valarray
をテンプレートにして作成
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開始行:
std::valarray
-----
#contents
-----
*valarray [#o2cfbaf8]
数値計算用の配列．element-wiseな計算ができる．
たとえば，値が入った二つの配列 a[10], b[10] を要素ごとに...
valarrayを使わない場合は，
for(int i = 0; i < 10; ++i) c[i] = a[i]+b[i];
となるが，valarrayを使った場合，
c = a+b
でよい．absやexp,sin,cosといったcmathで定義されている数学...
そのほか，sumやmin,max,shiftなどのメンバ関数もある．
*例 [#x2699720]
#code(C){{
//! valarray型に<<オペレータを設定
template<typename T>
inline std::ostream &operator<<(std::ostream &out, const ...
{
for(size_t i = 0; i < x.size(); ++i){
out << x[i] << (i == x.size()-1 ? "" : ", ");
}
return out;
}
int main(void)
{
double val[] = {1.0, 2.0, 3.0, 4.0};
valarray<double> x(val, 4);
valarray<double> y(3.0, 4);
cout << "x = " << x << endl;
cout << "y = " << y << endl;
cout << "2*y+x = " << 2.0*y+x << endl;
cout << "exp(x) = " << exp(x) << endl;
cout << "sin(x) = " << sin(x) << endl;
cout << "max(x) = " << x.max() << endl;
cout << "min(x) = " << x.min() << endl;
cout << "sum(x) = " << x.sum() << endl;
cout << "cshift(x, 2) = " << x.cshift(2) << endl;
cout << "cshift(x, -1) = " << x.cshift(-1) << endl;
cout << "shift(x, 2) = " << x.shift(2) << endl;
cout << "shift(x, -1) = " << x.shift(-1) << endl;
cout << "pow(x, 2) = " << pow(x, 2.0) << endl;
cout << "pow(2, x) = " << pow(2.0, x) << endl;
return 0;
}
}}
実行結果は，
x = 1, 2, 3, 4
y = 3, 3, 3, 3
2*y+x = 7, 8, 9, 10
exp(x) = 2.71828, 7.38906, 20.0855, 54.5982
sin(x) = 0.841471, 0.909297, 0.14112, -0.756802
max(x) = 4
min(x) = 1
sum(x) = 10
cshift(x, 2) = 3, 4, 1, 2
cshift(x, -1) = 4, 1, 2, 3
shift(x, 2) = 3, 4, 0, 0
shift(x, -1) = 0, 1, 2, 3
pow(x, 2) = 1, 4, 9, 16
pow(2, x) = 2, 4, 8, 16
*参考 [#uca20c7e]
-http://en.cppreference.com/w/cpp/numeric/valarray
-http://www.cplusplus.com/reference/std/valarray/valarray/
終了行:
std::valarray
-----
#contents
-----
*valarray [#o2cfbaf8]
数値計算用の配列．element-wiseな計算ができる．
たとえば，値が入った二つの配列 a[10], b[10] を要素ごとに...
valarrayを使わない場合は，
for(int i = 0; i < 10; ++i) c[i] = a[i]+b[i];
となるが，valarrayを使った場合，
c = a+b
でよい．absやexp,sin,cosといったcmathで定義されている数学...
そのほか，sumやmin,max,shiftなどのメンバ関数もある．
*例 [#x2699720]
#code(C){{
//! valarray型に<<オペレータを設定
template<typename T>
inline std::ostream &operator<<(std::ostream &out, const ...
{
for(size_t i = 0; i < x.size(); ++i){
out << x[i] << (i == x.size()-1 ? "" : ", ");
}
return out;
}
int main(void)
{
double val[] = {1.0, 2.0, 3.0, 4.0};
valarray<double> x(val, 4);
valarray<double> y(3.0, 4);
cout << "x = " << x << endl;
cout << "y = " << y << endl;
cout << "2*y+x = " << 2.0*y+x << endl;
cout << "exp(x) = " << exp(x) << endl;
cout << "sin(x) = " << sin(x) << endl;
cout << "max(x) = " << x.max() << endl;
cout << "min(x) = " << x.min() << endl;
cout << "sum(x) = " << x.sum() << endl;
cout << "cshift(x, 2) = " << x.cshift(2) << endl;
cout << "cshift(x, -1) = " << x.cshift(-1) << endl;
cout << "shift(x, 2) = " << x.shift(2) << endl;
cout << "shift(x, -1) = " << x.shift(-1) << endl;
cout << "pow(x, 2) = " << pow(x, 2.0) << endl;
cout << "pow(2, x) = " << pow(2.0, x) << endl;
return 0;
}
}}
実行結果は，
x = 1, 2, 3, 4
y = 3, 3, 3, 3
2*y+x = 7, 8, 9, 10
exp(x) = 2.71828, 7.38906, 20.0855, 54.5982
sin(x) = 0.841471, 0.909297, 0.14112, -0.756802
max(x) = 4
min(x) = 1
sum(x) = 10
cshift(x, 2) = 3, 4, 1, 2
cshift(x, -1) = 4, 1, 2, 3
shift(x, 2) = 3, 4, 0, 0
shift(x, -1) = 0, 1, 2, 3
pow(x, 2) = 1, 4, 9, 16
pow(2, x) = 2, 4, 8, 16
*参考 [#uca20c7e]
-http://en.cppreference.com/w/cpp/numeric/valarray
-http://www.cplusplus.com/reference/std/valarray/valarray/
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