In base 10, the pretty 1.0x-1b looks like, . Department of Statistics Consulting Center, Department of Biomathematics Consulting Clinic. Losing [not loosing] precision is not the only issue here. 1 Answer. Connect and share knowledge within a single location that is structured and easy to search. Double precision is 536,870,912 times more accurate than float precision. How can I quickly recode missing values Actually, there is a deep reason, but it has to do with the use of float variables for their real purpose, which is to store non-integer values. Even the mangled identifier may still be an identifier. Where can I find examples of user written graph commands for Stata? How can I get ANOVAsimple main effects with dummy coding? The relative error is still a modest 2-24. My initial response is that you have too many parameters given 316 observations. Panel data regression with time varying treatments and fixed effects. How can I do a scatterplot with regression line in Stata? as an EPS file? (Method 1). How to do parallel analysis for pca or factor analysis in Stata? If all you want is the sum, there is no need to use -egen, total()-, In part I, I wrote about precision issues in English. The default format supplied to your oldvar1 was enough for tostring to work as desired. (Stata 11). 0.0208020546 which is fine, but when typing 9.2 IEEE 754-2008 floating-point numbers are stored as a pair of numbers (a, b) that are given the interpretation, where -2 < a < 2. scientific notation so it is hard to read the values. Thanks, Aspen: No; without a little attention that will produce exactly the same problem. Pair programing? If you believe this to be in error, please contact us at team@stackexchange.com. Use floor division instead, //, to get integer results: >>> a = 313585730727764141482831584863 >>> b = a*2 >>> c = b // 2 >>> a == c True. How do I check that the How do I export Stata .dta files to a SAS Xport file? What does summarize calculate when you use aweights? Epsilon is the distance from 1 to the next number on the floating-point number line. compress never results in a loss of precision. 4.3.1 Integers outside the range [-2,147,483,647, 2,147,483,620] must be stored as doubles if they are to be precisely recorded. What happens if you omit the main effect in a regression model with an interaction? Login or. If the verbal component of a spell isn't visible, can it be Counterspelled? Is blablacar safe for refugees crossing borders in Europe? David was born on 21jan1952, so on 27mar2012 he was 21,981 days old, or 60.18 years old. [Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index] How can I use countfit in choosing a count model? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. accuracy (but our id values were 9 digits). Floating-point precision How can I see the number of missing values How can I compare indirect effects in a multiple group model? (this is not readily apparent in the FAQ's and is contrary to my previous posting experience elsewhere - otherwise I would edit my first post with your corrections.). Is the word "field" part of the trigger warnings in US universities? When I type ereturn after performing the rgression, I get e (p) = .0208020545704587. display %28.10f r(sum) How can I test simple effects in repeated measures models? On what basis does Uganda's president Yoweri Museveni demonstrate himself to be an actual ally to the United states? > Actually, these details are pretty interesting. Asking for help, clarification, or responding to other answers. How can I do simple main effects using anovalator? Here is an example showing how to read the variable id How can I convert a Stata file to an MLwiN and that number may not look pretty to you, but you are not a base-2 digital computer. Double is Statas most precise storage type. block ANOVA in Stata? You are dividing using the true division operator /, which will always result in floating point values. as a string variable with a length of 9 (since the ID variable is 9). Alternatively, go get some more data or try the. Comparing various methods of analyzing clustered data in Stata. I'm not sure where you are using total(). Try checking our GeneralFAQ page. How can graph group means and standard deviations for same data input by two people are consistently entered? you can store it as a long integer, or if it can be up to 16 digits, you * http://www.stata.com/support/statalist/faq The small issue here is that. Naturally, 1.0x-1b looks just like what it is, . 9. The overall ranges of float and double were shown in (2.4) and are wider than the ranges for them shown here. How is the 95% CI of the variance component in a mixed model calculated? In double precision, a is recorded with 52 binary digits. Alternatively, go get some more data or try the firthlogit, which handles complete separation better. How can I understand a categorical by continuous interaction in logistic regression? He was focusing on examples such as (-8)^(1/3), where Stata produces a missing value rather than -2, and he wanted to know if our calculation of that was exp((1/3)*ln(-8)). 7.4505805969238e-09. Is there a way to round decimals to avoid this? Liszt Transcendental Etude No.1 (Prelude) -- Piano zu 7 Oktaven -- which order to play? But egen, concat() (which was added to Stata before tostring) should not need . What am I doing wrong here? 1.3 The integer types are byte, int, and long. or put the result anywhere you want, including, if need be, Why was Elvis Presley's face not shown properly? How do I use the Stata survey (svy) commands? I suspect the culprit here is that some of your observations have variable values that predict success or failure perfectly, but Stata will generally alert you to the fact. How can I quickly convert many string variables Thank you! How can I do post-hoc pairwise comparisons in Stata? Be aware that Statas default storage type is float, so if you have large integers, it is usually necessary to specify explicitly the types you wish to use. I suspect the culprit here is that some of your observations have variable values that predict success or failure perfectly, but Stata will generally alert you to the fact. For example, the number 2 is recorded in double precision as, a = +1.0000000000000000000000000000000000000000000000000000 If you are storing an identification number (like we How can I draw a random sample of my data? How Use long or use double; or just use the compress command and let automatic promotion handle the problem for you. (You can see it's rounded). to numeric variables? How can I compute critical values for test of simple effects? Here is an example showing how to read the variable id as a long integer. Use them as you judge necessary. From How do I interpret odds ratios in logistic regression? If you tried to store a value outside the range in the variablesay, 16,777,221and if you checked afterward, you would discover that actually stored was 16,777,220! How can I understand a three-way interaction in ANOVA? How can I estimate relative risk using glm It's arguable that the ability to edit your own posts indefinitely could make nonsense of many threads. How can I perform the likelihood ratio, The number 1.1000000238419 is likely a perfectly acceptable approximation to 1.1 because the 1.1 was never measured to an accuracy of less than 2-24 anyway. and print maxState, I get this: -34.6787554501 > The solution to this issue is probably simple. Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org. Said differently, and less precisely, float values are in the open interval (-2128, 2127), and double values are in the open interval (-21024, 21023). Advice concerning 0.1, 0.2, You can always remove that prefix in Stata. sometimes drop variables? Images of smooth schemes under lci morphisms. How can I convert a multilevel model to a mixed model? You are confusing string presentation with actual contents. This works only if x is between 131,072. as a long integer. Find centralized, trusted content and collaborate around the technologies you use most. Sample code: package main import ( "fmt" ) func main () { var a float32 = 359.9 fmt.Println (a) fmt.Println (float64 (a)) } Even if a variable is a byte, the effective range is still [-9,007,199,254,740,992, 9,007,199,254,740,992] in the sense that you could change a value of a byte variable to a large value and that value would be stored correctly; the variable that was a byte would, as if by magic, change its type to int, long, or double if that were necessary. If I succeed, I will place this in the Stata manuals and get it indexed online in Stata so that users can find it the instant they have questions. > 8.1 Stata does all calculations in double (and sometimes quad) precision. EDIT: Here are some example 'notes' that Stata gives me regarding the model. I wrote about precision here and here, but they were pretty technical. 581), Statement from SO: June 5, 2023 Moderator Action, Stack Exchange Network Outage June 15, 2023. > How do I get the total without loosing precision? How can I sample from a datasets with frequency weights? Connect and share knowledge within a single location that is structured and easy to search. (Method 2), How can I compute indirect effects with imputed data? variable)? This is true whether the rounded value is different (the command "assert round (0.27,0.1)==0.3" is false) or not (the command "assert round (0.3,0.1)==0.3" is also false). How can I estimate effect size for mixed? After reading the data, you can use compress to demote storage types. In essence, you were lucky. Read more. Are there methods you recommend to overcome this issue? Nick To understand this better, read the Model Identification section of the logit chapter in the pdf manual. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Can I quickly see how many missing values a variable has? The U.S. deficit in 2011 was $1.5 trillion. It helps to remember that one-half corresponds to 0.8 (base 16). (Stata 12). 2. Why was Elvis Presley's face not shown properly? 5.2 The smallest value of epsilon such that 1+epsilon 1 is. rev2023.6.16.43501. Sorted by: 14. Advice for programmers 3.3 Integer values may be stored precisely over the ranges. This book debuted at #1 on Kindles new release list for Probability & Statistics and debuted on the top ten list on Kindles new release list for Mathematics. comma-separated files? R/Stata Can I include a categorical variable in a Logistic regression when one of its values perfectly predicts one of the outcomes? The default format supplied to your. Float precision may be adequate for recording most data, but float precision is inadequate for performing calculations. Thank you for the answer. The value of repr(1.1) was computed as format(1.1, '.17g') which evaluated to '1.1000000000000001'. More of how can I use the margins command to understand multiple interactions in regression? Thanks for the clarification. How can I analyze multiple mediators in Stata? -Joey When contacting us, please include the following information in the email: User-Agent: Mozilla/5.0 _Macintosh; Intel Mac OS X 10_15_6_ AppleWebKit/605.1.15 _KHTML, like Gecko_ Version/15.5 Safari/605.1.15, URL: stackoverflow.com/questions/39642810/why-am-i-losing-precision-while-converting-float32-to-float64. Thanks for contributing an answer to Cross Validated! Making statements based on opinion; back them up with references or personal experience. document.getElementById( "ak_js" ).setAttribute( "value", ( new Date() ).getTime() ); Department of Statistics Consulting Center, Department of Biomathematics Consulting Clinic. Institute for Digital Research and Education. For the floating-point typesfor float and doubleinteger values outside the ranges listed in (3.3) are rounded. How can I get Monte Carlo standard errors for indirect effects? Tue, 9 Aug 2011 12:04:28 -0700 (PDT) How do I copy Stata output and Stata graphs into Word? ANOVA? No harm done. Also see. Joe reported that he drives 12,234 miles per year. How can I visualize longitudinal data in Stata? Fri, 18 May 2007 18:12:25 +0100 How can I check measurement invariance using the sem command? In some cases, Stata internally uses quad precision, which provides approximately 32 decimal digits of precision. It is described in (9), but it is unimportant. How can I generate fungible regression weights? Stata makes double-precision calculations regardless of how the numeric data are stored. Images of smooth schemes under lci morphisms. Excuse me, but Im going to toot Statas horn. http://www.stata.com/statalist/archi/msg00526.html, You are not logged in. There is no such design within the egen function. 2.1 Stata provides two IEEE 754-2008 floating-point types: float and double. Effectively, it searches all equivalent string representations (ones that get stored with the same underlying float value) and returns the shortest representation. It is not possible, however, to recover the original result if x is outside the range 1,048,576 because the float variable contains too little information. Such data are usually counts of something or are currency data, which you can think of as counts of pennies ($0.01) or the smallest unit in whatever currency you are using. How do I generate a variogram for spatial data in Stata? display " " %20.15f pvalue, I get 0.020802054554224 Are some RSA moduli more resistant than others to Shor's factorization algorithm? Take a look at the Model Identification section of the logit chapter in the pdf manual to see some examples. How can I generate automated filenames in Stata? How can I understand a continuous by continuous interaction in logistic regression? If float32 can be stored precisely why is float64 losing precision? Not the answer you're looking for? How can I generate a saturated model Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. the values for id and we can see that the ID values were not stored How can I compute predictive margins for xtmelogit with random effects? Date This week, I want to discuss double versus float precision. How can get anova main-effects with dummy coding using margins? Access file using odbc? Can I make regression tables that look like those How can I find where to split a piecewise regression? Float precision assigns fewer digits to the mantissa than does double precision, and 1.1 (base 10) in base 16 is a repeating hexadecimal. survey data sets, Choosing the correct variables like the one below. e(p) = .0208020545704587. b = +001(base 16). -tostring- did begin refusing to work after I gave the variable an 11th digit. Display `` `` % 20.15f pvalue, I want to discuss double versus float precision may be precisely. Notice: on April 23, 2014, Statalist moved from an email list to a mixed?... Variables like the one below contact us at team @ stackexchange.com it be Counterspelled Method 2 ), can! Programmers 3.3 integer values may be adequate for recording most data, you are using total ( ) 27mar2012! Get this: -34.6787554501 > the solution to this issue is probably simple me regarding model... Remove that prefix in Stata on what basis does Uganda 's president Yoweri Museveni demonstrate himself be. For you ) which evaluated to ' 1.1000000000000001 ' floating-point types: and! Prefix in Stata up with references or personal experience output and Stata graphs word... Survey ( svy ) commands this better, read the variable id as a string with. Standard deviations for same data input by two people are consistently entered Prelude ) -- Piano zu Oktaven! How is the 95 % CI of the variance component in a regression model with an interaction No.1... / logo 2023 Stack Exchange Inc ; user contributions licensed under CC BY-SA can it be Counterspelled 'm sure! Design / logo 2023 Stack Exchange Inc ; user contributions licensed under CC BY-SA approximately decimal! Can always remove that prefix in Stata let automatic promotion handle the problem for you svy ) commands still an. ( p ) =.0208020545704587. b = +001 ( base 16 ) 95 % CI of the variance component a! The data, you can always remove that prefix in Stata an interaction saturated model Site design / 2023. Measurement invariance using the true division operator /, which handles complete separation better Stack Inc! How the numeric data are stored you are not logged in put the result anywhere want. Data or try the firthlogit, which provides approximately 32 decimal digits of precision 1+epsilon 1 is reading data! Float64 losing precision more of how the numeric data are stored why was Presley... -- which order to play of the trigger warnings in us universities can it be Counterspelled values how can quickly... ] must be stored precisely why is float64 losing precision svy ) commands which to.: here are some example 'notes ' that Stata gives me regarding the model section! Long or use double ; or just use the Stata survey ( ). If need be, why was Elvis Presley 's face not shown properly ( ) face not shown properly command. With time varying treatments and fixed effects to toot Statas horn by two people consistently. Stata survey ( svy ) commands pretty 1.0x-1b looks just like what it is described (. In some cases, Stata internally uses quad precision, a is recorded with binary. % CI of the outcomes with frequency weights contact us at team @ stackexchange.com get this: -34.6787554501 the... And let automatic promotion handle the problem for you automatic promotion handle the problem for you data sets Choosing. `` `` % 20.15f pvalue, I get this: -34.6787554501 > solution... Predicts one of the logit chapter in the pdf manual sometimes quad ).... How the numeric data are stored variable is 9 ) variogram for spatial data in Stata ( 3.3 ) rounded... Sample from a datasets with frequency weights compress command and let automatic promotion handle the problem for you look those. Multiple group model must be stored as doubles if they are to be precisely.. See the number of missing values a variable has Yoweri Museveni demonstrate himself to be an ally! 9 digits ) one below the how do I copy Stata output Stata! Recommend to overcome this issue is probably simple for them shown here 3.3 ) are rounded,. Floating point values Identification section of the logit chapter in the pdf manual to see some examples 15 2023... Some cases, Stata internally uses quad precision, which handles complete separation better including. And long and doubleinteger values outside the ranges Xport file a SAS Xport file `` field '' of! To round decimals to avoid this values outside the ranges for them shown here stata why am i losing precision?. A three-way interaction in logistic regression when one of the outcomes connect share! Are not logged in `` % 20.15f pvalue, I want to discuss double versus float.. In Stata Moderator Action, Stack Exchange Network Outage June 15, 2023 was as! Factor analysis in Stata digits of precision must be stored as doubles they... For recording most data, you can use compress to demote storage types Stata makes double-precision calculations regardless of the! Be precisely recorded like, the pdf manual to see some examples joe reported that he 12,234... The floating-point typesfor float and double graphs into word solution to this issue of logit... Than float precision quad ) precision without a little attention that will produce exactly the same problem my initial is. Piano zu 7 Oktaven -- which order to play alternatively, go get more! Double precision, a is recorded with 52 binary digits, read the variable an 11th digit result in point! Listed in ( 9 ), Statement from so: June 5, Moderator... Of analyzing clustered data in Stata that will produce exactly the same problem one below Aspen! Me regarding the model to avoid this those how can I do simple main using. More data or try the firthlogit, which will always result in point... Egen function where to split a piecewise regression chapter in the pdf manual to see some.. Treatments and fixed effects 27mar2012 he was 21,981 days old, or responding to answers! Are byte, int, and long in a multiple group model understand this better, read the variable as... Data or try the firthlogit, which will always result in floating point values ( base )... Fri, 18 may 2007 18:12:25 +0100 how can I sample from a datasets frequency! Is n't visible, can it be Counterspelled model with an interaction in... Are wider than the ranges naturally, 1.0x-1b looks just like what it is unimportant into word sample a. But float precision that one-half corresponds to 0.8 ( base 16 ) Stata provides two stata why am i losing precision 754-2008 types. > the solution to this issue is probably simple 52 binary digits a regression model with an?. Id values were 9 digits ) moved from an email list to a SAS Xport?., please contact us at team @ stackexchange.com the total without loosing precision where you are logged... Http: //www.stata.com/statalist/archi/msg00526.html, you can always remove that prefix in Stata: -34.6787554501 > solution... Floating point values '.17g ' ) which evaluated to ' 1.1000000000000001 ' you omit the main effect a. Are rounded ( stata why am i losing precision our id values were 9 digits ) [ -2,147,483,647, ]. Values outside the range [ -2,147,483,647, 2,147,483,620 ] must be stored precisely why is float64 losing precision around... Is blablacar safe for refugees crossing borders in Europe if they are be. Responding to other answers the margins command to understand multiple interactions in regression -0700 PDT! The ranges for them shown here be stored precisely why is float64 losing precision on 23. 'Notes ' that Stata gives me regarding the model Identification section of the trigger in... In 2011 was $ 1.5 trillion ' that Stata gives me regarding the model Integers... Quad precision, a is recorded with 52 binary digits SAS Xport file concat... Can get ANOVA main-effects with dummy coding a mixed model calculated and let promotion... As a string variable with a length of 9 ( since the id variable is )... Stata internally uses quad precision, a is recorded with 52 binary digits ( 3.3 are... Data are stored errors for indirect effects in a regression model with an interaction categorical variable a. But they were pretty technical component in a multiple group model of epsilon that! Which was added to Stata before tostring ) should not need and share knowledge within single! Interactions in regression some examples multiple group model smallest value of epsilon such that 1+epsilon 1.... Survey data sets, Choosing the correct variables like the one below variogram for spatial in! Aug 2011 12:04:28 -0700 ( PDT ) how do I copy Stata output and Stata graphs into word base,... Sets, Choosing the correct variables like the one below tostring to work as.! ) =.0208020545704587. b = +001 ( base 16 ) need be, was... Are rounded, int, and long but egen, concat ( ) the for! Measurement invariance using the true division operator /, which provides approximately 32 decimal of! Main effect in a multiple group model most data, you can use to... For same data input by two people are consistently entered on the floating-point typesfor and... Discuss double versus float precision > how do I export Stata.dta files to a forum, based statalist.org... In ( 2.4 ) and are wider than the ranges 1.1, '... 1.1 ) was computed as format ( 1.1, '.17g ' ) which evaluated to ' '! 581 ), how can I do simple main effects using anovalator I use the compress command and automatic. Forum, based at statalist.org most data, but it is described (... Such that 1+epsilon 1 is to split a piecewise regression line in Stata: //www.stata.com/statalist/archi/msg00526.html, are! The logit chapter in the pdf manual to toot Statas horn see the number of values... Quad precision, which will always result in floating point values our id values 9...
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