On Monday, February 14, 2011 04:40:24 pm Andreas J. Guelzow wrote:
> On Mon, 2011-02-14 at 13:35 -0500, Daniel P. Dougherty wrote:
> > It used to be in prior versions of Gnumeric that you could select the
> > entire column by clicking on the column header when doing a linear
> > regression. Now when I do this I just get gibberish.
>
The empty cells down to 65536 are clearly not my data and I never asked them
to be part of my data. Frankly, this is simply weird and unexpected behavior
for a spreadsheet to have.
Granted, the click-header-to-select column data idea was always put in
spreadsheets (e.g. Excel) as a hack-ish work-around for the need of
programmers to i) pre-allocate memory for the sheet rows and also ii) because
it was needed to do rapid rendering of the sheet during scrollbar moves (i.e.
paint off screen/double buffering) without flickering. With Gnumeric being an
OOP application, I might argue that its not very nice OOP (data hiding) by
exposing these rather arcane memory allocation internal details to the end
user. Indeed you as the programmer may pre-allocate memory for whatever
number of rows you want--fine. But it's probably a sign of good OOP design
when the casual user isn't aware of what that value is...
But why not also allocate memory for a single integer (not much overhead
there) for the true "row count" of a data set?
Why not use a convention that the number of rows in a data set is equal to the
maximum row index containing at least one non-empty value? Just increment up
the row count as the user enters in data, decrement if they delete/clear, and
if the row count exceeds the memory allocated then allocate more memory -- but
do it silently so the user doesn't need to know about it.
The main points are:
i) The end user shouldn't have to bump up against arcane internal
details
(like the program internally allocates memory for 65536 rows). Such details
certainly shouldn't get them into immediate trouble when doing basic
row/column selections.
ii) The end user is using a spreadsheet because they want point-and-
click functionality. They don't want to have to scroll all the way to the
bottom (possibly large data set) to select/drag back to top row.
iii) Perhaps Gnumeric developers need to come to a consensus on a
special character "." or "NAN" etc to indicate truely missing data versus
empty data (or more generally maybe make the special value user-determined).
iv) OK, why not have a menu item that "Select data block" that gets the
data up to the least non-empty row? Then why not make that method get called
when a user clicks on a column header?
v) If there is no good work-around for this issue one wonders why
column
headers to select the entire column all the way down to 65536 rows even be
enabled feature. When would typical user ever want to do that?? Just
remove that functionality altogether from Gnumeric lest the casual mom and pop
user get themselves into trouble.
P.S.
As an aside I tried to deal with the issue by Edit->Select->"Go to bottom".
Note that "Go to bottom" does stop at the _least_ non-empty row. However, if
there is an empty row followed by data it doesn't get to it.
> Gnumeric now uses the existing sheet functions. As a consequence changes
> in the data are reflected in the output.
> In ancient times, Gnumeric would just calculate everything ones skipping
> any empty fields. Note that that was often not what was desired since a
> single missing value would offset the correspondence between the
> dependent and independent variables.
>
I refer to my point iii) above.... Empty cells within a selection should
probably result in thrown error -- not return 0. Returning 0 was never the
right thing to do. Gnumeric developers should decide on a special character
adopted for truely missing data (or more generally maybe make the special
value user-determined).
iii) Perhaps Gnumeric needs to have a special character "." or "NAN" to
indicate truely missing data versus empty data (or more generally maybe make
the special value user-determined).
> Andreas
>
> > SUMMARY OUTPUT Response Variable: Column 2
> >
> > Regression Statistics
> > Multiple R #VALUE!
> > R^2 #VALUE!
> > Standard Error #VALUE!
> > Adjusted R^2 #VALUE!
> > Observations #VALUE!
> >
> > ANOVA
> >
> > df SS MS F Significance of F
> >
> > Regression 1 #VALUE! #VALUE! #VALUE! #VALUE!
> > Residual #VALUE! #VALUE! #VALUE!
> > Total #VALUE! #VALUE!
> >
> > Coefficients Standard Error t-Statistics p-Value Lower 95%
> > Upper
> >
> > 95%
> > Intercept #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
> > Column 1 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
> >
> > Similar frustrations now also occur when trying to do a histogram.
> > Selecting an entire column without having to drag the entire region
> > worked in previous versions of Gnumeric. Why has this basic
> > functionality disappeared? Is this a bug in the new version?? Based on
> > the output I'm seeing it seems to be a bug and have something to do with
> > 65536 as the maximum number of rows is the Gnumeric sheet getting
> > treated as data (possibly as zeros) even though the cells are empty!!
> > Previous versions were smart enough to detect where in the block of real
> > data ended and the empty cells started.
> >
> >
> > Histogram
> >
> > Column 1
> >
> > from −∞ to below 0.04003886889991 65511
> > from 0.04003886889991 to below 0.14538315034182 3
> > from 0.14538315034182 to below 0.25072743178374 4
> > from 0.25072743178374 to below 0.35607171322565 1
> > from 0.35607171322565 to below 0.46141599466757 5
> > from 0.46141599466757 to below 0.56676027610949 4
> > from 0.56676027610949 to below 0.6721045575514 1
> > from 0.6721045575514 to below 0.77744883899332 2
> > from 0.77744883899332 to below 0.88279312043524 1
> > from 0.88279312043524 to below 0.98813740187715 2
> > from 0.98813740187715 to ∞ 2
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