This example illustrates setting line styles and adding text.
The final image looks best as a pgf picture included
in a LaTeX document, as then you can use maths fonts with
subscripts.
Select the ||,
and create a rectangle, as shown in Figure 11.16.
Figure 11.16: Artificial Neuron Example--Adding a Rectangle
Select the ||,
and create a circle, as shown in Figure 11.17.
Figure 11.17: Artificial Neuron Example--Adding a Circle
To make the logistic function symbol, select the
||, and do a
single segment (Figure 11.18(a)).
Then use the
|| tool to
adjust the curvature, as shown in Figure 11.18(b).
(If you have enabled the grid lock, you may find it easier to
disable it while you are editing the curvature control points.)
(a)
(b)
Figure 11.18: Artificial Neuron Example--creating a sigmoidal
curve: (a) adding an open curve
segment; (b) edit segment to adjust curvature.
Next set the current line style to have an end
arrow. Note that lines with end markers look best with a butt cap
style, so this should also be set. This can be done as follows:
Use the Settings->Styles... menu item to display the
current styles dialog box. Select the tab labelled
Line Style to display the line style panel.
Select Butt from the labelled Cap Style (see
Figure 11.19).
Next select the button labelled Select... located
on the same row as End Marker to
open the end marker dialog box (illustrated in
Figure 11.20). Select the radio button labelled
Use Marker. This will enable the marker
chooser panel. Select the tab labelled
Arrows and select
Pointed 60. Select Okay
to close the end marker dialog box and select
Okay to close the styles dialog box.
Figure 11.19: Artificial Neuron Example--Setting the Current Line
Style
Use Settings->Styles... to open the current styles
selector, and set the font family to "Serif" and press
Okay. Select the
||, and add
in the text, as illustrated in Figure 11.22.
Figure 11.22: Artificial Neuron Example--Adding Text
If you want to include your image into a LaTeX document as
a pgfpicture environment, it would look better if you
put the text into maths mode, and use subscripts. To do this
first select the , and then select
Edit->Text->Edit text.... This will open up the
edit text dialog box. Click on the Different button, and
enter the text as it should be in the LaTeX file
(Figure 11.23.) Do this for each .
In addition, select all of the text on the left ("x1", "x2"
and "xn") and use the
Edit->Text->Font Style->All Styles... dialog box to
change the horizontal anchor parameter
to Right. (Note that
you will not see any difference to the image in Jpgfdraw.)
Figure 11.23: Artificial Neuron Example--Editing Text
Select the || and start a
text area in the rectangle. I want to use a capital sigma to
indicate a summation, and as I don't know the magic combination of
characters to access that symbol, I used the
Insert Symbol dialog box. To do this, either use the
popup menu and select Insert Symbol...,
or press the Ins key. The required symbol can now be
selected from the dialog box (illustrated in
Figure 11.24).
Figure 11.24: Artificial Neuron Example--Insert Symbol Dialog
Box
Use the Edit->Text->Font Style->All Styles... to change the
font size to 25 and change both the anchor settings to
Centre, see Figure 11.25.
(You don't need to change the anchor settings if you have the
|| setting
enabled, as it will change when you justify the in step 9.)
Figure 11.25: Artificial Neuron Example--Setting the Font Style
If you want to export your image into a LaTeX document, you will
need to set the LaTeX equivalent text to $\Sigma$. As
before, this is done by selecting the and using the
Edit->Text->Edit text... menu item to open the
Edit Text dialog box
(Figure 11.26(b)).
The Sigma would
look much better if it was
centred inside the rectangle. To do this
|| the
Sigma and the rectangle, then || them
either by clicking on the group objects button or by using the
Transform->Group menu item. Then select the
Transform->Justify->Centre menu item, and then
the Transform->Justify->Middle menu item. The
should now be centred inside the
rectangle (Figure 11.27).
To include the image inside a LaTeX document, save the image
to a LaTeX file using the File->Export... menu item,
and then include it in your document (assuming the file was called
neuron.tex):
(Remember to use the pgf package.) The image will appear
in the LaTeX document as illustrated in Figure 11.28.
(For best results use either PDFLaTeX or
LaTeX and dvips as some dvi viewers may not be able
to interpret the pgf specials.)
Figure 11.28: Artificial Neuron Example--Image as it Appears in a
LaTeX Document