Re: data and function plot causing double assignment

[Daniel J S. <dan...@ie...>]

On 10/04/2011 10:43 AM, pl...@pi... wrote:
> On 10/04/11 17:28, Ethan Merritt wrote:
>> On Tuesday, 04 October 2011, pl...@pi... wrote:
>>> Hi,
>>>
>>> I have found what appears to be a defect in variable assignments in plot.
>>>
>>> gauss0(x)=a0*exp(-(x-pk0)**2/b0)+c0
>>> a1=a0;b1=b0;c1=c0;pk0=-141;
>>> add_one(x)=area0=1;
>>
>> This defines the function add_one(x)
>> to be  add_one(x) =   value of (area0=1)
>>                     = 1
>> So add_one(x) = 1 for all x
>
> Exactly, so why is area still 0 after having been assigned the value 1
> about 512 times?!

Where is the value of area0 used in this set of instructions?  I'm 
wondering if it is used as a value somewhere in the plots what its value 
is when utilized (0 or 1)?

There is some ambiguity here in this statement:

add_one(x)=area0=1;

Does it mean add_one(x)=(area0=1)?  Or (add_one(x)=area0)=1?  It could 
also be that every time there is a set of data for a new plot inside of 
"datafile", area0 is reset to 0.  And possibly that gnuplot is 
programmed so that area0 is set to zero, THEN check whether there is 
more data to plot.  (And one could argue that is unintended, but again 
it has to be defined in documentation to remove ambiguity.)  Could you 
explore things a little more by using the value of area0 inside the 
plots and figure out from the plots what value of area0 is being used?

Dan


> I reiterate that if I remove the function plot I do get areas=1 after
> plotting. This indicates that plot is re-executing area0=0 after the
> second data plot and before plotting the function.
>
> /Peter.
>
>
>> Any later changes to the value of area0 are not relevant.
>>
>> 	Ethan
>>
>>> plot  area0=0\
>>> , datafile using 1:(add_one($2)) w l\
>>> , datafile using 1:(($2)) w l\
>>> , gauss0(x) tit 'fitted peak0'\
>>>
>>> print "area0=",area0;
>>>
>>> I was expecting this to do the assignment area0=0 once and once only
>>> before any of the lines were plotted.
>>>
>>> It is only assigned once for the datafile plots but adding the function
>>> plot causes this snippet to print a value of zero , not one.
>>>
>>> I am inferring that using a mix of data and function plots is causing
>>> the initial assignment to be done twice.  Bug or feature?
>>>
>>> best regards, Peter.
>>>
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>>
>>
>
>
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> definitive record of customers, application performance, security
> threats, fraudulent activity and more. Splunk takes this data and makes
> sense of it. Business sense. IT sense. Common sense.
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Dan Sebald
email: daniel(DOT)sebald(AT)ieee(DOT)org
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