Arnab's Graph Explorer 3.00a

Graph Explorer was previously known as Graph Paper. But it is more of a graph plotter and explorer than a virtual graph paper. Also people used to mistake that it was a graph paper printer from the title. So the title was changed to Graph Explorer from version 2.10a. I also put my name as a part of the title hoping to eliminate title-clashing with other softwares, once and for all. It has gone a long way since I lost the source code and rebuilt it. It has improved a lot thanks to your imaginations. I still sincerely hope that you will send me any doubts/suggestions/opinions (or just a 'thank you' ;) about this program! And also if you do mail me, I'd be happy to learn how you have come across this program.

Walkthrough with Graph Explorer

Graph Explorer can only draw graphs of functions. It cannot draw relations, like x2+y2=1. Having said this, let me show how the program can be used.

Basics

Working with Graph Explorer is very very easy! Press Ctrl+F to display the Function window. Here you are supposed to describe y as a function of x. Erase whatever is already here, and type y=1/(1+x@). Here x@ is actually shorthand for x*x (or x2). Click on Draw. You will get a bell shaped curve. You can click your mouse inside the graph window and drag to slide the virtual graph paper and explore more of the function.

Now change the function to y=1/(1+x^3). The ^ operator is power, so that x^y is xy and x*x is same as x^2 (or x@). The new graph will have a discontinuity at x = -1 and you will not be able to see much of it in the default sized window. Either you will have to change the window size, or you must scale the graph down by holding Shift and dragging the mouse left. You will notice the thinner gradings (which were evenly space at a distance of 0.1 units) will disappear when they become dense enough. Now each thin line is 1 unit apart.

Interactive Scaling

You can scale up the graph also, by holding down Shift and dragging right. Plot the function y=x*sin(1/x). Now scale the graph up to view the function closer at (0,0). At maximum zoom, the thinner lines are spaced at a distance of 0.0001 unit. To go back to normal zoom by pressing Ctrl+R and press Ctrl+T to open the Plot Settings dialog. Type 100 at both X Scale and Y Scale and click Set. The values you type here are the number of pixels that the program takes as 1 unit. As you can see, you can achieve uneven scaling (i.e. different scales for x and y) from this dialog box. It is also possible to do this more naturally, drag while pressing Ctrl. Also note that you can cancel any interactive change if you click the right mouse button before leaving the left.

The following scaling modes are implemented:

Uniform Scaling	Shift
Free Scaling	Ctrl
Independent Scaling	Alt
X Scaling	Alt+Shift
Y Scaling	Alt+Ctrl
Constant Area Scaling	Ctrl+Shift

Variables

Now clear the function and type a=x*x, and in the next line type y=(a-1)/(a+1). This will draw (as you have probably anticipated) the graph of y=(x2-1)/(x2+1). Likewise you can define as many variables you want to. You can also change a variable as a function of itself. For example, putting x=10^x in the beginning or putting y=Log10(y) in the end will respectively convert x or y into log-scale. Before they are defined, all variables take the value of Zero.

Functions

You can define your own functions too. For example, set the function named f1 to be y=x/2+sin(x). Now add another function, and set it to be y=-f1(2*x)/2. You will notice a kind of 'reflection' of the original function having more 'frequency' appear. Remember functions take the variable x as input, and must put the return value into y. If you need more than one inputs or outputs you can use global variables (i.e. variables starting with an underscore). You can refer to functions which have 'nice' names only. For example you can't refer to any functions whose name has a blank, or starts with a number, or has a special character, even though functions are allowed to have such names. And I have deliberately written the code in such a manner that you can redefine most of the builtin functions (e.g. sin), but I hope you will use this freedom carefully!

You can put multiple equations in a single line by separating them with semicolons (;). Also anything after a double slash (//) in a line is ignored - to let you put comments. One last piece of information - Graph Explorer does not distinguish between uppercase and lowercase. There are some other things in Graph Explorer, most of which are pretty self explanatory.

Inbuilt Functions

There are many more built in functions like 'sin' in Graph Explorer. Here is a complete list.

Some Tips

• Do not write y=2x which produces error, instead use y=2*x.
• To square, use '@' instead of using '^2', which is slower. Example: y=(x@/2)@+1 instead of y=(x^2/2)^2+1.
• Rightclick on the list of functions to add more functions.
• Press F2 when a function in the list of the funcitions is selected to change the name of the function.
• There are some predefined constants: _Pi, _e, and _dx (which is actually the amount x increases per one pixel).
• Any variable starting with an underscore ( _ ) is global, i.e. defining its value in any one (preferably the first) function will define it for all other functions too.
• To change x coordinate to log-scale add 'x=10^x' (i.e. the inverse transformation) to the beginning of your function. To change y into log-scale add 'y=Log10(y)' to the end of your function. Similar methods will allow you to change into any scale.

That's all! Please feel free to send comments and suggestions to me.

Version History