| <!DOCTYPE html> | |
| <html> | |
| <canvas id="c" width="128" height="128"></canvas> | |
| <script src="glutil.js"></script> | |
| <script id="vshader" type="text/plain"> | |
| attribute vec2 vtxpos; | |
| varying vec2 texpos; | |
| void main() { | |
| texpos = (vtxpos / 2.) + vec2(0.5, 0.5); | |
| gl_Position = vec4(vtxpos, 0, 1); |
| <!-- | |
| Each pixel is read as 4 bytes (traditionally representing red, green, blue and alpha | |
| color channels). But since we have 4 bytes, we can interpret them in any way 4 bytes | |
| can be interpreted, like as a single precision floating point number for example: | |
| http://en.wikipedia.org/wiki/Single-precision_floating-point_format | |
| In this way we can use each pixel to represent a floating point number with a total | |
| precision of 24 bits (equivalent to log10(224) ≈ 7.225 decimal digits): |
| package main | |
| import ( | |
| "log" | |
| "math" | |
| ) | |
| func Round(val float64, roundOn float64, places int ) (newVal float64) { | |
| var round float64 | |
| pow := math.Pow(10, float64(places)) |
A quick overview of the node.js streams interface with basic examples.
This is based on @brycebaril's presentation, Node.js Streams2 Demystified
Streams are a first-class construct in Node.js for handling data.
Think of them as as lazy evaluation applied to data.
The prep-script.sh will setup the latest Node and install the latest perf version on your Linux box.
When you want to generate the flame graph, run the following (folder locations taken from install script):
sudo sysctl kernel.kptr_restrict=0
# May also have to do the following:
# (additional reading http://unix.stackexchange.com/questions/14227/do-i-need-root-admin-permissions-to-run-userspace-perf-tool-perf-events-ar )
sudo sysctl kernel.perf_event_paranoid=0
| A comparison of Collection+JSON, HAL, JSON-LD and SIREN media types. | |
| Discussion at | |
| http://sookocheff.com/posts/2014-03-11-on-choosing-a-hypermedia-format/ |
| # alias to edit commit messages without using rebase interactive | |
| # example: git reword commithash message | |
| reword = "!f() {\n GIT_SEQUENCE_EDITOR=\"sed -i 1s/^pick/reword/\" GIT_EDITOR=\"printf \\\"%s\\n\\\" \\\"$2\\\" >\" git rebase -i \"$1^\";\n git push -f;\n}; f" | |
| # transfer all git repos from one org to another org | |
| gh repo list {orgname} --limit 300 --json nameWithOwner -q '.[].nameWithOwner' | xargs -I {} gh api --method POST repos/{}/transfer -f new_owner={neworg} | |
| # aliases to change a git repo from private to public, and public to private using gh-cli | |
| alias gitpublic="gh repo edit --accept-visibility-change-consequences --visibility public" | |
| alias gitprivate="gh repo edit --accept-visibility-change-consequences --visibility private" |
| The archive paper provides 10 example hard complex divions with answers. It also provides an algorith for measuring the accuracy of the result in "bits", which I have implemented. The robust cdiv algorithm is said to get 53 bits for all but #8 on the hard problems, where it gets 52 bits. I reproduce all of the results (also the default julia / reproduces results for smith's algorithm), except I get 0 bits on #5. I've tracked this down to the division of b/c returning zero inside robust_cdiv2, after r is also zero. But it's not clear how to fix it. | |
| cdiv #1 ,53 bits accurate, 1.1125369292536007e-308 - 1.1125369292536007e-308im | |
| cdiv #2 ,53 bits accurate, 8.98846567431158e307 + 0.0im | |
| cdiv #3 ,53 bits accurate, 1.4334366349937947e104 - 3.645561009778199e-304im | |
| cdiv #4 ,53 bits accurate, 8.98846567431158e307 + 0.0im | |
| cdiv #5 ,0 bits accurate, 3.757668132438133e109 - 2.0e-323im | |
| cdiv #6 ,53 bits accurate, 2.0e-323 + 1.048576e6im | |
| cdiv #7 ,53 bits accurate, 3.8981256045591133e289 + 8.174961907852354e295im |
| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <time.h> | |
| #include <string.h> | |
| extern void dgeqrt3_(long * m, long *n, double * a, long *lda, double *t, long *ldt, long*info); | |
| int main(int argc, char**argv) | |
| { | |
| int in, i; | |
| long n,info=1; |