Set additional seed photon distribution with exponential law (c86fa72a) · Commits · polarization / slab

README.txt

+74 −54

Original line number	Diff line number	Diff line
		The code computes the polarization degree of radiation from a plane-parallel slab in the diffusion approximation for a pure scattering atmosphere.
		You may use either numerical solution of the coupled system of radiative transfer
		equations as defined in Pomraning (1973) or Monte Carlo method.
		The code computes the spectropolarimetric properties of radiation undergoing electron scattering in a plane-parallel slab.
		One may use either a numerical solution of the coupled system of radiative transfer equations, as defined in Pomraning (1973), or a Monte Carlo method. The latter approach is better suited for computations at high electron temperatures, for which the Klein–Nishina cross-section provides more accurate results.

		======================================================================
		1) Library requirements
		======================================================================

		The following third-party libraries are required for compilation

		@@ -10,10 +11,12 @@ The following third-party libraries are required for compilation
		2) CFITIO library
		3) MPI library

		As these packages may be installed in non-default folders, it is necessary to define some environment variables. These variables tell the compiler and linker where to find the library files and their headers needed to build the code.
		Library headers are files ending in .h that contain definitions needed to use the library in the code.

		As these packages may be installed in non-default folders, it is necessary
		to define some enviroment variables pointing to library headers and shared object.
		These enviroment variables, read by the Makefile at compilation step, are:
		Shared objects (.so) or static libraries (.a) are files containing the compiled library code used by the program at runtime (shared) or at compile-time (static).

		These environment variables are read by the Makefile at the compilation step. The required variables are:

		LIB_CFITSIO
		HEADERS_CFITSIO
		@@ -24,7 +27,19 @@ HEADERS_GSL
		LIB_MPI
		HEADERS_MPI

		Each of them must point to the associated library and to the folder with header files, respectively.

		While you can set these variables in each terminal session, it is recommended to define them once and for all in your shell initialization files:

		For Bash: add the export commands to your ~/.bashrc or ~/.profile

		For C shell (csh/tcsh): add the setenv commands to your ~/.cshrc or ~/.tcshrc

		This way, the variables are automatically set every time you open a new terminal, and you won’t need to define them manually each time.

		======================================================================
		2) Creation of the executable
		======================================================================

		From the local folder where the Makefile is located just type

		@@ -42,16 +57,17 @@ The executable is launched from the shell prompt with a list of parameters, with
		$start_iteration par1=value par2=value etc etc

		======================================================================
		3.1) Numerical solution
		3) Iterative method
		======================================================================

		The parameter selecting this choice of the algorithm is "method=ode"
		The parameter selecting this choice of the iterative algorithm is "method=ode"

		Three locations of the seed photons are possible, and are defined by the parameter "seed=N" where
		Four locations of the seed photons are possible, and are defined by the parameter "seed=N" where

		N=1 photons at the center of the slab
		N=2 photons uniformly distributed across the slab
		N=3 photons at the base of the slab
		N=1 photons at the center
		N=2 photons uniformly distributed
		N=3 photons at the base
		N=4 photons with exponential distribution

		The Thomson optical depth of the slab is defined with parameter "disktau=value"

		@@ -79,71 +95,75 @@ Col2: F(k), namely the total flux emerging from the top of the slab for each ord


		======================================================================
		3.2) Monte Carlo method
		4) Monte Carlo method
		======================================================================

		Here you must select from command line "method=mc"
		While the slab optical depth must be defined as well, for Monte Carlo method the following parameters are required:
		To run the code using the Monte Carlo method, select at at the shell prompt:

		method=mc

		The slab optical depth must also be specified. The following Monte Carlo–specific parameters are required.

		Parameters

		polardisk =y\|n

		which defines if seed photons are initilly polarized (default is no).
		Specifies whether the seed photons are initially polarized. This is valid only for the
		configuration with seed photons at the base of the slab (seed=3).

		albedobase = A

		where A must be defined between 0 and 1. The code assumes an energy-independent albedo at the base of the slab.
		To perform tight comparison of the results with numerical method, you must set A=0.
		Energy-independent albedo at the base of the slab.
		A must be defined between 0 and 1.
		To perform a direct comparison with the iterative method, set A=0.

		nph = N

		the number of photons for each core.
		There are two additional optional parameters to be passed at the prompt, namely the BB seed photons and electron
		temperature, respectively.
		They can be passed simply as
		Number of photons per MPI process.

		The following optional parameters control the BB seed photon and electron temperature, both expressed in keV:

		ktbb=value kte=value

		and their default values is 1 for both cases.
		Default values are ktbb=1 and kte=1.

		To run simulation with single core, you must define at shell prompt
		By default, the results are computed for ten viewing angles. To change this value, use the parameter

		$start_simulation (plus parameter list)
		nstepangles=value

		Tu run multi-core simulation use instead
		Running the simulation

		$mpirun -n Ncores start_simulation (plus parameter list)
		To run a single-core simulation, use:

		The output files are the following:
		start_simulation [parameter list]

		a) spectrum_mc_tauN_seedM_AQ.qdp
		To run a multi-core (MPI) simulation, use:

		Energy spectra at the top of the slab with format:
		mpirun -n Ncores start_simulation [parameter list]

		Col1: E
		Col2: Delta_E
		Col3: I(E)
		Col4-Col25: angle-dependent I(E)
		Output files

		b) integralpolar_mc_tauN_seedM_AQ.qdp
		The code produces the following output files:

		Total, energy-integrated, polarimetric results with format:
		spectrum_mc_tauN_seedM_AQ.qdp

		Col1: u
		Col2: Pdeg (u)
		Col3: Q(u)
		Col4: U(u)
		Col5: Itot(u)/I(1)*1/u
		Energy spectrum at the top of the slab.

		c) energypolar_mc_tauN_seedM_AQ.qdp
		Col 1: photon energy E
		Col 2: energy bin width Delta E
		Col 3: total intensity I(E)
		Col 4–nstepangles : angle-dependent intensity I(E), with u=cos(i) progressively decreasing

		Energy-dependent polarimetric results with column description defined in the file
		integralpolar_mc_tauN_seedM_AQ.qdp

		d) diffusion_mc_tauN_seedM_AQ.qdp
		Energy-integrated spectropolarimetric quantities, with more detailed column description provided at the beginning of the file.

		Col1: number of scatterings k
		Col2: P(k) normalized photon distribution over number of scatterings
		diffusion_mc_tauN_seedM_AQ.qdp

		Photon diffusion statistics.

		Col1: number of scatterings k
		Col2: normalized photon distribution function P(k)

main_program.c

+4 −4

Original line number	Diff line number	Diff line
		#include "globals.h"
		#include "variables.h"
		#include <mpi.h>
		#include <stdio.h>
		#include <common_header.h>
		#include <iteration_functions.h>
		#include <mpi.h>
		#include <stdio.h>

		char* set_filename(char* root, char* tau_char, char* seed_char, char* albedo, char* method);
		char* set_mc_filename(const char* root, double ktbb, double kte, double tau, int seed, double albedo, const char* method);

mc_slab.c

+67 −51

Original line number	Diff line number	Diff line
		@@ -48,7 +48,7 @@ gsl_root_fsolver* s_maxw;

		/==================================================================/

		int slab_mc(int nphot, int seed)
		int slab_mc(int nphot, int seed_distribution)
		{
		int ii;
		int jj;
		@@ -81,6 +81,7 @@ int slab_mc(int nphot, int seed)
		double csi;
		double Pdeg;
		double kn_corr;
		double tau_sampled;

		int naxis1 = 0;
		int naxis2 = 0;
		@@ -102,29 +103,27 @@ int slab_mc(int nphot, int seed)

		/===================================================================================/


		if (getenv("MC_SLAB") == NULL) {
		printf("Please set the enviroment variable MC_SLAB pointing to the folder where it is defined the code executabe\n");
		if (getenv("MC_SLAB") == NULL)
		{
		printf(
		"Please set the enviroment variable MC_SLAB pointing to the folder where it is defined "
		"the code executabe\n");
		exit(EXIT_FAILURE);
		}

		ptr_gb = read_array(stringconcat(getenv("MC_SLAB"), "/temp_random.txt"));


		matrix_gb = stringconcat(getenv("MC_SLAB"), "/gammabeta_lab.fits");
		array_gb = read_matrix(matrix_gb);

		/===================================================================================/

		char* knfile_maxw;
		knfile_maxw =
		stringconcat(getenv("MC_SLAB"), "/S00_lab.fits");

		knfile_maxw = stringconcat(getenv("MC_SLAB"), "/S00_lab.fits");

		matrix_kn = read_matrix(knfile_maxw);

		ptr_kn = read_array(
		stringconcat(getenv("MC_SLAB"), "/energy_temp.txt"));
		ptr_kn = read_array(stringconcat(getenv("MC_SLAB"), "/energy_temp.txt"));

		/===================================================================================/

		@@ -258,6 +257,11 @@ int slab_mc(int nphot, int seed)
		printf("Photon %d\n", ii);
		}

		if (!emin)
		{
		emin = 0.1;
		}

		n_sc = 0;
		E_lab = bb_spec(ktbb);
		E_new_lab = 0;
		@@ -265,21 +269,17 @@ int slab_mc(int nphot, int seed)
		pos[0] = 0;
		pos[1] = 0;

		if (seed == 1)
		if (seed_distribution == SEED_CENTER)
		{
		pos[2] = Hphot / 2;
		cos_theta = 2 * clock_random() - 1;
		}
		else if (seed == 2)
		{
		if (!emin)
		else if (seed_distribution == SEED_UNIFORM)
		{
		emin = 0.1;
		}
		pos[2] = clock_random() * Hphot;
		cos_theta = 2 * clock_random() - 1;
		}
		else
		else if (seed_distribution == SEED_BASE)
		{
		pos[2] = 0;

		@@ -301,6 +301,21 @@ int slab_mc(int nphot, int seed)
		cos_theta = clock_random();
		}
		}
		else if (seed_distribution == SEED_EXP)
		{
		csi = clock_random();

		tau_sampled = log(1 / (1 + csi * (-1 + exp(-disktau))));

		pos[2] = tau_sampled / disktau * Hphot;

		cos_theta = 2 * clock_random() - 1;
		}
		else
		{
		printf("Error: values for seed photon can be 1,2,3,4\n");
		exit(1);
		}

		sin_theta = sqrt(1 - cos_theta * cos_theta);
		phi = 2 * PI * clock_random();
		@@ -653,9 +668,6 @@ void comptonization(double E_lab,
		printf("Error in photon energy in lab frame after scattering: value %5.4f\n", *E_new_lab);
		exit(1);
		}



		}

		/======================================================================/
		@@ -685,17 +697,22 @@ void write_kn_histo(const char* filename)
		{
		// Trova il minimo
		int min_val = histo_kn[0];
		for (int i = 1; i < NBIN_KN; i++) {
		if (histo_kn[i] < min_val) min_val = histo_kn[i];
		for (int i = 1; i < NBIN_KN; i++)
		{
		if (histo_kn[i] < min_val)
		min_val = histo_kn[i];
		}

		if (min_val == 0) {
		fprintf(stderr, "Attenzione: il valore minimo dell'istogramma è 0, normalizzazione impossibile!\n");
		if (min_val == 0)
		{
		fprintf(stderr,
		"Attenzione: il valore minimo dell'istogramma è 0, normalizzazione impossibile!\n");
		exit(EXIT_FAILURE);
		}

		FILE* fp = fopen(filename, "w");
		if (!fp) {
		if (!fp)
		{
		perror("Errore apertura file");
		exit(EXIT_FAILURE);
		}
		@@ -714,4 +731,3 @@ void write_kn_histo(const char* filename)

		fclose(fp);
		}

solve_rte.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -131,7 +131,7 @@ int solve_rte(int k_iter, int seed_distribution, int Nstep_tau)
		else
		{
		printf(
		"Error: please select seed=4 (photons at the base) or seed=2 (uniform distribution)\n");
		"Error: values for seed photon can be 1,2,3,4\n");
		exit(1);
		}
		}