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46 lines
1.4 KiB
C
46 lines
1.4 KiB
C
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#ifndef GRID_MATH_DET_H
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#define GRID_MATH_DET_H
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namespace Grid {
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///////////////////////////////////////////////
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// Determinant function for scalar, vector, matrix
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///////////////////////////////////////////////
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inline ComplexF Determinant( const ComplexF &arg){ return arg;}
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inline ComplexD Determinant( const ComplexD &arg){ return arg;}
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inline RealF Determinant( const RealF &arg){ return arg;}
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inline RealD Determinant( const RealD &arg){ return arg;}
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template<class vtype> inline auto Determinant(const iScalar<vtype>&r) -> iScalar<decltype(Determinant(r._internal))>
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{
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iScalar<decltype(Determinant(r._internal))> ret;
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ret._internal = Determinant(r._internal);
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return ret;
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}
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template<class vtype,int N, typename std::enable_if< GridTypeMapper<vtype>::TensorLevel == 0 >::type * =nullptr>
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inline iScalar<vtype> Determinant(const iMatrix<vtype,N> &arg)
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{
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iMatrix<vtype,N> ret(arg);
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iScalar<vtype> det = vtype(1.0);
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/* Conversion of matrix to upper triangular */
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for(int i = 0; i < N; i++){
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for(int j = 0; j < N; j++){
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if(j>i){
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vtype ratio = ret._internal[j][i]/ret._internal[i][i];
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for(int k = 0; k < N; k++){
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ret._internal[j][k] -= ratio * ret._internal[i][k];
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}
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}
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}
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}
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for(int i = 0; i < N; i++)
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det *= ret._internal[i][i];
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return det;
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}
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}
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#endif
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