I have a variable of type float. Xcode displays it using scientific notation (i.e. 3.37626e+07). I'm trying to get it to display using dot notation (i.e. 33762616.00).
I've tried every format provided by lldb, but none displays the float using decimals. I read other posts and watched the WWDC2012 session 415 (as suggested here), but I must be too close the forest to see the trees. Any help would be greatly appreciated!
Try adding a custom data formatter in your ~/.lldbinit file for type float. e.g.
Process 13204 stopped
* thread #1: tid = 0xb6f8d, 0x0000000100000f33 a.out`main + 35 at a.c:5, stop reason = step over
#0: 0x0000000100000f33 a.out`main + 35 at a.c:5
2 int main ()
3 {
4 float f = 33762616.0;
-> 5 printf ("%f\n", f);
6 }
(lldb) p f
(float) $0 = 3.37626e+07
(lldb) type summ add -v -o "return '%f' % valobj.GetData().GetFloat(lldb.SBError(), 0)" float
(lldb) p f
(float) $1 = 33762616.000000
(lldb)
The default set of formatters provided by lldb can't do this, but dropping into Python allows you a lot of flexibility.
Related
I have read a lot about the pain of replicate the easy robust option from STATA to R to use robust standard errors. I replicated following approaches: StackExchange and Economic Theory Blog. They work but the problem I face is, if I want to print my results using the stargazer function (this prints the .tex code for Latex files).
Here is the illustration to my problem:
reg1 <-lm(rev~id + source + listed + country , data=data2_rev)
stargazer(reg1)
This prints the R output as .tex code (non-robust SE) If i want to use robust SE, i can do it with the sandwich package as follow:
vcov <- vcovHC(reg1, "HC1")
if I now use stargazer(vcov) only the output of the vcovHC function is printed and not the regression output itself.
With the package lmtest() it is possible to print at least the estimator, but not the observations, R2, adj. R2, Residual, Residual St.Error and the F-Statistics.
lmtest::coeftest(reg1, vcov. = sandwich::vcovHC(reg1, type = 'HC1'))
This gives the following output:
t test of coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) -2.54923 6.85521 -0.3719 0.710611
id 0.39634 0.12376 3.2026 0.001722 **
source 1.48164 4.20183 0.3526 0.724960
country -4.00398 4.00256 -1.0004 0.319041
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
How can I add or get an output with the following parameters as well?
Residual standard error: 17.43 on 127 degrees of freedom
Multiple R-squared: 0.09676, Adjusted R-squared: 0.07543
F-statistic: 4.535 on 3 and 127 DF, p-value: 0.00469
Did anybody face the same problem and can help me out?
How can I use robust standard errors in the lm function and apply the stargazer function?
You already calculated robust standard errors, and there's an easy way to include it in the stargazeroutput:
library("sandwich")
library("plm")
library("stargazer")
data("Produc", package = "plm")
# Regression
model <- plm(log(gsp) ~ log(pcap) + log(pc) + log(emp) + unemp,
data = Produc,
index = c("state","year"),
method="pooling")
# Adjust standard errors
cov1 <- vcovHC(model, type = "HC1")
robust_se <- sqrt(diag(cov1))
# Stargazer output (with and without RSE)
stargazer(model, model, type = "text",
se = list(NULL, robust_se))
Solution found here: https://www.jakeruss.com/cheatsheets/stargazer/#robust-standard-errors-replicating-statas-robust-option
Update I'm not so much into F-Tests. People are discussing those issues, e.g. https://stats.stackexchange.com/questions/93787/f-test-formula-under-robust-standard-error
When you follow http://www3.grips.ac.jp/~yamanota/Lecture_Note_9_Heteroskedasticity
"A heteroskedasticity-robust t statistic can be obtained by dividing an OSL estimator by its robust standard error (for zero null hypotheses). The usual F-statistic, however, is invalid. Instead, we need to use the heteroskedasticity-robust Wald statistic."
and use a Wald statistic here?
This is a fairly simple solution using coeftest:
reg1 <-lm(rev~id + source + listed + country , data=data2_rev)
cl_robust <- coeftest(reg1, vcov = vcovCL, type = "HC1", cluster = ~
country)
se_robust <- cl_robust[, 2]
stargazer(reg1, reg1, cl_robust, se = list(NULL, se_robust, NULL))
Note that I only included cl_robust in the output as a verification that the results are identical.
Hello i am encountering this error message in a Haskell program and i do not know where is the loop coming from.There are almost no IO methods so that i can hook myself to them and print the partial result in the terminal.
I start with a file , i read it and then there are only pure methods.How can i debug this ?
Is there a way to attach to methods or create a helper that can do the following:
Having a method method::a->b how can i somehow wrap it in a iomethod::(a->b)->IO (a->b) to be able to test in in GHCI (i want to insert some putStrLn-s etc ?
P.S My data suffer transformations IO a(->b->c->d->......)->IO x and i do not know how to debug the part that is in the parathesis (that is the code that contains the pure methods)
Types and typeclass definitions and implementations
data TCPFile=Rfile (Maybe Readme) | Dfile Samples | Empty
data Header=Header { ftype::Char}
newtype Samples=Samples{values::[Maybe Double]}deriving(Show)
data Readme=Readme{ maxClients::Int, minClients::Int,stepClients::Int,maxDelay::Int,minDelay::Int,stepDelay::Int}deriving(Show)
data FileData=FileData{ header::Header,rawContent::Text}
(>>?)::Maybe a->(a->Maybe b)->Maybe b
(Just t) >>? f=f t
Nothing >>? _=Nothing
class TextEncode a where
fromText::Text-> a
getHeader::TCPFile->Header
getHeader (Rfile _ ) = Header { ftype='r'}
getHeader (Dfile _ )= Header{ftype='d'}
getHeader _ = Header {ftype='e'}
instance Show TCPFile where
show (Rfile t)="Rfile " ++"{"++content++"}" where
content=case t of
Nothing->""
Just c -> show c
show (Dfile c)="Dfile " ++"{"++show c ++ "}"
instance TextEncode Samples where
fromText text=Samples (map (readMaybe.unpack) cols) where
cols=splitOn (pack ",") text
instance TextEncode Readme where
fromText txt =let len= length dat
dat= case len of
6 ->Prelude.take 6 .readData $ txt
_ ->[0,0,0,0,0,0] in
Readme{maxClients=Prelude.head dat,minClients=dat!!1,stepClients=dat!!2,maxDelay=dat!!3,minDelay=dat!!4,stepDelay=dat!!5} where
instance TextEncode TCPFile where
fromText = textToFile
Main
module Main where
import Data.Text(Text,pack,unpack)
import Data.Text.IO(readFile,writeFile)
import TCPFile(TCPFile)
main::IO()
main=do
dat<-readTcpFile "test.txt"
print dat
readTcpFile::FilePath->IO TCPFile
readTcpFile path =fromText <$> Data.Text.IO.readFile path
textToFile::Text->TCPFile
textToFile input=case readHeader input >>? (\h -> Just (FileData h input)) >>? makeFile of
Just r -> r
Nothing ->Empty
readHeader::Text->Maybe Header
readHeader txt=case Data.Text.head txt of
'r' ->Just (Header{ ftype='r'})
'd' ->Just (Header {ftype ='d'})
_ -> Nothing
makeFile::FileData->Maybe TCPFile
makeFile fd= case ftype.header $ fd of
'r'->Just (Rfile (Just (fromText . rawContent $ fd)))
'd'->Just (Dfile (fromText . rawContent $ fd))
_ ->Nothing
readData::Text->[Int]
readData =catMaybes . maybeValues where
maybeValues=mvalues.split.filterText "{}"
#all the methods under this line are used in the above method
mvalues::[Text]->[Maybe Int]
mvalues arr=map (\x->(readMaybe::String->Maybe Int).unpack $ x) arr
split::Text->[Text]
split =splitOn (pack ",")
filterText::[Char]->Text->Text
filterText chars tx=Data.Text.filter (\x -> not (x `elem` chars)) tx
I want first to clean the Text from given characters , in our case }{ then split it by ,.After the text is split by commas i want to parse them, and create either a Rfile which contains 6 integers , either a Dfile (datafile) which contains any given number of integers.
Input
I have a file with the following content: r,1.22,3.45,6.66,5.55,6.33,2.32} and i am running runghc main 2>err.hs
Expected Output : Rfile (Just (Readme 1.22 3.45 6.66 5.55 6.33 2.32))
In the TextEncode Readme instance, len and dat depend on each other:
instance TextEncode Readme where
fromText txt =let len= length dat
dat= case len of
To debug this kind of thing, other than staring at the code, one thing you can do is compile with -prof -fprof-auto -rtsopts, and run your program with the cmd line options +RTS -xc. This should print a trace when the <<loop>> exception is raised (or if the program loops instead, when you kill it (Ctrl+C)). See the GHC manual https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/runtime_control.html#rts-flag--xc
As Li-yao Xia said part of the problem is the infinite recursion, but if you tried the following code, then the problem still remains.
instance TextEncode Readme where
fromText txt =let len= length [1,2,3,4,5,6] --dat
dat= case len of
The second issue is that the file contains decimal numbers but all the conversion function are expecting Maybe Int, changing the definitions of the following functions should give the expected results, on the other hand probably the correct fix is that the file should have integers and not decimal numbers.
readData::Text->[Double]
--readData xs = [1,2,3,4,5,6,6]
readData =catMaybes . maybeValues where
maybeValues = mvalues . split . filterText "{}"
--all the methods under this line are used in the above method
mvalues::[Text]->[Maybe Double]
mvalues arr=map (\x->(readMaybe::String->Maybe Double).unpack $ x) arr
data Readme=Readme{ maxClients::Double, minClients::Double,stepClients::Double,maxDelay::Double,minDelay::Double,stepDelay::Double}deriving(Show)
I'm trying to implement a PID controller following http://en.wikipedia.org/wiki/PID_controller
The mechanism I try to control works as follows:
1. I have an input variable which I can control. Typical values would be 0.5...10.
2. I have an output value which I measure daily. My goal for the output is roughly at the same range.
The two variables have strong correlation - when the process parameter goes up, the output generally goes up, but there's quite a bit of noise.
I'm following the implementation here:
http://code.activestate.com/recipes/577231-discrete-pid-controller/
Now the PID seems like it is correlated with the error term, not the measured level of output. So my guess is that I am not supposed to use it as-is for the process variable, but rather as some correction to the current value? How is that supposed to work exactly?
For example, if we take Kp=1, Ki=Kd=0, The process (input) variable is 4, the current output level is 3 and my target is a value of 2, I get the following:
error = 2-3 = -1
PID = -1
Then I should set the process variable to -1? or 4-1=3?
You need to think in terms of the PID controller correcting a manipulated variable (MV) for errors, and that you need to use an I term to get to an on-target steady-state result. The I term is how the PID retains and applies memory of the prior behavior of the system.
If you are thinking in terms of the output of the controller being changes in the MV, it is more of a 'velocity form' PID, and the memory of prior errors and behavior is integrated and accumulated in the prior MV setting.
From your example, it seems like a manipulated value of -1 is not feasible and that you would like the controller to suggest a value like 3 to get a process output (PV) of 2. For a PID controller to make use of "The process (input) variable is 4,..." (MV in my terms) Ki must be non-zero, and if the system was at steady-state, whatever was accumulated in the integral (sum_e=sum(e)) would precisely equal 4/Ki, so:
Kp= Ki = 1 ; Kd =0
error = SV - PV = 2 - 3 = -1
sum_e = sum_e + error = 4/Ki -1
MV = PID = -1(Kp) + (4/Ki -1)Ki = -1Kp + 4 - 1*Ki = -1 +4 -1 = 2
If you used a slower Ki than 1, it would smooth out the noise more and not adjust the MV so quickly:
Ki = 0.1 ;
MV = PID = -1(Kp) + (4/Ki -1)Ki = -1Kp + 4 - 1*Ki = -1 +4 -0.1 = 2.9
At steady state at target (PV = SV), sum_e * Ki should produce the steady-state MV:
PV = SV
error = SV - PV = 0
Kp * error = 0
MV = 3 = PID = 0 * Kp + Ki * sum_e
A nice way to understand the PID controller is to put units on everything and think of Kp, Ki, Kd as conversions of the process error, accumulated error*timeUnit, and rate-of-change of error/timeUnit into terms of the manipulated variable, and that the controlled system converts the controller's manipulated variable into units of output.
I am new to Haskell. Previously I have programmed in Python and Java. When I am debugging some code I have a habit of littering it with print statements in the middle of code. However doing so in Haskell will change semantics, and I will have to change my function signatures to those with IO stuff. How do Haskellers deal with this? I might be missing something obvious. Please enlighten.
Other answers link the official doco and the Haskell wiki but if you've made it to this answer let's assume you bounced off those for whatever reason. The wikibook also has an example using Fibonacci which I found more accessible. This is a deliberately basic example which might hopefully help.
Let's say we start with this very simple function, which for important business reasons, adds "bob" to a string, then reverses it.
bobreverse x = reverse ("bob" ++ x)
Output in GHCI:
> bobreverse "jill"
"llijbob"
We don't see how this could possibly be going wrong, but something near it is, so we add debug.
import Debug.Trace
bobreverse x = trace ("DEBUG: bobreverse" ++ show x) (reverse ("bob" ++ x))
Output:
> bobreverse "jill"
"DEBUG: bobreverse "jill"
llijbob"
We are using show just to ensure x is converted to a string correctly before output. We also added some parenthesis to make sure the arguments were grouped correctly.
In summary, the trace function is a decorator which prints the first argument and returns the second. It looks like a pure function, so you don't need to bring IO or other signatures into the functions to use it. It does this by cheating, which is explained further in the linked documentation above, if you are curious.
Read this. You can use Debug.Trace.trace in place of print statements.
I was able to create a dual personality IO / ST monad typeclass, which will print debug statements when a monadic computation is typed as IO, them when it's typed as ST. Demonstration and code here: Haskell -- dual personality IO / ST monad? .
Of course Debug.Trace is more of a swiss army knife, especially when wrapped with a useful special case,
trace2 :: Show a => [Char] -> a -> a
trace2 name x = trace (name ++ ": " ++ show x) x
which can be used like (trace2 "first arg" 3) + 4
edit
You can make this even fancier if you want source locations
{-# LANGUAGE TemplateHaskell #-}
import Language.Haskell.TH
import Language.Haskell.TH.Syntax as TH
import Debug.Trace
withLocation :: Q Exp -> Q Exp
withLocation f = do
let error = locationString =<< location
appE f error
where
locationString :: Loc -> Q Exp
locationString loc = do
litE $ stringL $ formatLoc loc
formatLoc :: Loc -> String
formatLoc loc = let file = loc_filename loc
(line, col) = loc_start loc
in concat [file, ":", show line, ":", show col]
trace3' (loc :: String) msg x =
trace2 ('[' : loc ++ "] " ++ msg) x
trace3 = withLocation [| trace3' |]
then, in a separate file [from the definition above], you can write
{-# LANGUAGE TemplateHaskell #-}
tr3 x = $trace3 "hello" x
and test it out
> tr3 4
[MyFile.hs:2:9] hello: 4
You can use Debug.Trace for that.
I really liked Dons short blog about it:
https://donsbot.wordpress.com/2007/11/14/no-more-exceptions-debugging-haskell-code-with-ghci/
In short: use ghci, example with a program with code called HsColour.hs
$ ghci HsColour.hs
*Main> :set -fbreak-on-exception
*Main> :set args "source.hs"
Now run your program with tracing on, and GHCi will stop your program at the call to error:
*Main> :trace main
Stopped at (exception thrown)
Ok, good. We had an exception… Let’s just back up a bit and see where we are. Watch now as we travel backwards in time through our program, using the (bizarre, I know) “:back” command:
[(exception thrown)] *Main> :back
Logged breakpoint at Language/Haskell/HsColour/Classify.hs:(19,0)-(31,46)
_result :: [String]
This tells us that immediately before hitting error, we were in the file Language/Haskell/HsColour/Classify.hs, at line 19. We’re in pretty good shape now. Let’s see where exactly:
[-1: Language/Haskell/HsColour/Classify.hs:(19,0)-(31,46)] *Main> :list
18 chunk :: String -> [String]
vv
19 chunk [] = head []
20 chunk ('\r':s) = chunk s -- get rid of DOS newline stuff
21 chunk ('\n':s) = "\n": chunk s
^^
I want to see what functions are called in my user-space C99 program and in what order. Also, which parameters are given.
Can I do this with DTrace?
E.g. for program
int g(int a, int b) { puts("I'm g"); }
int f(int a, int b) { g(5+a,b);g(8+b,a);}
int main() {f(5,2);f(5,3);}
I wand see a text file with:
main(1,{"./a.out"})
f(5,2);
g(10,2);
puts("I'm g");
g(10,5);
puts("I'm g");
f(5,3);
g(10,3);
puts("I'm g");
g(11,5);
puts("I'm g");
I want not to modify my source and the program is really huge - 9 thousand of functions.
I have all sources; I have a program with debug info compiled into it, and gdb is able to print function parameters in backtrace.
Is the task solvable with DTrace?
My OS is one of BSD, Linux, MacOS, Solaris. I prefer Linux, but I can use any of listed OS.
Here's how you can do it with DTrace:
script='pid$target:a.out::entry,pid$target:a.out::return { trace(arg1); }'
dtrace -F -n "$script" -c ./a.out
The output of this command is like as follows on FreeBSD 14.0-CURRENT:
dtrace: description 'pid$target:a.out::entry,pid$target:a.out::return ' matched 17 probes
I'm g
I'm g
I'm g
I'm g
dtrace: pid 39275 has exited
CPU FUNCTION
3 -> _start 34361917680
3 -> handle_static_init 140737488341872
3 <- handle_static_init 2108000
3 -> main 140737488341872
3 -> f 2
3 -> g 2
3 <- g 32767
3 -> g 5
3 <- g 32767
3 <- f 0
3 -> f 3
3 -> g 3
3 <- g 32767
3 -> g 5
3 <- g 32767
3 <- f 0
3 <- main 0
3 -> __do_global_dtors_aux 140737488351184
3 <- __do_global_dtors_aux 0
The annoying thing is that I've not found a way to print all the function arguments (see How do you print an associative array in DTrace?). A hacky workaround is to add trace(arg2), trace(arg3), etc. The problem is that for nonexistent arguments there will be garbage printed out.
Yes, you can do this with dtrace. But you probably will never be able to do it on linux. I've tried multiple versions of the linux port of dtrace and it's never done what I wanted. In fact, it once caused a CPU panic. Download the dtrace toolkit from http://www.brendangregg.com/dtrace.html. Then set your PATH accordingly. Then execute this:
dtruss -a yourprogram args...
Your question is exceedingly likely to be misguided. For any non-trivial program, printing the sequense of all function calls executed with their parameters will result in multi-MB or even multi-GB output, that you will not be able to make any sense of (too much detail for a human to understand).
That said, I don't believe you can achieve what you want with dtrace.
You might begin by using GCC -finstrument-functions flag, which would easily allow you to print function addresses on entry/exit to every function. You can then trivialy convert addresses into function names with addr2line. This gives you what you asked for (except parameters).
If the result doesn't prove to be too much detail, you can set a breakpoint on every function in GDB (with rb . command), and attach continue command to every breakpoint. This will result in a steady stream of breakpoints being hit (with parameters), but the execution will likely be at least 100 to 1000 times slower.