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00001 // Copyright (C) 2003 Johan Jansson. 00002 // Licensed under the GNU GPL Version 2. 00003 // 00004 // Modified by Anders Logg 2003, 2004. 00005 00006 #include <dolfin.h> 00007 00008 using namespace dolfin; 00009 00010 class TestProblem8 : public ODE 00011 { 00012 public: 00013 00014 TestProblem8() : ODE(3) 00015 { 00016 dolfin_info("System of fast and slow chemical reactions, taken from the book by"); 00017 dolfin_info("Hairer and Wanner, page 3."); 00018 00019 // Final time 00020 T = 0.3; 00021 00022 // Compute sparsity 00023 sparse(); 00024 } 00025 00026 real u0(unsigned int i) 00027 { 00028 if ( i == 0 ) 00029 return 1.0; 00030 else 00031 return 0.0; 00032 } 00033 00034 real f(const Vector& u, real t, unsigned int i) 00035 { 00036 //if ( i == 1 ) 00037 // dolfin_info("t = %.16e u = [%.16e %.16e %.16e]", t, u(0), u(1), u(2)); 00038 00039 if ( i == 0 ) 00040 return -0.04 * u(0) + 1.0e4 * u(1) * u(2); 00041 00042 if ( i == 1 ) 00043 return 0.04 * u(0) - 1.0e4 * u(1) * u(2) - 3.0e7 * u(1) * u(1); 00044 00045 return 3.0e7 * u(1) * u(1); 00046 } 00047 00048 };
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