I see 5 small purple-ish circles that are arguably the same size.
Yes, there are two .dot files, one with five circles symmetrically arranged, the other with six circles symmetrically arranged too. The difference in the nodes sizes is only between the outputs, although in both dot files the default width attribute is 6, but in fact this attribute does not seem to have an effect on the circle size. I will put the files on the end of this reply, if the forum allows me to do so.
Let me ask some questions:
what version of dot are you using? run dot -V
dot - graphviz version 2.43.0 (0)
what OS are you using (Linux, WIndows, MacOS, …)?
Linux Mint 20
how different are the node sizes - 1 or 2 percent, 50 percent, …
the circles for the 6 nodes graph are twice as big
what program(s) do you use to look at the .png files - MS paint, gimp, a web browser, ??
Xviewer 2.6.2
Have you tried producing a different file format (svg, jpeg, gif, …) If so, were the sizes different?
No, I did not. The pngs are processed further (with LaTeX), so the visual size is not changed by this. Also adding edges to the dot input has no effect on the circles sizes.
will you include your entire input file, the source above is incomplete
5 nodes (there are additional invisible nodes with width=0.0)
strict digraph G {
forcelabels=false
ratio=fill
splines=spline
overlap=scale
size="1.3,1.3"
node [shape=circle,
fixedsize=true,
width=6,
label="",
color="black",
fillcolor="#6666ee",
style="filled,solid"]
edge [arrowsize=15,
penwidth=5]
1 [pos="0,8.1!"];
2 [pos="-9.9,1.1438!"];
4 [pos="-5.5356,-8.6!"];
5 [pos="5.5356,-8.6!"];
3 [pos="9.9,1.1438!"];
t1_2 [width=0.0,pos="-8.8,1.9167!"];
t2_1 [width=0.0,pos="-1.1,7.327!"];
t1_3 [width=0.0,pos="8.8,1.9167!"];
t3_1 [width=0.0,pos="1.1,7.327!"];
t2_4 [width=0.0,pos="-6.02,-7.5173!"];
t4_2 [width=0.0,pos="-9.415,0.0612!"];
t3_5 [width=0.0,pos="6.02,-7.5173!"];
t5_3 [width=0.0,pos="9.415,0.0612!"];
t4_5 [width=0.0,pos="4.3055,-8.6!"];
t5_4 [width=0.0,pos="-4.3055,-8.6!"];
t1_4 [width=0.0,pos="-4.9205,-6.7445!"];
t4_1 [width=0.0,pos="-0.615,6.2445!"];
t1_5 [width=0.0,pos="4.9205,-6.7445!"];
t5_1 [width=0.0,pos="0.615,6.2445!"];
t2_3 [width=0.0,pos="7.7,1.1438!"];
t3_2 [width=0.0,pos="-7.7,1.1438!"];
t4_3 [width=0.0,pos="8.185,0.0612!"];
t3_4 [width=0.0,pos="-3.8205,-7.5174!"];
t5_2 [width=0.0,pos="-8.185,0.0612!"];
t2_5 [width=0.0,pos="3.8205,-7.5174!"];
}
6 nodes (there are additional invisible nodes with width=0.0)
strict digraph G {
forcelabels=false
ratio=fill
splines=spline
overlap=scale
size="1.3,1.3"
node [shape=circle,
fixedsize=true,
width=6,
label="",
color="black",
fillcolor="#6666ee",
style="filled,solid"]
edge [arrowsize=10,
penwidth=5]
1 [pos="0,9!"];
2 [pos="-7.7942,4.5!"];
3 [pos="7.7942,4.5!"];
4 [pos="-7.7942,-4.5!"];
5 [pos="7.7942,-4.5!"];
6 [pos="0,-9!"];
t1_6 [width=0.0,pos="0,-6.75!"];
t6_1 [width=0.0,pos="0,6.75!"];
t1_2 [width=0.0,pos="-5.8457,5.625!"];
t2_1 [width=0.0,pos="-1.9486,7.875!"];
t1_3 [width=0.0,pos="5.8457,5.625!"];
t3_1 [width=0.0,pos="1.9486,7.875!"];
t2_4 [width=0.0,pos="-7.7942,-2.25!"];
t4_2 [width=0.0,pos="-7.7942,2.25!"];
t3_5 [width=0.0,pos="7.7942,-2.25!"];
t5_3 [width=0.0,pos="7.7942,2.25!"];
t6_4 [width=0.0,pos="-5.8457,-5.625!"];
t4_6 [width=0.0,pos="-1.9486,-7.875!"];
t6_5 [width=0.0,pos="5.8457,-5.625!"];
t5_6 [width=0.0,pos="1.9486,-7.875!"];
t2_3 [width=0.0,pos="5.8457,4.5!"];
t3_2 [width=0.0,pos="-5.8457,4.5!"];
t4_5 [width=0.0,pos="5.8457,-4.5!"];
t5_4 [width=0.0,pos="-5.8457,-4.5!"];
t4_3 [width=0.0,pos="5.8457,3.375!"];
t3_4 [width=0.0,pos="-5.8457,-3.375!"];
t5_2 [width=0.0,pos="-5.8457,3.375!"];
t2_5 [width=0.0,pos="5.8457,-3.375!"];
t1_4 [width=0.0,pos="-6.82,-2.8125!"];
t4_1 [width=0.0,pos="-0.9743,7.3125!"];
t1_5 [width=0.0,pos="6.82,-2.8125!"];
t5_1 [width=0.0,pos="0.9743,7.3125!"];
t6_2 [width=0.0,pos="-6.82,2.8125!"];
t2_6 [width=0.0,pos="-0.9743,-7.3125!"];
t6_3 [width=0.0,pos="6.82,2.8125!"];
t3_6 [width=0.0,pos="0.9743,-7.3125!"];
}