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.
The current version is 1.1. The previous version is here.
If you have any question or comment, please do not hesitate to contact us. Our e-mail address is yamamoto.s.an-a-geo.titech.ac.jp. We also describe the detail of this algorithm in Yamamoto et al. (submitted).

##COMPILE and EXECUTION

Please enter "make" to compile and "./a.out" to execute.

##USAGE

1. 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. OPTIONS

   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	A * r^(B)
   2	power-law with slope = -2	A * r^(-2)
   3	exponential density profile	A * e^(B * r)
   4	post giant impact disk	(Ar + C) * e^(B * r)
   5	user defined	user defined

   -P, --paramter VALUE1,VALUE2,VALUE3...
   change the coefficients of the density profile to VALUE.
   We set A = VALUE1, B = VALUE2, C = VALUE3.

   Examples:

   • Enter "./a.out -d 3 -P 4.0".
     The density profile is set 4e^(-r).

   • Enter "./a.out -d 1 -P 2.0,-1.2".
     The density profile is set 2r^(-1.2).

   • Enter "./a.out -P 2.0,-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.

3. 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.

4. 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 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.

   4.3 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.

   4.4 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.

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

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

   4.7 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).

   4.8 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.

   4.9 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.

   4.10 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.

   4.11 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.

5. 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 1.0,-1.9 -i 60 -O 5.0 ".
     You can get the right-hand side in figure 5 in the article.

   • Enter "./a.out -P 1.0,-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 -P 1.0,-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 -P 4.0,-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.

#Recent Updates Ver.1.1
* Density profile with variable parameters is supported.
* The options to choose parameters of a density profile is unified from -P and -S to -P.
* We get rid of the error that there is an maximum value of the memory of the number of rings.
* Small bugs are fixed.
Ver.1.1.1
* We can compile this code with C++11 and C++03.

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

Copyright 2016- Satoko Yamamoto, Natsuki Hosono, Yoko Funato, Junichiro Makino