solve_nakamura-ueta_eqs.c

/*----------------------------------------------------------------------------------

中村・上田写像とヤコビ行列（線形化した中村・上田写像）

Nakamura-Ueta map and the Jacobian matrix (linearized Nakamura-Ueta map)

solve_nakamura-ueta_eqs.c

----------------------------------------------------------------------------------*/

#include "nakamura-ueta_lyap.h"

void nakamura_ueta_eqs( double (*x), double (*y), double (*z), double dfQ[DIM][DIM], double Q[DIM][DIM] )

{

int i, j, k;

double xx;

double yy;

double zz;

double d2;

double df[DIM][DIM]; // ヤコビ行列

// 中村・上田写像

// Nakamura-Ueta map

xx = A0 + A1 * (*y) + A2 * (*x) * (*z);

yy = (*x);

zz = (*y);

(*x) = xx;

(*y) = yy;

(*z) = zz;

// ヤコビ行列/

// Jacobian  matrix

df[0][0] = A2 * (*z);

df[0][1] = A1;

df[0][2] = A2 * (*x);

df[1][0] = 1.0;

df[1][1] = 0.0;

df[1][2] = 0.0;

df[2][0] = 0.0;

df[2][1] = 1.0;

df[2][2] = 0.0;

/*

｜ df[0][0]  df[0][1]  df[0][2] ｜

｜ ｜

df = ｜ df[1][0]  df[1][1]  df[1][2] ｜

｜ ｜

｜ df[2][0]  df[2][1]  df[2][2] ｜

*/

// ヤコビ行列dfと行列Qの積dfQの計算

// calculate the product dfQ of the Jacobian matrix df and the matrix Q

for ( i = 0; i < DIM; i++ ) {

for ( j = 0; j < DIM; j++ ) {

d2 = 0.0;

for ( k = 0; k < DIM; k++ ) {

d2 += df[i][k] * Q[k][j];

}

dfQ[i][j] = d2;

}

}

}