any function in C or Java (Android) could mess up srand()? -

-

so have c code calculate results based on number generated srand(). if use same seed number, result same.

now have android app load these c code via jni. however, results become different although same seed number being used. have double checked seed number make sure same. however, since both android program , native code pretty complicated, having hard time figure out causing problem.

what sure is, did not use function in java program generate random numbers. presumably srand() not called different seed number every time. can other functions in java or c change random number generated srand()?

thanks!

update: guess question little confusing. clarify, results comparing same platform, different runs. c code use rand() number calculate result based on that. if seed number of srand() same, number rand() should same , hence results should same. somehow use same seed srand(), rand() give me different number... thought on that?

there many different types of random number generators, , not guaranteed same platform platform. if having cross platform 100% predictable solution necessary project, you'll have write own.

it's not bad may sound...

i'd recommend looking random number generation such mersenne twister algorithm (which use in projects), , write small block of code can share amongst projects. gives benefit of being able have multiple generators varying seeds, comes in useful puzzle game, might want predictably random set based on specific seed generate puzzle, clock seeded generator randomizing special fx or other game elements.


Comments

Post a Comment

Popular posts from this blog

plot - Remove Objects from Legend When You Have Also Used Fit, Matlab -

-
Image
i've plotted data points , fitted exponential curve between them using 'fit' in matlab. problem fit-function got fitted line wanted plot, markers on top of regular markers. solved problem plotting wanted markers on top of unwanted couldn't seen. problem. when want show legends dots in there. how can remove markers legend without removing fitted line since both of them hidden inside fit-function? can stop 'fit' plotting unwanted markers? so, want remove blue dot called 'hoff' in picture below. you can leave out legend-entries manually leaving out handles of lines, dont want in legend. try this: %if plot something, want showing in legend, save handle: h_line = plot(x,y) %you dont want show line? dont anything, plot it: plot(mymarker) %then set legend-> can add text legend-entries %a cell-array containing strings want show up: legend([h_line another_line],{'text1' 'text2'}) with example (see comments) came solution:
Read more

java - Why does my date parsing return a weird date? -

-
here code using: string string = "08/07/2013".replace('/', '-'); date date = new simpledateformat("yyyy-mm-dd").parse(string); why date return: "wen jan 3 00:00:00 est 14"? not @ date format told use. edit: need format because database using requires format. the format use parse date string, not match it. using yyyy 08 . use following format: new simpledateformat("dd-mm-yyyy") and why @ replacing / - ? can build pattern original string only: string string = "08/07/2013" date date = new simpledateformat("dd/mm/yyyy").parse(string); and if want date string in yyyy-mm-dd format, can format date using dateformat#format(date) method: string formatteddate = new simpledateformat("yyyy-mm-dd").format(date); see also: change date format in java string simpledateformat java doc
Read more

Need help in packaging app using TideSDK on Windows -

-
i developed application using tidesdk on windows , when click launchapp works fine. moved package , installed imagemagick , wix 3.0 required packaging on windows. clicked on package runtime , cannot guess packaged app is? found file 'installer' in workspace when click on it says installer not find application path . think application not being packaged properly. here log see in tidesdk: preparing package desktop app runtime. 1 moment... staging trial -> copying contents d:\lab\tidesdk\trial d:\lab\tidesdk\trial\packages\win32\bundle\trial -> copying installer c:\programdata\tidesdk\sdk\win32\1.3.1-beta\installer d:\lab\tidesdk\trial\packages\win32\bundle\trial -> copying runtime d:\lab\tidesdk\trial\packages\win32\bundle\trial -> date: d:\lab\tidesdk\trial\packages\win32\bundle\trial\modules\app\1.3.1-beta -> date: d:\lab\tidesdk\trial\packages\win32\bundle\trial\modules\codec\1.3.1-beta -> date: d:\lab\tidesdk\trial\packages\win32\bundle\trial\mod
Read more