Xfig/C2/Feedback-diagram-with-Maths/English-timed

Time	Narration
00:00	Welcome to the spoken tutorial on embedding mathematics in Xfig.
00:05	In this tutorial, I shall explain how to create this figure.
00:11	Observe the mathematical expression in the second block.
00:16	You can embed any mathematical expression after learning this tutorial.
00:23	We shall create the figure in the previous slide, starting from this figure, which was created in the spoken tutorial on “Feedback Diagrams through Xfig”.
00:36	You should learn this tutorial before starting the current one.
00:42	Let me now explain, what all you need to learn the material taught in this course.
00:48	I am using Xfig Version 3.2, patch level 5.
00:52	You also need LaTeX and a familiarity with it.
00:56	You also need image cropping software.
01:01	pdfcrop works on Linux and Mac OS X. We will cover it in this tutorial.
01:09	Briss is said to work on Windows also, but not covered in this tutorial.
01:15	Let us go to Xfig.
01:19	Let us choose the File, then Open.
01:26	If we scroll through the list, we will see the file “feedback.fig”, created in the spoken tutorial on “Feedback Diagrams through Xfig”. Let us click it.
01:42	We will see the figure inside this box.
01:45	Let us open it.
01:53	Let us bring it inside.
02:01	Let us also zoom it.
02:05	Using the Save as option on “File”, we will save this figure as maths.
02:20	Let us save it.
02:24	We now have the file "maths.fig".
02:27	Let us select “Edit” and click the text “Plant”.
02:34	Let me take the mouse here. Let me delete this and enter $G(z) = \frac z{z-1}$
02:50	Make sure that the mouse stays within the box while typing.
02:56	The default value for “Flag”' is “Normal” - change it to “Special”.
03:01	Click “Done”.
03:07	As the text is long, it overlaps with other entries.
03:12	Let us move the text outside the box and work with it.
03:23	Let me click here.
03:26	Let me choose Grid Mode.
03:31	Once we are satisfied with any changes that we may want here, we can put it back inside the box.
03:39	Let us save this file.
03:44	Let us export using combined pdf and Latex files.
03:51	File > Export > Combined pdf/LaTeX. Let us Export.
04:03	There is an error message that I get. But let us not worry about this.
04:11	Let me go to the terminal.
04:13	Let me type ls -lrt.
04:21	We get a list of files, with the last one being the most recent.
04:26	The last two files are maths.pdf_t and maths.pdf.
04:33	Let us give the command open maths.pdf.
04:42	Let us bring it inside.
04:45	We can see the block diagram without the mathematical expression.
04:50	Let me close this.
04:52	Let us see maths.pdf_t in emacs editor that I have already opened.
05:01	It is here. Let me open it.
05:14	Please note that you do NOT have to use emacs.
05:17	You can use WHATEVER editor that you are comfortable with.
05:22	You can see that the “picture” environment is used.
05:26	It also makes use of includegraphics and color packages – we need to tell LaTeX to take care of this requirement.
05:41	Let me now open the file maths-bp.tex; I have already created for this tutorial.
05:59	I have used article class.
06:02	I have used color and graphicx packages as these are used in the file pdf_t, the one we saw earlier.
06:15	I want empty pagestyle as I do not want the page number.
06:20	Finally, I want to include the file maths.pdf_t.
06: 27	Let us invoke the command pdflatex maths-bp in the terminal.
06:42	We get the message that the maths-bp.pdf is created.
06:48	Let us open it with the command open maths-bp.pdf.
06:58	We have the file we want. Let me zoom it.
07:07	Now that we know that the mathematical expression is working, let us move the text inside the block.
07:30	Let us save and export. It is already in the required language. Export.
07:38	Let us dismiss this warning.
07:41	Let me compile it again.
07:44	Let us click the pdf browser that has the file.
07: 49	Now you see the mathematical expression inside the box, the way we want.
07:56	Let us now see what happens if we do not choose the Special flag.
08:01	Let me come here.
08:04	Let me edit the text, change the Special Flag to Normal. Done.
08:25	File > Save. Let me export.
08:37	Let me compile. Let me come here.
08:41	The formula is no longer in the form we want.
08:46	Let us change the “Special Flag” back to “Special”.
09:03	Save, Export.
09:12	Recompile. You see that the file is in the form we want.
09:18	Let us now improve the appearance of this formula.
09:22	In this case, the use of 'dfrac' will make the fraction look better.
09:28	In view of this, let us change 'frac' to 'dfrac'.
09:38	Let me click here. Keep the mouse inside the box.
09:43	Put 'd' here. Done. Save, Export.
09:52	Let us compile once again using pdflatex.
10:03	We get the error message “Undefined control sequence” "\dfrac".
10:11	LaTeX complains because the command \dfrac is defined in the package “Amsmath” but we have not included it.
10:21	We need to include it in the file maths-bp.tex'.
10:27	Let us do it. Let us go to emacs.
10:35	Enter “\usepackage{amsmath}”.
10:41	Let us save the file. Let us compile once again. Let me first exit.
10:49	Let me now recompile. Now it compiles. Let us click this.
10:59	We see that the fraction has now come out nicely.
11:03	We have now achieved our objective of learning how to embed mathematical expressions in Xfig.
11:11	It is important to note that Xfig does not interpret the LaTeX commands at all.
11:16	The interpretation is done by the “pdflatex” command.
11:20	The LaTeX commands have to be correct and consistent at the time of compilation.
11:25	We will now explain how to remove the white space around the figure.
11:31	Let me go to the terminal.
11:33	Let me type the command “pdfcrop maths-bp.pdf” - this is the file we created, into “maths-out.pdf”.
11:53	Pdfcrop says, one page written on this file.
11:57	“pdfcrop” takes an input file, trims the space around the figure and writes out the cropped file in the output file.
12:09	“pdfcrop” is already installed in my system.
12:12	If you do not have it, you need to install it first.
12:15	Let us view this output file by the command, “open maths-out.pdf”.
12:29	Let me bring it inside.
12:31	The figure has now become extremely compact.
12:34	The white space that was here has been completely removed.
12:38	We can now insert this into documents.
12:42	Let me close this. Let me close this also. Let me close this also.
12:52	Let me come back to the slides.
12:57	The software “briss” can also be used to crop the white space.
13:01	It is supposed to work on Linux, Mac OS X and also on Windows.
13:08	I have checked its working on Mac OS X. But we will not demonstrate it here.
13:17	We have now come to the end of this tutorial.
13:20	We have an assignment for you. Make the diagram created in this tutorial more symmetric and beautiful.
13:27	Try out different mathematical expressions.
13:30	Try out other options such as flip and rotate, not covered in the spoken tutorial.
13:36	Try to build different diagrams. Explore the library.
13:41	Do an internet search and locate information relevant to Xfig.
13:47	Useful learning material is available at spoken-tutorial.org. It is here.
14:02	The concept of spoken tutorials is explained in "What is a Spoken Tutorial?".
14:09	You may learn LaTeX using the spoken tutorials, available here, which I have downloaded in this tab.
14:19	The tutorial on Mathematical Typesetting explains how to create maths in LaTeX.
14:29	The tutorial on Tables and Figures explains how to place figures of the type created in this tutorial into documents.
14:38	This website has a lot of information, including Xfig tutorials. Come back to the slides.
14:53	Spoken Tutorial is a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT (NMEICT), MHRD, Government of India.
15:03	More information on this mission is available at:spoken-tutorial.org/NMEICT-Intro.
15:12	We welcome your participation and also feedback.
15:16	This is Kannan Moudgalya, signing off. Thanks for joining.

Contributors and Content Editors

Nancyvarkey