2 basic calc questions

2 basic calc questions

[Ryan Moszynski]

1) how do I get calc to display answers as a decimal with all trailing
digits until there are repeated zeros?

for example, I would like to display the result of
.5 * .09^2
as
0.00405

2) how do i get the calc trail window to scroll automatically so that
the bottom of the calc trail, with most recent calculation is always
shown?

thanks,

Ryan M

-- 
He felt that his whole life was some kind of dream and he sometimes
wondered whose it was and whether they were enjoying it. - Douglas
Adams

Re: 2 basic calc questions

[tomas]

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On Fri, Jan 20, 2023 at 06:06:47PM -0500, Ryan Moszynski wrote:
> 1) how do I get calc to display answers as a decimal with all trailing
> digits until there are repeated zeros?

What if there are infinitely many trailing digits?

Cheers
-- 
t

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Re: 2 basic calc questions

[H. Dieter Wilhelm]

Ryan Moszynski <ryan.moszynski@gmail.com> writes:

> 2) how do i get the calc trail window to scroll automatically so that
> the bottom of the calc trail, with most recent calculation is always
> shown?

I think that's a, more or less, recent regression of Calc (emacs-28?).
(As a workaround you might type "t ]".)

If nobody suggest a possible customisation for the trail buffer, we
should do a report-emacs-bug.

    Dieter

-- 
Best wishes
H. Dieter Wilhelm
Zwingenberg, Germany

Re: 2 basic calc questions

[Michael Heerdegen]

Ryan Moszynski <ryan.moszynski@gmail.com> writes:

> 1) how do I get calc to display answers as a decimal with all trailing
> digits until there are repeated zeros?
>
> for example, I would like to display the result of
> .5 * .09^2
> as
> 0.00405

The commands behind the "display" prefix d, e.g. M-5 d n, as explained in

  (info "(calc) Modes Tutorial")

are not what you want?


Michael.

Re: 2 basic calc questions

[H. Dieter Wilhelm]

Ryan Moszynski <ryan.moszynski@gmail.com> writes:

>
> 2) how do i get the calc trail window to scroll automatically so that
> the bottom of the calc trail, with most recent calculation is always
> shown?

Did you check this when doing emacs -Q? (I have something in my init
file that also inhibits proper srolling.)

-- 
Best wishes
H. Dieter Wilhelm
Zwingenberg, Germany

Re: 2 basic calc questions

[Michael Heerdegen]

"H. Dieter Wilhelm" <dieter@duenenhof-wilhelm.de> writes:

> > 2) how do i get the calc trail window to scroll automatically so that
> > the bottom of the calc trail, with most recent calculation is always
> > shown?
>
> Did you check this when doing emacs -Q? (I have something in my init
> file that also inhibits proper srolling.)

One thing that inhibits proper scrolling is text-scale-mode.
problematic also in the normal Calc window.

Michael.

Re: 2 basic calc questions

[H. Dieter Wilhelm]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> "H. Dieter Wilhelm" <dieter@duenenhof-wilhelm.de> writes:
>
>> > 2) how do i get the calc trail window to scroll automatically so that
>> > the bottom of the calc trail, with most recent calculation is always
>> > shown?
>>
>> Did you check this when doing emacs -Q? (I have something in my init
>> file that also inhibits proper srolling.)
>
> One thing that inhibits proper scrolling is text-scale-mode.
> problematic also in the normal Calc window.

Hmm, it seems to me that C-x C-+, which I'm using regularly, also
affects 'text-scale-mode'.  Thank you, I'll check this..

     Dieter
-- 
Best wishes
H. Dieter Wilhelm
Zwingenberg, Germany

Re: 2 basic calc questions

[Michael Heerdegen]

"H. Dieter Wilhelm" <dieter@duenenhof-wilhelm.de> writes:

> Hmm, it seems to me that C-x C-+, which I'm using regularly, also
> affects 'text-scale-mode'.  Thank you, I'll check this..

Affects... it controls `text-scale-mode'!

BTW, do you only see problems with the trail - or also with the stack
window?


Thx,

Michael.

Re: 2 basic calc questions

[H. Dieter Wilhelm]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> "H. Dieter Wilhelm" <dieter@duenenhof-wilhelm.de> writes:
>
>> Hmm, it seems to me that C-x C-+, which I'm using regularly, also
>> affects 'text-scale-mode'.  Thank you, I'll check this..
>
> Affects... it controls `text-scale-mode'!

I see, thanks.  (I'm using it regularly on all kind of Org buffers,
rarely for the calc buffers..)

> BTW, do you only see problems with the trail - or also with the stack
> window?

So far only for the trail buffer!

   Dieter

-- 
Best wishes
H. Dieter Wilhelm
Zwingenberg, Germany

Re: 2 basic calc questions

[Ryan Moszynski]

> What if there are infinitely many trailing digits?

I would like to see all significant digits after the decimal, up to
some sort of maximum number. I don't want to worry about losing
significant digits, and I don't want to see a ton of trailing zero's.

 I don't understand why 'accuracy' isn't something that can be set,
and I don't understand why there's not a way that i've found to tell
calc to: show me all the digit's that are meaningful, and in the case
that there are many meaningful digits, just show me the first 10 or
so.

https://www.gnu.org/software/emacs/manual/html_node/calc/Precision.html

"The accuracy is simply the number of digits after the decimal point
(again not counting trailing zeros). In Calc you control the
precision, not the accuracy of computations. If you were to set the
accuracy instead, then calculations like ‘exp(100)’ would generate
many more digits than you would typically need, while ‘exp(-100)’
would probably round to zero! In Calc, both these computations give
you exactly 12 (or the requested number of) significant digits."