java - Why is there no BigDecimal.setPrecision() method? -

-

why there bigdecimal.setscale() method sets decimals value , no mathcontext.setscale() method constructor mathcontext(precision) or other way around why there no bigdecimal.setprecision() method?

edit: there no method mathcontext.setprecision(), constructor mathcontext(precision). edited text. sorry that.

edit2: wanted understand why there 2 ways of approaching scale / precision setting. seems there no real reason have 2 of them regarding answer of richard sitze.

see example makes clear can have strange results playign precision , scale:

mathcontext mc = new mathcontext(2); bigdecimal test = new bigdecimal("100.234", mc); system.out.println("scale: " + test.scale() + ", value: " + test); test.setscale(6); system.out.println("scale: " + test.scale() + ", value: " + test); test = test.add(new bigdecimal("100")); system.out.println("scale: " + test.scale() + ", value: " + test);

results in:

scale: -1, value: 1.0e+2 scale: -1, value: 1.0e+2 scale: 0, value: 200

the results correct regarding settings when set scale 6 expect warning / hint / exception says precision settings not allow scale of 6.

the powers-that-be declared overall precision (total # of digits) can adjusted incidentally changing scale (# of digits right of decimal point).

this appropriate, change precision necessitates change scale. @ best setprecision redundant; having setscale has resulted in cleaner api.

now consider change precision , how result might need rounded. in going through analysis, consider "how many digits should remain after rounding". is scale. such consideration leads question of how scale should changed.

setscale variants specify rounding natural fit. less hypothetical setprecision, begs code comments fill gap (imho).


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