Difference between revisions of "Asymptote: Logical Operators and Loops"
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Asymptote uses loops and logical operators that are almost identical to those in C++. Loops are absolutely essential if you want to make diagrams that look like this: | Asymptote uses loops and logical operators that are almost identical to those in C++. Loops are absolutely essential if you want to make diagrams that look like this: | ||
| − | + | <asy> | |
| − | + | import graph; | |
| + | real r=5; | ||
| + | size(r*cm); | ||
| + | picture smiley; | ||
| + | filldraw(smiley,Circle((0,0),1),yellow,black); | ||
| + | fill(smiley,Circle((-.3,.4),.1),black); | ||
| + | fill(smiley,Circle((.3,.4),.1),black); | ||
| + | draw(smiley,Arc((0,0),.5,-140,-40)); | ||
| + | for (int i=0; i<5; ++i) | ||
| + | { | ||
| + | for (int j=0; j<5; ++j) | ||
| + | { | ||
| + | if (floor((i-j)/2)==((i-j)/2)) | ||
| + | { | ||
| + | add(scale(r/10*cm)*smiley,(i,j)); | ||
| + | } | ||
| + | } | ||
| + | } | ||
| + | </asy> | ||
This particular example was produced with the following code: | This particular example was produced with the following code: | ||
| − | + | import graph; | |
real r=5; | real r=5; | ||
size(r*cm); | size(r*cm); | ||
| Line 26: | Line 44: | ||
Above, we created a picture called <tt>smiley</tt> and added it to <tt>currentpicture</tt> many times using a <tt>for</tt> loop, as the indices <math>i</math> and <math>j</math> each ranged from <math>0</math> to <math>4</math>. Basically, the arguments in the parentheses for the first <tt>for</tt> loop first declare <math>i</math> to be an integer and assign to i the value <math>0</math>. Then, if <math>i<5</math>, it executes what is inside the <tt>{}</tt> brackets and when it is finished, it adds <math>1</math> to <math>i</math> (<tt>++i</tt>). This process repeats until the boolean statement <math>i<5</math> has the value false, i.e. 5 times (hence the 5 columns of smileys). The <tt>if</tt> statement is self-explanatory; if <math>\lfloor(i-j)/2\rfloor=(i-j)/2</math> (which checks if <math>i</math> and <math>j</math> have the same parity or not), then the smiley is added, and if not it skips the brackets that follow. | Above, we created a picture called <tt>smiley</tt> and added it to <tt>currentpicture</tt> many times using a <tt>for</tt> loop, as the indices <math>i</math> and <math>j</math> each ranged from <math>0</math> to <math>4</math>. Basically, the arguments in the parentheses for the first <tt>for</tt> loop first declare <math>i</math> to be an integer and assign to i the value <math>0</math>. Then, if <math>i<5</math>, it executes what is inside the <tt>{}</tt> brackets and when it is finished, it adds <math>1</math> to <math>i</math> (<tt>++i</tt>). This process repeats until the boolean statement <math>i<5</math> has the value false, i.e. 5 times (hence the 5 columns of smileys). The <tt>if</tt> statement is self-explanatory; if <math>\lfloor(i-j)/2\rfloor=(i-j)/2</math> (which checks if <math>i</math> and <math>j</math> have the same parity or not), then the smiley is added, and if not it skips the brackets that follow. | ||
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Latest revision as of 13:49, 23 July 2024
Asymptote uses loops and logical operators that are almost identical to those in C++. Loops are absolutely essential if you want to make diagrams that look like this:
![[asy] import graph; real r=5; size(r*cm); picture smiley; filldraw(smiley,Circle((0,0),1),yellow,black); fill(smiley,Circle((-.3,.4),.1),black); fill(smiley,Circle((.3,.4),.1),black); draw(smiley,Arc((0,0),.5,-140,-40)); for (int i=0; i<5; ++i) { for (int j=0; j<5; ++j) { if (floor((i-j)/2)==((i-j)/2)) { add(scale(r/10*cm)*smiley,(i,j)); } } } [/asy]](http://latex.artofproblemsolving.com/9/5/f/95fa81423d78246a35d2cec96696cff8620cf0e7.png)
This particular example was produced with the following code:
import graph;
real r=5;
size(r*cm);
picture smiley;
filldraw(smiley,Circle((0,0),1),yellow,black);
fill(smiley,Circle((-.3,.4),.1),black);
fill(smiley,Circle((.3,.4),.1),black);
draw(smiley,Arc((0,0),.5,-140,-40));
for (int i=0; i<5; ++i)
{
for (int j=0; j<5; ++j)
{
if (floor((i-j)/2)==((i-j)/2))
{
add(scale(r/10*cm)*smiley,(i,j));
}
}
}
Above, we created a picture called smiley and added it to currentpicture many times using a for loop, as the indices 
and 
each ranged from 
to 
. Basically, the arguments in the parentheses for the first for loop first declare to be an integer and assign to i the value . Then, if 
, it executes what is inside the {} brackets and when it is finished, it adds 
to (++i). This process repeats until the boolean statement has the value false, i.e. 5 times (hence the 5 columns of smileys). The if statement is self-explanatory; if 
(which checks if and have the same parity or not), then the smiley is added, and if not it skips the brackets that follow.
