I am not able to understand what is the logic behind these lines:
COMPUTE temp = RESULT - 1.843E19.
IF temp IS LESS THAN 1.0E16 THEN
Data definition:
000330 01 VAR1 COMP-1 VALUE 3.4E38. // 3.4 x 10 ^ 38
Here are those lines in context (the sub-program returns a square root):
MOVE VAR1 TO PARM1.
CALL "SQUAREROOT_ROUTINE" USING
BY REFERENCE PARM1,
BY REFERENCE RESULT.
COMPUTE temp = RESULT - 1.843E19.
IF temp IS LESS THAN 1.0E16 THEN
DISPLAY "OK"
ELSE
DISPLAY "False"
END-IF.
These lines are just trying to test if the result returned by the SQUAREROOT_ROUTINE is correct. Since the program is using float-values and rather large numbers this might look a bit complicated. Let's just do the math:
You start with 3.4E38, the squareroot is 1.84390889...E19.
By subtracting 1.843E19 (i.e. the approximate result) and comparing the difference against 1.0E16 the program is testing whether the result is between 1.843E19 and 1.843E19+1.0E16 = 1.844E19.
Not that this test would not catch an error if the result from SQUAREROOT_ROUTINE was too low instead of too high. To catch both types of wrong results you should compare the absolute value of the difference against the tolerance.
You might ask "Why make things so complicated"? The thing is that float-values usually are not exact and depending on the used precision you will get sightly different results due to rounding-errors.
well the logic itself is very straight forward, you are subtracting 1.843*(10^19) from the result you get from the SQUAREROOT_ROUTINE and putting that value in the variable called temp and then If the value of temp is less than 1.0*(10^16) you are going to print a line out to the SYSOUT that says "OK", otherwise you are going to print out "False" (if the value was equal to or greater than).
If you mean the logic as to why this code exists, you will need to talk to the author of the code, but it looks like a debugging display that was left in the program.
Related
I'm attempting to write a script in LUA for the Minecraft mod ComputerCraft. It's supposed to send a turtle down, mine a hole, and place ladders before returning to the surface. I'm trying to make an error display when the turtle doesn't have enough ladders, but I'm receiving an error that prevents it from running. "mineDown :18: attempt to compare string with number expected, got string."
-- This gets the user to tell the turtle how far to dig down
print('How far down should I go?')
distDown = io.read()
distMoved = 0
ladders = turtle.getItemCount(13)
-- Check if the number of ladders is less than the distance needed to move. If so, returns error.
turtle.select(13)
if ladders < distDown then
error('Not enough ladders!')
end
The error means that ladders is number and distDown is a string. You need to convert them to the same type. For example to convert ladders to a string use tostring or distDown to a number use tonumber:
if ladders < tonumber(distDown) then
I have a file with more than 250 variables and more than 100 cases. Some of these variables have an error in decimal dot (20445.12 should be 2.044512).
I want to modify programatically these data, I found a possible way in a Visual Basic editor provided by SPSS (I show you a screen shot below), but I have an absolute lack of knowledge.
How can I select a range of cells in this language?
How can I store the cell once modified its data?
--- EDITED NEW DATA ----
Thank you for your fast reply.
The problem now its the number of digits that number has. For example, error data could have the following format:
Case A) 43998 (five digits) ---> 4.3998 as correct value.
Case B) 4399 (four digits) ---> 4.3990 as correct value, but parsed as 0.4399 because 0 has been removed when file was created.
Is there any way, like:
IF (NUM < 10000) THEN NUM = NUM / 1000 ELSE NUM = NUM / 10000
Or something like IF (Number_of_digits(NUM)) THEN ...
Thank you.
there's no need for VB script, go this way:
open a syntax window, paste the following code:
do repeat vr=var1 var2 var3 var4.
compute vr=vr/10000.
end repeat.
save outfile="filepath\My corrected data.sav".
exe.
Replace var1 var2 var3 var4 with the names of the actual variables you need to change. For variables that are contiguous in the file you may use var1 to var4.
Replace vr=vr/10000 with whatever mathematical calculation you would like to use to correct the data.
Replace "filepath\My corrected data.sav" with your path and file name.
WARNING: this syntax will change the data in your file. You should make sure to create a backup of your original in addition to saving the corrected data to a new file.
I'm working in a project that uses the IBM SPSS but I had some problems to set a dummy variable(binary variable).The process to get the variable is following : Consider an any variable(width for example), to get the dummy variable, we need
to sort this variable in the decreasing way; The next step is make a somatory of the cases until a limit, the cases before the limit receive the value 1 in the dummy variable the other values receive 0.
Your explanation is rather vague. And the critical value you give in the printscreen should be 2.009 in stead of 20.09?
But I think you mean the following.
When using syntax, use:
compute newdummyvariable eq (ABr gt 2.009477106).
To check if it's okay:
fre newdummyvariable.
UPDATE:
In order to compute a dummy based on the cumulative sum, the answer is as follows:
If your critical value is predetermined, the fastest way is to sort in decending order, and to use the command create with csum() to compute an extra variable which I called ABr_cumul. This one, you use to compute the newdummyvariable. As follows:
sort cases by ABr (d).
create ABr_cumul = csum(VAR00001).
compute newdummyvariable = (ABr_cumul le 20.094771061766488).
fre newdummyvariable.
the dummy comes from the sum of all cases, after decreasing order raqueados when cases of a variable representing 50% of the variable t0tal, these cases receive 1 and the other 0 ...
This question already has answers here:
Lua for loop reduce i? Weird behavior [duplicate]
(3 answers)
Closed 7 years ago.
im trying this in lua:
for i = 1, 10,1 do
print(i)
i = i+2
end
I would expect the following output:
1,4,7,10
However, it seems like i is getting not affected, so it gives me:
1,2,3,4,5,6,7,8,9,10
Can someone tell my a bit about the background concept and what is the right way to modify the counter variable?
As Colonel Thirty Two said, there is no way to modify a loop variable in Lua. Or rather more to the point, the loop counter in Lua is hidden from you. The variable i in your case is merely a copy of the counter's current value. So changing it does nothing; it will be overwritten by the actual hidden counter every time the loop cycles.
When you write a for loop in Lua, it always means exactly what it says. This is good, since it makes it abundantly clear when you're doing looping over a fixed sequence (whether a count or a set of data) and when you're doing something more complicated.
for is for fixed loops; if you want dynamic looping, you must use a while loop. That way, the reader of the code is aware that looping is not fixed; that it's under your control.
When using a Numeric for loop, you can change the increment by the third value, in your example you set it to 1.
To see what I mean:
for i = 1,10,3 do
print(i)
end
However this isn't always a practical solution, because often times you'll only want to modify the loop variable under specific conditions. When you wish to do this, you can use a while loop (or if you want your code to run at least once, a repeat loop):
local i = 1
while i < 10 do
print(i)
i = i + 1
end
Using a while loop you have full control over the condition, and any variables (be they global or upvalues).
All answers / comments so far only suggested while loops; here's two more ways of working around this problem:
If you always have the same step size, which just isn't 1, you can explicitly give the step size as in for i =start,end,stepdo … end, e.g. for i = 1, 10, 3 do … or for i = 10, 1, -1 do …. If you need varying step sizes, that won't work.
A "problem" with while-loops is that you always have to manually increment your counter and forgetting this in a sub-branch easily leads to infinite loops. I've seen the following pattern a few times:
local diff = 0
for i = 1, n do
i = i+diff
if i > n then break end
-- code here
-- and to change i for the next round, do something like
if some_condition then
diff = diff + 1 -- skip 1 forward
end
end
This way, you cannot forget incrementing i, and you still have the adjusted i available in your code. The deltas are also kept in a separate variable, so scanning this for bugs is relatively easy. (i autoincrements so must work, any assignment to i below the loop body's first line is an error, check whether you are/n't assigning diff, check branches, …)
I work with SPSS and have difficulty finding/generating a syntax for counting cases.
I have about 120 cases and five variables. I need to know the count /proportion of cases where just one, more than one, or all of the cases have a value of 1 (dichotomous variable). Then I need to compute a new variable that shows the number / proportion of cases which include all of the aforementioned cases (also dichotomous).
For example case number one: var1=1, var2=1, var3=1, var4=0, var5=0 --> newvariable=1.
Case number two: var1=0, var2=0, var3=0, var4=0, var5=0 --> newvariable=1.
And so on...
Can anybody help me with a syntax?
Help would much appreciated!
Here we can use the sum of the variables to determine your conditions. So using a scratch variable that is the sum, we can see if it is equal to 1, more than 1 or 5 in your example.
compute #sum = SUM(var1 to var5).
compute just_one = (#sum = 1).
compute more_one = (#sum > 1).
compute all_one = (#sum = 5).
Similarly, all_one could be computed using the ANY command to evaluate if any zeroes exist, i.e. compute all_one = ANY(0,var1 to var5).. These code snippets assume that var1 to var5 are contiguous in the data frame, if not they just need to be replaced with var1,var2,var3,var4,var5 in all given instances.
You could read up on the logical function ANY in the Command Syntax Reference manual, if you negated a test for ANY with "0", then that is effectively a test for all "1"s. Use of the COUNT command would be another approach.