presence of new hard drive
- After ~15 times opening up Mac, adjusting connection, trying with old HDD, following guides and advice online like using tape, FINALLY some combination of the various fixes worked
- Finally installed OS, restored all my files from Time Machine backup
- Slowly reinstalling apps as needed, less space now
- Meanwhile finally found last two hidden symmetries, to explain all operations to get to different patterns with same T!!
- Arbitrary permutation of double layers, pair inversion
- Can explain N/2 + 1 possible T for even layers using generalized concept of pairs: two of the same separated by even number of layers
To do:
- Make presentation and practice
- Prove total inverse, double permutation, and pair inversion symmetries (probably using fact that P^2 = -Id)
- Find all products of operations, adding elements to make closed group
- Find mathematical pattern for number of sequences in each T for arbitrary N-layer
- Proofread Shoufie-san?s paper
June 29†
- OS install failed, continued trying multitude of things to repair disk, but no matter what unable to repair
- Concluded must be hard drive failure
- BUT saito-sensei gave me a new one! Almost exact same, same brand/year, 320 vs old 500 gb, helped me install
- Discussed mid-program presentation
To do:
- Install OS on new drive and restore files
June 28†
- Computer crashed! Working on repairing computer
- Main partition seems corrupted, reinstalling OS
- Proved cyclic symmetry, as well as several smaller lemmas and corollaries
To do:
June 27†
- Worked on proving cyclic symmetry, found several useful lemmas e.g. regarding product of "chain" matching matrices
- Looking for last hidden symmetry/ies
June 26†
- Visited Sendai Mediatheque (public library/exhibition space)
June 24†
- Found cyclic symmetry
- Found pattern in number of T values: N + 1 for odd, N/2 + 1 for even
- Calculated eigenfunctions and eigenvectors of TMs, will require further investigation
To do:
- Read first 3 chapters of graph theory textbook
- Prove cyclic symmetry
June 23†
- Proved mirror symmetry
- Searched for patterns
- Even and odd have different behavior
- Even has inversion (A<->B) symmetry
June 22†
- Created frequency vs discrete T plot, and T vs Gray code plot for 4 layers
- Identified sequences with identical transmission spectra, found symmetry (e.g. 1101 = 1011)
- Investigated effect of flipping one bit on E field for 4 layer system, still looking at and trying to interpret results (but does not seem to be chaotic at least)
To do:
- Prove using induction that mirrored sequences give identical transmission
June 21†
- Talked to CS major friend about problem, suggested hill climbing and genetic algorithms
- Doesn't think there is a need to use machine learning to predict transmission, because we already have a program to do it exactly! ML is only for when you don't know how to program an algorithm to solve the problem
- Agreed that truly chaotic behavior would make any algorithm, including neural networks, not work (imagine predicting a RNG)
- Tried to see what effect of changing one bit really is
- Found that transmission probability is discrete!
- Changing one bit can only move to one level above or below
- Investigated effect of number of layer and changing dielectric constants, levels only depend on ratio between dielectric constants
To do:
- Create frequency vs discrete T plot, and T vs Gray code plot for small number of layers
June 20†
- Found hole/security flaw in SquirrelMail webmail
- Wrote abstract for Zao meeting
- Researched GPUs for deep learning
- Deployed catnet on Matlab, initial tests were big success
- Figured out MNIST wasn't working because of simple division/rescaling of input, not sure if working
- Learned how to use Matlab read/write to file, played with different formatting for saving data
To do:
- Create database of transmission spectra and E field plots
- Compile training data using random 100-layer sequences?
- Try to train with catnet (imagine)
- Talk to CS friend about how to implement, what type of neural network
June 18†
- Sendai castle adventure
- Performance group
June 17†
- Finally got MatCaffe working, MNIST does not seem to be working
- Installed Caffe (/liu/caffe) on tube61 (Ubuntu 15.04) with ATLAS, CPU-only, ran catnet, still slow, maybe even slower than Mac! (~6 min/20 iterations)
- Moved cat images to flex, continued training
- Installed OpenBLAS on tube61 to try to rebuild Caffe with OpenBLAS
- Installed Intel MKL (commercial, got free student license) on tube60, installed caffe (/liu/research/caffe) on tube 60 (Ubuntu 12.04) with MKL, CPU-only, not yet tested catnet
To do:
- Rebuild with OpenBLAS
- Finish training catnet
- Look into OpenMP for parallel processing support, OpenMP+MKL gives performance comparable to GPU
June 16†
- Downloaded 7000+ cat and dog images
- Training catnet is slow! 5 min/20 iter (1000 in total)
- Downloaded MNIST dataset, trained in about ~10 mins
- Python wrapper installed properly, MATLAB not working, so can't yet deploy
To do:
- Test MNIST by deploying on either Matlab or Python
- Look into GPUs, Saito-sensei might buy one to install on lab server
June 15†
- Talked with Shoufie-san about basics of neural networks, showed him the power of genetic algorithms, discussed ideas on how to use networks to find/generate good sequences
- Continued troubleshooting constant errors, build Caffe, but make runtest failing
- Found that laptop's GPU is too old, not powerful enough, built in CPU-only, finally passed all tests
To do:
- Learn how to use Caffe, run example programs MNIST and catnet
- Install MATLAB and Python wrappers/interface
June 14†
- Installed Homebrew, Miniconda (lightweight Anaconda Python distro)
- Installed CUDA, other libraries Caffe has as dependencies
- Saito-sensei invited me to join Zao NanoCarbon Meeting, gladly accepted!
To do:
June 13†
- Found that integral based error function never gave good score, max ~30 on linear conversion scale for 10 layer system
- Experimented with designing evaluation function based on Q factor for transmission, enhancement and position for E field
- Watching some videos online to learn the basics of how deep learning is implemented, as well as see more examples.
To do:
- File read/write to avoid recalculating every time
- Install Caffe
June 10†
- Adapted MATLAB programs calculate transfer matrix and plot transmission and enhancement for any arbitrary sequence
- Wrote error function
- Lab party!
To do:
- Evaluate scaling functions (0-100)
June 9†
- Wrote MATLAB program to plot intensity of E field in Fibonacci lattice as function of position (z), looked at positions of enhancement
To do:
- Adapt code to calculate transfer matrix and plot transmission and enhancement for any arbitrary sequence
- Design error function (0-100 scale) to measure how close a given transmission or enhancement spectrum is to a target spectrum
- Look into Caffe machine learning
June 8†
- Wrote MATLAB program to construct transfer matrix for n-th Fibonacci lattice
- Plotted transmission probability as a function of frequency, 10th gen made a nice looking fractal
To do:
- Clean up MATLAB code
- Plot E field in Fibonacci lattice as function of distance (z), see points of most enhancement
June 7†
- Walked to campus, took around 30 mins
- Found explicit formula for n-th Fibonacci number, and wrote Python program to generate n-th iteration of the Fibonacci fractal
- Had lunch with Hasdeo-san, bought lunch by weight from cafeteria (entrees 1.4 yen/g, rice .43 yen/g)
- Derived matching (boundary) and propagation matrices in transfer matrix method, used to calculate R and T probabilities for comparison
- Derived E and H relations from Maxwell's equations (Ampere's)
- Introduced myself at group meeting, shared some omiyage from China
- Set up printer over LAN, had to install driver manually
To do:
- Check that theory agrees with Snell's Law
- Construct transfer matrix for n-th Fibonacci lattice
June 6†
- Shoufie-san picked me up from Urban Castle Kawauchi, took me to campus by subway (International Center -> Aobayama, 200 yen ~20 mins total)
- Nugraha-sensei helped me set up lab server access, mail client, etc.
- Bento lunch from Espace Ouvert restaurant (next to 7-11 on bottom floor of new building), ate with Saito-sensei who played his ukulele
- Learned how to derive boundary conditions for EM wave passing from one dielectric media to another, using Maxwell's equations (Faraday's and Ampere's)
- Solved for reflection and transmission probabilities at boundary for normal incident wave
To do:
- Test SHH from dorm room
- Read pages on reflection and transmission of EM waves at boundary, and derive probabilities for both TE and TM both of oblique incident waves
![[PukiWiki]](image/c60.png "[PukiWiki]")
