[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[seul-edu] Fw: gnuplot and GNU Emacs Calc
Here's a long message I received in response to the request in
the latest Linux in education report for tutorials on the use of
gnuplot:
On Tue, 2 Jan 2001, Robert J. Chassell wrote:
> GNU Emacs Calc mode runs gnuplot. You can create output for
> an ascii
> terminal or for an X window or for a printer.
>
> The Calc manual has good lots of documentation. For example,
>
> The easiest graphics command is `g f' (`calc-graph-fast').
>
>
> This command takes two vectors of equal length from the
> stack.
> The vector at the top of the stack represents the "y"
> values of
> the various data points. The vector in the second-to-top
> position
> represents the corresponding "x" values.
>
> This command runs GNUPLOT (if it has not already been
> started by
> previous graphing commands) and displays the set of data
> points.
> The points will be connected by lines, and there will also
> be some
> kind of symbol to indicate the points themselves.
>
> I use gnuplot and Calc mode to compute least squares linear
> regressions and then plot the actual data and the best fit
> curve.
>
> Emacs Calc is a standard part of Emacs, but because of its
> size is not
> in most standard Emacs distributions (at 832 kilobytes, people
> used to
> think it huge... :)
>
> You can get it via ftp from
>
> alpha.gnu.org:/gnu/calc
>
> Mirror sites, and an Emacs expression so you can see the
> directory
> using ange-ftp:
>
> (dired "/ftp@aeneas.mit.edu:/pub/gnu" nil)
> (dired "/ftp@ftp.cs.columbia.edu:/archives/gnu/prep"
> nil)
> (dired "/ftp@ftp.digex.net:/pub/gnu/" nil)
>
>
> Besides graphing, arithmetic, matrixes operations, and so on,
> Calc
> simplifies algebraic expressions, does least squares linear
> regressions, transcendentals, differentiation, and
> integration.
>
> The Calc manual is in Texinfo format. This means you can read
> it on
> line in Emacs, or in HTML on a Web site, or print it out as a
> (rather
> big) nicely typeset book.
>
> (Actually, the manual is in two parts: a tutorial and a
> reference
> manual; you can print it as either one or as two books.)
>
>
> Here are some notes
>
>
> How to show mathematical expressions in different formats
> =========================================================
>
>
> The `d N' (`calc-normal-language') command selects the usual
> notation for Calc formulas
>
> `d B' (`calc-big-language')
>
> `d C' (`calc-c-language')
>
> `d T' (`calc-tex-language')
>
> For example:
>
> (a+1)/b + c^2
>
> to
> a + 1 2
> ----- + c
> b
>
> and to
>
> (a + 1) / b + c ** 2
>
> in place of `sqrt((a+1)/b + c^2)'.
>
>
> Here is example for solving a quadratic equation of the form
> for the
> value of x, given a, b, and c:
>
> ax^2 + bx + c = 0
>
> These following are all the same, but interconverted from one
> to
> another display mode using Emacs Calc.
>
>
> Emacs Calc `Big' mode:
>
> ___________
> | 2
> (-b) +/- \| b - 4 ac
> x = ----------------------
> 2 a
>
>
> Emacs Calc `Normal' mode:
>
> x = (-b +/- sqrt(b^2 - 4 ac) / 2 a)
>
> Emacs Calc `TeX' mode:
>
> x = {-b \pm \sqrt{b^2 - 4 ac} \over 2 a}
>
>
> Working in an email buffer:
> ---------------------------
>
> Suppose you have this expression in your mail buffer:
>
> 0.6666-(4/15)*sqrt(10*pi^2*r^3/(D^2*G*m*epsilon)-1)
>
> In the mail buffer in which I am composing the message, I type
> `M-# d'
> (i.e., Press alt key and # key at the same time, then press
> the d key)
>
> This duplicates the expression. I then type:
>
> M-# e
>
> to turn on Embedded Calc mode, and then type `m f' to keep the
> fraction from being automatically converted to a float, and
> then type
> `d B', which converts the duplicated expression to this:
>
> ____________________
> | 2 3
> 4 | 10 pi r
> 0.6666 - -- | -------------- - 1
> 15 | 2
> \| D G m epsilon
>
> which I find easier to read. (Also, I may type `d o' to
> specify what
> format to use for fractions, and `m s' to prevent early
> evaluation of
> symbolic forms. Just type them to see what happens.)
>
> Actually, after typing `m f' and `m B' the first time, each
> time I
> duplicate an expression like:
>
> (Q/(x*(1-e)^2))^(1/4)
>
> the duplicate is inserted in my email buffer in `big' mode.
>
> Q 1/4
> (----------)
> 2
> x*(1 - e)
>
> (This is not as easy to read as the preceding expression, but
> is easier than
> the `flat' format.)
>
>
>
>
> How to operate on each of a column of numbers
> =============================================
>
>
> 21 April 1993,
> Edward J. Hartnett asks:
>
> ... what would I do
> to perform a simple mathematical manipulation on each,
> specifically I
> want to multiply each element by 174 and pop another vector
> back into
> my original document, so if I had:
>
> 1
> 2
> 3
>
> I would be able to get
>
> 1 174
> 2 348
> 3 522
>
>
> Use the Calc mapping and yank commands; see File: calc.info,
> Node: Mapping, and Node: Yanking Into Buffers, for more
> information.
>
> You can record the sequence of commands in a keyboard macro;
> or use
> the `generate.el' library from the archives to create a elisp
> function
> that does the job, based on your keystrokes. The advantage of
> an
> elisp function is that you can edit it easily.
>
>
> Commands Comments
>
>
> M-# g grab the column as a vector and insert in
> *Calc* buffer
>
> 174 insert number you want to multiply each
> element by
>
> V M * Vector action, Mapped over each element,
> Multiplication
>
> v u unpack vector so each element is on the stack
> separately
> See File: calc.info, Node: Packing and
> Unpacking
>
> This results in separate items in the stack, each of which is
> an
> element of the original column, multiplied by 174. The *Calc*
> buffer
> looks like this:
>
> 3: 174
> 2: 348
> 1: 522
>
>
> You can yank the elements out of the *Calc* buffer in two ways
> (with
> my calc-version 2.02).
>
> If point in your working buffer is in the left most (i.e.,
> first
> column) `C-u 3 M-# y' yanks out the top three elements of the
> stack,
> producing a column like this:
>
> 174
> 348
> 522
>
> On the other hand, if point in your working buffer is not in
> the left
> most (i.e., not in the first column) `C-u 3 M-# y' yanks out
> the top
> three elements of the stack, and the line numbers, too:
>
> 3: 174
> 2: 348
> 1: 522
>
> I don't understand why this is so and my documentation does
> not
> explain this. I don't know how this works in other versions
> of Calc.
> In any case, you want the column without the line numbers.
>
> You can copy your column to where ever you want it using Emacs
> rectangle commands.
>
> I have bound `kill-rectangle' to `C-c k' and `yank-rectangle'
> to
> `yank-rectangle', which makes it very easy to move a rectangle
> from
> one place to another. Place point and mark around the column,
> type
> `M-x kill-rectangle', move mark to the upper left hand corner
> of where
> you want to insert the rectangle and type `M-x
> yank-rectangle'.
>
>
>
>
> Two other useful commands:
>
> V [ turn off brackets in vector in *Calc* buffer
> See File: calc.info, Node: Vector and
> Matrix Formats
>
> V , turn off commas in vector in *Calc* buffer
>
>
>
>
>
>
> How to show "fixed-point" notation with two digits after the
> decimal point
>
===========================================================================
>
>
> type
>
> M-2 d f
>
> To show "normal" notation with three significant digits,
> type
>
> M-3 d n
>
> "scientific notation" d s
>
> "engineering notation" d e
>
>
> To set precision:
>
> p 12
>
> 12 is the default precision. Display format does not
> effect precision.
>
> To measure angles in degrees: m d To measure angles in
> radians: m r
>
> To convert degrees to radians: c r To convert radians to
> degrees: c d
>
> To convert to "hexadecimal", or "base-16" form,
> type:
>
> d r 16 <RET>
>
> Use `d r 2 <RET>' to see it in binary
> Use `d r 10<RET>' to see it in base 10
>
>
>
> Best wishes.
>
> --
> Robert J. Chassell bob@rattlesnake.com
> Rattlesnake Enterprises
> http://www.rattlesnake.com
>
--
Doug Loss The art of medicine consists of amusing the
dloss@suscom.net patient while nature cures the disease.
(570) 326-3987 Voltaire