Merge pull request #71 from ldvries/development

Adding features for Manakov equation

Author: wahls

.gitignore

@@ -6,7 +6,7 @@
 !Doxyfile
 
 # Unignore subdirectories
-#!/examples/
+!/examples/
 !/include/
 !/include/private/
 !/include/3rd_party/eiscor/
@@ -16,7 +16,24 @@
 !/src/private/
 !/src/3rd_party/eiscor/
 !/src/3rd_party/kiss_fft/
-#!/test/
+!/test/
+!/test/fnft__akns_fscatter/
+!/test/fnft__fft_wrapper/
+!/test/fnft__kdv_finvscatter/
+!/test/fnft__kdv_scatter/
+!/test/fnft_kdvv/
+!/test/fnft__manakov_fscatter/
+!/test/fnft__manakov_scatter/
+!/test/fnft_manakovv/
+!/test/fnft__misc/
+!/test/fnft__nse_finvscatter/
+!/test/fnft_nsep/
+!/test/fnft__nse_scatter/
+!/test/fnft_nsev/
+!/test/fnft_nsev_inverse/
+!/test/fnft__poly/
+!/test/fnft_version_test/
+!/test/fnft_version_test.c/
 
 # Ignore MacOS hidden files in subdirectories
 /**/*.DS_Store
@@ -36,6 +53,7 @@
 !/**/*.h
 !/**/*.h.in
 !/**/*.m
+!/**/*.inc
 
 # Explicitly reignore fnft_config.h, which is generated by cmake
 /include/fnft_config.h

CMakeLists.txt

@@ -223,4 +223,4 @@ if (WITH_MATLAB)
       # -DMEX_DOUBLE_HANDLE avoids the new complex interleaved API
     endforeach()
   endif()
-endif()
+endif()

Doxyfile

@@ -99,7 +99,7 @@ OUTPUT_LANGUAGE        = English
 # Possible values are: None, LTR, RTL and Context.
 # The default value is: None.
 
-OUTPUT_TEXT_DIRECTION  = None
+#OUTPUT_TEXT_DIRECTION  = None # OBSOLETE
 
 # If the BRIEF_MEMBER_DESC tag is set to YES, doxygen will include brief member
 # descriptions after the members that are listed in the file and class
@@ -1858,7 +1858,7 @@ LATEX_HIDE_INDICES     = NO
 # The default value is: NO.
 # This tag requires that the tag GENERATE_LATEX is set to YES.
 
-LATEX_SOURCE_CODE      = NO
+# LATEX_SOURCE_CODE      = NO # OBSOLETE
 
 # The LATEX_BIB_STYLE tag can be used to specify the style to use for the
 # bibliography, e.g. plainnat, or ieeetr. See
@@ -1948,7 +1948,7 @@ RTF_EXTENSIONS_FILE    =
 # The default value is: NO.
 # This tag requires that the tag GENERATE_RTF is set to YES.
 
-RTF_SOURCE_CODE        = NO
+# RTF_SOURCE_CODE        = NO # OBSOLETE
 
 #---------------------------------------------------------------------------
 # Configuration options related to the man page output
@@ -2053,7 +2053,7 @@ DOCBOOK_OUTPUT         = docbook
 # The default value is: NO.
 # This tag requires that the tag GENERATE_DOCBOOK is set to YES.
 
-DOCBOOK_PROGRAMLISTING = NO
+#DOCBOOK_PROGRAMLISTING = NO # OBSOLETE
 
 #---------------------------------------------------------------------------
 # Configuration options for the AutoGen Definitions output

README.md

@@ -11,16 +11,26 @@ FNFT is a software library for the numerical computation of (inverse) nonlinear
 * Nonlinear Schroedinger equation
 
     * Vanishing boundary conditions
-      * Reflection coefficient and/or scattering coefficients (a and b)
-      * Bound states (eigenvalues)
-      * Norming constants and/or residues
+        * Reflection coefficient and/or scattering coefficients (a and b)
+        * Bound states (eigenvalues)
+        * Norming constants and/or residues
 
     * (Quasi-)Periodic boundary conditions
-      * Main spectrum
-      * Auxiliary spectrum
+        * Main spectrum
+        * Auxiliary spectrum
 
 * Korteweg-de Vries equation
-    * Vanishing boundary conditions (reflection coefficient only)
+
+    * Vanishing boundary conditions
+        * Reflection coefficient and/or scattering coefficients (a and b)
+        * Bound states (eigenvalues)
+        * Norming constants and/or residues
+
+* Manakov equation
+
+    * Vanishing boundary conditions
+        * Reflection coefficient and/or scattering coefficients (a, b1 and b2)
+        * Bound states (eigenvalues)
 
 ### Inverse Transforms
 
@@ -71,6 +81,7 @@ Please use the [issue tracker](https://github.com/FastNFT/FNFT/issues) to report
 * Shrinivas Chimmalgi, TU Delft
 * Peter J. Prins, TU Delft
 * Marius Brehler, TU Dortmund
+* Lianne de Vries, student TU Delft
 
 ## License
 

examples/fnft_manakovv_example.c

@@ -0,0 +1,129 @@
+/*
+ * This file is part of FNFT.
+ *
+ * FNFT is free software; you can redistribute it and/or
+ * modify it under the terms of the version 2 of the GNU General
+ * Public License as published by the Free Software Foundation.
+ *
+ * FNFT is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Contributors:
+ * Lianne de Vries (TU Delft student) 2021.
+ */
+
+#define FNFT_ENABLE_SHORT_NAMES
+
+#include <stdio.h> // for printf
+#include "fnft_manakovv.h"
+#include "fnft_manakov_discretization_t.h"
+#include "fnft__misc.h"
+
+int main()
+{
+    /** Step 1: Set up the signal **/
+
+    // Number of time-domain samples. Increase to improve precision of results.
+    FNFT_UINT D = 1024;
+
+    // Contains the samples of q(t)
+    FNFT_COMPLEX q1[D], q2[D];
+
+    // Location of the 1st and last time-domain sample
+    FNFT_REAL T[2] = { -2.0, 2.0 };
+
+    // Define a simple rectangular signal
+    // TODO: use rectangular signal
+    for (UINT i=0; i<D; i++){
+            q1[i] = 2;
+            q2[i] = 0.65;
+    }
+
+    // The types FNFT_UINT, FNFT_INT, FNFT_REAL and FNFT_COMPLEX are defined
+    // in the header fnft_numtypes.h
+
+
+    /** Step 2: Prepare calling fnft_manakovv **/ 
+
+    // Location of the 1st and last sample of the continuous spectrum
+    FNFT_REAL XI[2] = {-1.75, 2.0 };
+
+    // Number of samples of the continuous spectrum
+    FNFT_UINT M = 8;
+
+    // Buffer for result: Samples of the continuous spectrum
+    FNFT_COMPLEX contspec[3*M];
+
+
+    // Maximum number of bound states we expect = size of the two arrays below
+    FNFT_UINT K = D;        
+
+    // Buffer for result: Bound states
+    FNFT_COMPLEX bound_states[K];
+
+    // Buffer for result: Norming constants
+    FNFT_COMPLEX normconsts[K];
+
+    // Focusing nonlinear Schroedinger equation
+    int kappa = +1;
+
+    // Default options
+    fnft_manakovv_opts_t opts = fnft_manakovv_default_opts();
+    opts.discretization = manakov_discretization_2SPLIT3A;
+
+    // Uncomment the next line to compute residues instead of norming constants
+    //opts.discspec_type = fnft_nsev_dstype_RESIDUES;
+
+    // See the header file fnft_nsev.h for other options
+
+    /** Step 3: Call fnft_nsev and check for errors **/
+
+    int ret_code = fnft_manakovv(D, q1, q2, T, M, contspec, XI, &K, bound_states,
+        normconsts, kappa, &opts);
+    if (ret_code != FNFT_SUCCESS) {
+        printf("An error occured!\n");
+        return EXIT_FAILURE;
+    }
+
+    /** Step 4: Print the results **/
+
+    printf("Number of samples:\n  D = %u\n", (unsigned int)D);
+
+    FNFT_REAL eps_xi = (XI[1] - XI[0]) / (M - 1);
+    printf("Continuous spectrum (first entry):\n");
+    for (FNFT_UINT i=0; i<M; i++) {
+        FNFT_REAL xi = XI[0] + i*eps_xi;
+        printf("  continuous_spectrum(xi=%f) \t= %g + %gI\n",
+            (double)xi,
+            (double)FNFT_CREAL(contspec[i]),
+            (double)FNFT_CIMAG(contspec[i])
+        );
+    }
+
+    printf("Continuous spectrum (second entry):\n");
+    for (FNFT_UINT i=M; i<2*M; i++) {
+        FNFT_REAL xi = XI[0] + (i-8)*eps_xi;
+        printf("  continuous_spectrum(xi=%f) \t= %g + %gI\n",
+            (double)xi,
+            (double)FNFT_CREAL(contspec[i]),
+            (double)FNFT_CIMAG(contspec[i])
+        );
+    }
+
+/*    printf("Discrete spectrum:\n");
+    for (FNFT_UINT i=0; i<K; i++) {
+        printf("  bound state at %g + %gI with norming constant %g + %gI\n",
+            (double)FNFT_CREAL(bound_states[i]),
+            (double)FNFT_CIMAG(bound_states[i]),
+            (double)FNFT_CREAL(normconsts[i]),
+            (double)FNFT_CIMAG(normconsts[i])
+        );
+    }*/
+
+    return EXIT_SUCCESS;
+}

examples/mex_fnft_manakovv_example.m

@@ -0,0 +1,86 @@
+% This file is part of FNFT.  
+%                                                                  
+% FNFT is free software; you can redistribute it and/or
+% modify it under the terms of the version 2 of the GNU General
+% Public License as published by the Free Software Foundation.
+%
+% FNFT is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%                                                                      
+% You should have received a copy of the GNU General Public License
+% along with this program. If not, see <http://www.gnu.org/licenses/>.
+%
+% Contributors:
+% Sander Wahls (TU Delft) 2017-2018, 2021.
+% Lianne de Vries (TU Delft student) 2021.
+
+% This examples demonstrates how the nonlinear Fourier transform with
+% respect to the Manakov equation with vanishing boundary
+% conditions can be computed using mex_fnft_manakovv. The signal is a sech
+% pulse as discussed in 
+% http://resolver.tudelft.nl/uuid:0276e693-3408-4472-9749-b754c2114183
+
+
+clear all;
+close all;
+
+%%% Setup parameters %%%
+
+T = [-7, 7];    % location of the 1st and last sample in the time domain
+D = 512;        % number of samples
+XI = [-7/4, 8/4]; % location of the 1st and last sample in the xi-domain
+kappa = +1;     % focusing nonlinear Schroedinger equation
+
+%%% Setup the signal %%%
+
+eps_t = (T(2) - T(1)) / (D - 1);    % time domain step size
+t = T(1):eps_t:T(2);
+q1 = 0.8*sech(t);                   % signal samples
+q2 = 5.2*sech(t);
+
+%%% Compute the nonlinear Fourier transform %%%
+
+[contspec, bound_states] = mex_fnft_manakovv(complex(q1), complex(q2), ...
+    T, XI, kappa);
+% mex_fnft_manakovv has many options => run "help mex_fnft_manakovv" to
+% learn more
+
+%%% Plot the results %%%
+
+ep_xi = (XI(2) - XI(1)) / (D - 1);
+xi = XI(1):ep_xi:XI(2); % grid in the nonlinear frequency domain
+
+figure;
+plot(t, real(q1), t, imag(q1));
+title('Time-domain');
+xlabel('t');
+ylabel('q1(t)');
+legend('Real part', 'Imaginary part');
+
+figure;
+plot(t, real(q2), t, imag(q2));
+title('Time-domain');
+xlabel('t');
+ylabel('q2(t)');
+legend('Real part', 'Imaginary part');
+
+% Note: plotting the results for the default case where 
+% contspec = [rho1; rho2]. If different inputs are chosen for cstype or M
+% plots should be adjusted
+figure;
+plot(xi, real(contspec(1:length(contspec)/2)), xi, ...
+    imag(contspec(1:length(contspec)/2)));
+title('Continuous spectrum, first element');
+xlabel('\xi');
+ylabel('r(\xi)');
+legend('Real part', 'Imaginary part');
+
+figure;
+plot(xi, real(contspec(length(contspec)/2+1:length(contspec))), xi, ...
+    imag(contspec(length(contspec)/2+1:length(contspec))));
+title('Continuous spectrum, second element');
+xlabel('\xi');
+ylabel('r(\xi)');
+legend('Real part', 'Imaginary part');