DISKS

DISKS is a program to generate concentric distribution of equal-mass particles to realize disks of a user-specified density distribution by placing particles in concentric rings. All you have to do is choice of a density profile and parameters of a disk.
If you have any question or comment, please do not hesitate to contact us. Our e-mail address is yamamoto.s.an@geo.titech.ac.jp. We also describe the detail of this algorithm in Yamamoto et al. (in submitted).

##USAGE

SYNOPSIS

Please enter "make" only once and "./a.out".

DESCRIPTION

In default, the parameters are given below
density profile = r^(-1)
inner edge = 1.0
outer edge = 4.0
cut edge = 1.0
(start point to place particles)
the number of a ring at cut edge = 20
the number of particles in a ring = 40
(it is used with only slope is -2 at cut edge.)
tolerance = 10^(-8)

2.1 Density Profile options:

-d, --denstype TYPE
create the density profile specified by TYPE.

TYPE	density profile type	function
1	power-law except slope = -2	S * r^(P)
2	power-law with slope = -2	S * r^(-2)
3	exponential density profile	S * e^(P * r)
4	post giant impact disk	S * (r - 1) * e^(P * r)
5	user defined	user defined

-P, --powernumber VALUE
change the parameter P to VALUE.

-S, --coefficient VALUE
change the parameter S to VALUE.

Examples:

Enter "./a.out -d 3 -S 4.0".
The density profile is set 4e^(-r).
Enter "./a.out -d 1 -S 2.0 -P -1.2".
The density profile is set 2r^(-1.2).
Enter "./a.out -S 2.0 -P -1.2".
The density profile is set 2r^(-1.2).

If you want to choose user defined density profile, please edit "userdefined.h". Some examples are written in the file.

2.2 Disk Parameters options:

-I, --inneredge VALUE
change the position of the inner edge to VALUE.
It must be a non-negative number or 0.

-O, --outeredge VALUE
change the position of the outer edge to VALUE.
It must be larger than 0.

-C, --cutedge VALUE
change the position of the cut edge to VALUE.
The cut edge must be between the inner edge and the outer edge.

-i, --icut VALUE
change the number of a ring at the cut edge to VALUE.
It must be integer greater than 0.

-n, --npzero VALUE
change the number of particles in a ring to VALUE.
It must be integer greater than 0 and is used with only slope = -2 at the cut edge.

Examples:

Enter "./a.out -I 2.0 -O 5.0 -C 3.0 -i 30".
A disk, whose range is r = [2.0:5.0], is generated.
Placement of particles is stated at r = 3.0.
The number of a ring at the cut edge is set to 30.
Enter "./a.out -O 5.0 -i 30".
A disk, whose range is r = [1.0:5.0], is generated.
Placement of particles is stated at r = 1.0.
The number of a ring at the cut edge is set to 30.

2.3 Other options:

-o --output FILE
write result to FILE instead of standard output [filename].

Example:

Enter "./a.out -o test.dat".

-t --tolerance VALUE
change the value of the tolerance to VALUE.

-p --outputdens
calculate the density of particles.
Note that there are large error near the inner edge and the outer edge because of low-order of SPH approximation. In addition, it takes N^2 times, where N is the number of particles.

-h --help
display help.

Examples:

Enter "./a.out -d 2 -i 10 -O 5.0 -n 40 ".
You can get the left-hand side in figure 5 in the article.
Enter "./a.out -P -1.9 -i 60 -O 5.0 ".
You can get the right-hand side in figure 5 in the article.
Enter "./a.out -P -1.45 ".
You can get the right-hand side in figure 6 in the article.
Enter "./a.out -d 3 -i 15 ".
You can get the left-hand side in figure 9 in the article.
Enter "./a.out -d 4 -I 2.0 -C 2.0 -i 10 ".
You can get the right-hand side in figure 9 in the article.
Enter "./a.out -d 3 -S 1.0 -P -0.5 -I 0.0 -O 3.0 -C 0.1 -i 1 -o test.dat".
A disk, whose density profile is e^(-0.5r) and range is r = [0.0:3.0], is generated.
Placement of particles is stated at r = 0.1.
The number of a ring at the cut edge is set to 1.
The output file is "./test.dat".
Enter "./a.out -S 4.0 -P -3.0 -I 2.0 -C 2.0 -i 50".
A disk, whose density profile is 4r^(-3.0) and range is r = [2.0:4.0], is generated.
Placement of particles is stated at r = 2.0.
The number of a ring at the cut edge is set to 50.
Enter "./a.out -d 2 -n 40".
A disk, whose density profile is r^(-2) and range is r = [1.0:4.0], is generated.
Placement of particles is stated at r = 1.0.
The number of a ring at the cut edge is set to 20.
The number of particles for each ring is set to 40.

Output Data

The parameters of particles are outputted. From left to right, the values mean
(particle id, x-coordinate, y-coordinate, radius, density).
If you do not choose the option -p, values of density are set to 0.
Errors

If there are errors in this program, an error message is outputted.

4.1 Error: The number of iterations for deriving parameters of the ring is over 'number'.
We put a ceiling to the number of iterations for calculating the parameters of particles for the degrees of freedom of a tolerace.
If you want to change the maximum number of iterations, please change the parameter max_iteration (l.30 in main.cc).

4.2 Error: Please increase the parameter of max_number_of_ring (l.12 in main.cc).
There is an maximum value of the memory of the number of rings. If the error is outputted, please change the parameter of max_number_of_ring (l.12 in main.cc). We are going to update the specification as soon as possible.

4.3 Error: Please increase the number of a ring at the cut edge or decrease the value of the cut edge by changing the parameter of the option -i or -C.
The optimal number of particles at i-th ring becomes negative. It can be avoided to change the parameter of the option -i or -C.

4.4 Error: The number of particles in a ring is zero. Please change the parameter of the option -n.
For the slope = -2 at the cut edge, the number of a ring is given by the option -n and the parameter must be integer greater than 0.

4.5 Error: Please change the cut edge or the inner edge by changing the parameter of the option -C or -I.
The mass is non-number or negative. It can be avoided to change the parameter of option -C or -I.

4.6 Error: Fail to open 'file name'. Please change the filename by the option -f.
The file-name is invalid. Please change file name.

4.7 Error: Invalid option 'option'.
You choose an invalid option. But it dose not effect the program.

4.8 Error: Invalid type of the density profile. Please change the parameter of the option -d.
You choose an invalid type of a density profile. The type of density profile is 1, 2, 3, 4 or 5 (see 2.1).

4.9 Error: Invalid value of the inner edge. Please change the parameter of the option -I.
You choose an invalid value of the inner edge. The value must be non-negative or 0.

4.10 Error: Invalid value of the outer edge. Please change the parameter of the option -O.
You choose an invalid value of the outer edge. The value must be larger than 0.

4.11 Error: Invalid value of the cut edge. Please change the parameter of the option -C.
You choose an invalid value of the cut edge. The cut edge must be between the inner edge and the outer edge.

4.12 Error: Invalid number of a ring at the cut edge. Please change the parameter of the option -i.
You choose an invalid number of a ring at the cut edge. It must be integer greater than 0.

##Author Satoko Yamamoto, Natsuki Hosono, Yoko Funato, Junichiro Makino

NatsukiHosono/DISKS

DISKS