<valarray> functions
The latest version of this topic can be found at <valarray> functions.
| abs | acos | asin |
| atan | atan2 | cos |
| cosh | exp | log |
| log10 | pow | sin |
| sinh | sqrt | swap |
| tan | tanh |
abs
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the absolute value of the elements of the input valarray.
template <class Type>
valarray<Type> abs(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the absolute value of the elements of the input valarray.
Example
// valarray_abs.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
int main( )
{
using namespace std;
int i;
valarray<int> va1 ( 9 ), va2 ( 9 );
for ( i = 0 ; i < 4 ; i++ )
va1 [ i ] = -i;
for ( i = 4 ; i < 9 ; i++ )
va1 [ i ] = i;
cout << "The initial valarray is: ";
for (i = 0 ; i < 9 ; i++ )
cout << va1 [ i ] << " ";
cout << "." << endl;
va2 = abs ( va1 );
cout << "The absolute value of the initial valarray is: ";
for (i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << " ";
cout << "." << endl;
}
The initial valarray is: 0 -1 -2 -3 4 5 6 7 8 .
The absolute value of the initial valarray is: 0 1 2 3 4 5 6 7 8 .
acos
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the arccosine of the elements of the input valarray.
template <class Type>
valarray<Type> acos(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the arccosine of the elements of the input valarray.
Remarks
The units of the returned elements are in radians.
The return value is a principal value between 0 and +pi that is consistent with the cosine value input.
Example
// valarray_acos.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = 0.25 * i - 1;
valarray<double> va2 ( 9 );
cout << "The initial valarray is:";
for (i = 0 ; i < 9 ; i++ )
cout << " " << va1 [ i ];
cout << endl;
va2 = acos ( va1 );
cout << "The arccosine of the initial valarray is:\n";
for (i = 0 ; i < 9 ; i++ )
cout << setw(10) << va2 [ i ]
<< " radians, which is "
<< setw(11) << (180/pi) * va2 [ i ]
<< " degrees" << endl;
}
The initial valarray is: -1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1
The arccosine of the initial valarray is:
3.14159 radians, which is 180 degrees
2.41886 radians, which is 138.59 degrees
2.0944 radians, which is 120 degrees
1.82348 radians, which is 104.478 degrees
1.5708 radians, which is 90 degrees
1.31812 radians, which is 75.5225 degrees
1.0472 radians, which is 60 degrees
0.722734 radians, which is 41.4096 degrees
0 radians, which is 0 degrees
asin
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the arcsine of the elements of the input valarray.
template <class Type>
valarray<Type> asin(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the arcsine of the elements of the input valarray.
Remarks
The units of the returned elements are in radians.
The return value is a principal value between +pi/2 and –pi/2 that is consistent with the sine value input.
Example
// valarray_asin.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = 0.25 * i - 1;
valarray<double> va2 ( 9 );
cout << "The initial valarray is:";
for (i = 0 ; i < 9 ; i++ )
cout << " " << va1 [ i ];
cout << endl;
va2 = asin ( va1 );
cout << "The arcsine of the initial valarray is:\n";
for (i = 0 ; i < 9 ; i++ )
cout << setw(10) << va2 [ i ]
<< " radians, which is "
<< setw(11) << (180/pi) * va2 [ i ]
<< " degrees" << endl;
}
The initial valarray is: -1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1
The arcsine of the initial valarray is:
-1.5708 radians, which is -90 degrees
-0.848062 radians, which is -48.5904 degrees
-0.523599 radians, which is -30 degrees
-0.25268 radians, which is -14.4775 degrees
0 radians, which is 0 degrees
0.25268 radians, which is 14.4775 degrees
0.523599 radians, which is 30 degrees
0.848062 radians, which is 48.5904 degrees
1.5708 radians, which is 90 degrees
atan
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the principal value of the arctangent of the elements of the input valarray.
template <class Type>
valarray<Type> atan(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the arctangent of the elements of the input valarray.
Remarks
The units of the returned elements are in radians.
The return value is a principal value between +pi/2 and –pi/2 that is consistent with the tangent value input.
Example
// valarray_atan.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
va1 [ 0 ] = -100;
for ( i = 1 ; i < 8 ; i++ )
va1 [ i ] = 5 * ( 0.25 * i - 1 );
va1 [ 8 ] = 100;
valarray<double> va2 ( 9 );
cout << "The initial valarray is: ";
for ( i = 0 ; i < 9 ; i++ )
cout << va1 [ i ] << " ";
cout << "." << endl;
va2 = atan ( va1 );
cout << "The arcsine of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << setw(10) << va2 [ i ]
<< " radians, which is "
<< setw(11) << (180/pi) * va2 [ i ]
<< " degrees" << endl;
cout << endl;
}
The initial valarray is: -100 -3.75 -2.5 -1.25 0 1.25 2.5 3.75 100 .
The arcsine of the initial valarray is:
-1.5608 radians, which is -89.4271 degrees
-1.31019 radians, which is -75.0686 degrees
-1.19029 radians, which is -68.1986 degrees
-0.896055 radians, which is -51.3402 degrees
0 radians, which is 0 degrees
0.896055 radians, which is 51.3402 degrees
1.19029 radians, which is 68.1986 degrees
1.31019 radians, which is 75.0686 degrees
1.5608 radians, which is 89.4271 degrees
atan2
Returns a valarray whose elements are equal to the arctangent of the Cartesian components specified by a combination of constants and elements of valarrays.
template <class Type>
valarray<Type> atan2(const valarray<Type>& left, const valarray<Type>& right);
template <class Type>
valarray<Type> atan2(const valarray<Type> left, const Type& right);
template <class Type>
valarray<Type> atan2(const Type& left, const valarray<Type>& right);
Parameters
left
The constant numerical data type or input valarray whose elements provide the values for the y-coordinate of the arctangent argument.
right
The constant numerical data type or input valarray whose elements provide the values for the x-coordinate of the arctangent argument.
Return Value
A valarray whose elements I are equal to the arctangent of:
left[ I ] / _Right [ I ] for the first template function.left[ I ] /rightfor the second template function.left/right[ I ] for the third template function.
Remarks
The units of the returned elements are in radians.
This function preserves information about the signs of the components in the argument that is lost by the standard tangent function, and this knowledge of the quadrant enables the return value to be assigned a unique angle between +pi and –pi.
If left and right have a different number of elements, the result is undefined.
Example
// valarray_atan2.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1y ( 1 , 4 ), va1x ( 1 , 4 );
va1x [ 1 ] = -1;
va1x [ 2 ] = -1;
va1y [ 2 ] = -1;
va1y [ 3 ] = -1;
valarray<double> va2 ( 4 );
cout << "The initial valarray for the x coordinate is: ( ";
for ( i = 0 ; i < 4 ; i++ )
cout << va1x [ i ] << " ";
cout << ")." << endl;
cout << "The initial valarray for the y coordinate is: ( ";
for ( i = 0 ; i < 4 ; i++ )
cout << va1y [ i ] << " ";
cout << ")." << endl;
va2 = atan2 ( va1y , va1x );
cout << "The atan2 ( y / x ) of the initial valarrays is:\n";
for ( i = 0 ; i < 4 ; i++ )
cout << setw( 10 ) << va2 [ i ]
<< " radians, which is "
<< setw( 11 ) << ( 180/pi ) * va2 [ i ]
<< "degrees" << endl;
cout << endl;
}
The initial valarray for the x coordinate is: ( 1 -1 -1 1 ).
The initial valarray for the y coordinate is: ( 1 1 -1 -1 ).
The atan2 ( y / x ) of the initial valarrays is:
0.785398 radians, which is 45degrees
2.35619 radians, which is 135degrees
-2.35619 radians, which is -135degrees
-0.785398 radians, which is -45degrees
cos
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the cosine of the elements of the input valarray.
template <class Type>
valarray<Type> cos(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the absolute value of the elements of the input valarray.
Example
// valarray_cos.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = ( pi ) * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );
cout << "The initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << setw( 10 ) << va1 [ i ]
<< " radians, which is "
<< setw( 5 ) << ( 180/pi ) * va1 [ i ]
<< " degrees" << endl;
cout << endl;
va2 = cos ( va1 );
cout << "The cosine of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
The initial valarray is:
-3.14159 radians, which is -180 degrees
-2.35619 radians, which is -135 degrees
-1.5708 radians, which is -90 degrees
-0.785398 radians, which is -45 degrees
0 radians, which is 0 degrees
0.785398 radians, which is 45 degrees
1.5708 radians, which is 90 degrees
2.35619 radians, which is 135 degrees
3.14159 radians, which is 180 degrees
The cosine of the initial valarray is:
-1
-0.707107
-1.03412e-013
0.707107
1
0.707107
-1.03412e-013
-0.707107
-1
cosh
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the hyperbolic cosine of the elements of the input valarray.
template <class Type>
valarray<Type> cosh(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the hyperbolic cosine of the elements of the input valarray.
Remarks
Identities defining the hyperbolic cosine in terms of exponential function:
cosh ( z ) = ( exp ( z ) + exp ( - z ) ) / 2
Example
// valarray_cosh.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = pi * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );
cout << "The initial valarray is:\n";
for (i = 0 ; i < 9 ; i++ )
cout << setw( 10 ) << va1 [ i ]
<< " radians, which is "
<< setw( 5 ) << ( 180/pi ) * va1 [ i ]
<< " degrees" << endl;
cout << endl;
va2 = cosh ( va1 );
cout << "The hyperbolic cosine of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
The initial valarray is:
-3.14159 radians, which is -180 degrees
-2.35619 radians, which is -135 degrees
-1.5708 radians, which is -90 degrees
-0.785398 radians, which is -45 degrees
0 radians, which is 0 degrees
0.785398 radians, which is 45 degrees
1.5708 radians, which is 90 degrees
2.35619 radians, which is 135 degrees
3.14159 radians, which is 180 degrees
The hyperbolic cosine of the initial valarray is:
11.592
5.32275
2.50918
1.32461
1
1.32461
2.50918
5.32275
11.592
exp
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the natural exponential of the elements of the input valarray.
template <class Type>
valarray<Type> exp(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the natural exponential of the elements of the input valarray.
Example
// valarray_exp.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = 10 * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );
cout << "Initial valarray:";
for ( i = 0 ; i < 9 ; i++ )
cout << " " << va1 [ i ];
cout << endl;
va2 = exp ( va1 );
cout << "The natural exponential of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
Initial valarray: -10 -7.5 -5 -2.5 0 2.5 5 7.5 10
The natural exponential of the initial valarray is:
4.53999e-005
0.000553084
0.00673795
0.082085
1
12.1825
148.413
1808.04
22026.5
log
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the natural logarithm of the elements of the input valarray.
template <class Type>
valarray<Type> log(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the absolute value of the elements of the input valarray.
Example
// valarray_log.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
int i;
valarray<double> va1 ( 9 );
for (i = 0 ; i < 9 ; i++ )
va1 [ i ] = 10 * i;
valarray<double> va2 ( 9 );
cout << "Initial valarray:";
for ( i = 0 ; i < 9 ; i++ )
cout << " " << va1 [ i ];
cout << endl;
va2 = log ( va1 );
cout << "The natural logarithm of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
Initial valarray: 0 10 20 30 40 50 60 70 80
The natural logarithm of the initial valarray is:
-1.#INF
2.30259
2.99573
3.4012
3.68888
3.91202
4.09434
4.2485
4.38203
log10
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the base 10 or common logarithm of the elements of the input valarray.
template <class Type>
valarray<Type> log10(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the common logarithm of the elements of the input valarray.
Example
// valarray_log10.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
int i;
valarray<double> va1 ( 11 );
for ( i = 0 ; i < 11 ; i++ )
va1 [ i ] = 10 * i;
valarray<double> va2 ( 9 );
cout << "Initial valarray:";
for (i = 0 ; i < 11 ; i++ )
cout << " " << va1 [ i ];
cout << endl;
va2 = log10 ( va1 );
cout << "The common logarithm of the initial valarray is:\n";
for (i = 0 ; i < 11 ; i++ )
cout << va2 [ i ] << endl;
}
Initial valarray: 0 10 20 30 40 50 60 70 80 90 100
The common logarithm of the initial valarray is:
-1.#INF
1
1.30103
1.47712
1.60206
1.69897
1.77815
1.8451
1.90309
1.95424
2
pow
Operates on the elements of input valarrays and constants, returning a valarray whose elements are equal to a base specified either by the elements of an input valarray or a constant raised to an exponent specified either by the elements of an input valarray or a constant.
template <class Type>
valarray<Type>
pow(
const valarray<Type>& left,
const valarray<Type>& right);
template <class Type>
valarray<Type>
pow(
const valarray<Type>& left,
const Type& right);
template <class Type>
valarray<Type>
pow(
const Type& left,
const valarray<Type>& right);
Parameters
left
The input valarray whose elements supply the base for each element to be exponentiated.
right
The input valarray whose elements supply the power for each element to be exponentiated.
Return Value
A valarray whose elements I are equal to:
left[ I ] raised to the powerright[ I ] for the first template function.left[ I ] raised to the powerrightfor the second template function.leftraised to the powerright[ I ] for the third template function.
Remarks
If left and right have a different number of elements, the result is undefined.
Example
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> vabase ( 6 );
for ( i = 0 ; i < 6 ; i++ )
vabase [ i ] = i/2;
valarray<double> vaexp ( 6 );
for ( i = 0 ; i < 6 ; i++ )
vaexp [ i ] = 2 * i;
valarray<double> va2 ( 6 );
cout << "The initial valarray for the base is: ( ";
for ( i = 0 ; i < 6 ; i++ )
cout << vabase [ i ] << " ";
cout << ")." << endl;
cout << "The initial valarray for the exponent is: ( ";
for ( i = 0 ; i < 6 ; i++ )
cout << vaexp[ i ] << " ";
cout << ")." << endl;
va2 = pow ( vabase , vaexp );
cout << "The power of (n/2) * exp (2n) for n = 0 to n = 5 is: \n";
for ( i = 0 ; i < 6 ; i++ )
cout << "n = " << i << "\tgives " << va2 [ i ] << endl;
}
The initial valarray for the base is: ( 0 0 1 1 2 2 ).
The initial valarray for the exponent is: ( 0 2 4 6 8 10 ).
The power of (n/2) * exp (2n) for n = 0 to n = 5 is:
n = 0 gives 1
n = 1 gives 0
n = 2 gives 1
n = 3 gives 1
n = 4 gives 256
n = 5 gives 1024
sin
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the sine of the elements of the input valarray.
template <class Type>
valarray<Type> sin(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the sine of the elements of the input valarray.
Example
// valarray_sin.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = pi * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );
cout << "The initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << setw(10) << va1 [ i ]
<< " radians, which is "
<< setw(5) << ( 180/pi ) * va1 [ i ]
<< " degrees" << endl;
cout << endl;
va2 = sin ( va1 );
cout << "The sine of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
The initial valarray is:
-3.14159 radians, which is -180 degrees
-2.35619 radians, which is -135 degrees
-1.5708 radians, which is -90 degrees
-0.785398 radians, which is -45 degrees
0 radians, which is 0 degrees
0.785398 radians, which is 45 degrees
1.5708 radians, which is 90 degrees
2.35619 radians, which is 135 degrees
3.14159 radians, which is 180 degrees
The sine of the initial valarray is:
2.06823e-013
-0.707107
-1
-0.707107
0
0.707107
1
0.707107
-2.06823e-013
sinh
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the hyperbolic sine of the elements of the input valarray.
template <class Type>
valarray<Type> sinh(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the hyperbolic sine of the elements of the input valarray.
Remarks
Identities defining the hyperbolic sine in terms of exponential function:
sinh ( z ) = ( exp ( z ) – exp ( - z ) ) / 2
Example
// valarray_sinh.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for (i = 0 ; i < 9 ; i++ )
va1 [ i ] = pi * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );
cout << "The initial valarray is:\n";
for (i = 0 ; i < 9 ; i++ )
cout << setw( 10 ) << va1 [ i ]
<< " radians, which is "
<< setw( 5 ) << ( 180/pi ) * va1 [ i ]
<< " degrees" << endl;
cout << endl;
va2 = sinh ( va1 );
cout << "The hyperbolic sine of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
The initial valarray is:
-3.14159 radians, which is -180 degrees
-2.35619 radians, which is -135 degrees
-1.5708 radians, which is -90 degrees
-0.785398 radians, which is -45 degrees
0 radians, which is 0 degrees
0.785398 radians, which is 45 degrees
1.5708 radians, which is 90 degrees
2.35619 radians, which is 135 degrees
3.14159 radians, which is 180 degrees
The hyperbolic sine of the initial valarray is:
-11.5487
-5.22797
-2.3013
-0.868671
0
0.868671
2.3013
5.22797
11.5487
sqrt
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the square root of the elements of the input valarray.
template <class Type>
valarray<Type> sqrt(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the square root of the elements of the input valarray.
Example
// valarray_sqrt.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <cmath>
int main( )
{
using namespace std;
int i;
valarray<double> va1 ( 6 );
for ( i = 0 ; i < 5 ; i++ )
va1 [ i ] = i * i;
cout << "The initial valarray is: ( ";
for ( i = 0 ; i < 5 ; i++ )
cout << va1 [ i ] << " ";
cout << ")." << endl;
valarray<double> va2 = sqrt ( va1 );
cout << "The square root of the initial valarray is: ( ";
for ( i = 0 ; i < 5 ; i++ )
cout << va2 [ i ] << " ";
cout << ")." << endl;
}
The initial valarray is: ( 0 1 4 9 16 ).
The square root of the initial valarray is: ( 0 1 2 3 4 ).
swap
Exchanges the elements of two valarrays.
template <class Type>
void swap(
valarray<Type>& left,
valarray<Type>& right);
Parameters
| Parameter | Description |
|---|---|
left |
An object of type valarray. |
right |
An object of type valarray. |
Remarks
The template function executes left.swap( right).
tan
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the tangent of the elements of the input valarray.
template <class Type>
valarray<Type> tan(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the tangent of the elements of the input valarray.
Example
// valarray_tan.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = ( pi/2 ) * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );
cout << "The initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << setw( 10 ) << va1 [ i ]
<< " radians, which is "
<< setw( 5 ) << ( 180/pi ) * va1 [ i ]
<< " degrees" << endl;
cout << endl;
va2 = tan ( va1 );
cout << "The tangent of the initial valarray is:\n ";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
The initial valarray is:
-1.5708 radians, which is -90 degrees
-1.1781 radians, which is -67.5 degrees
-0.785398 radians, which is -45 degrees
-0.392699 radians, which is -22.5 degrees
0 radians, which is 0 degrees
0.392699 radians, which is 22.5 degrees
0.785398 radians, which is 45 degrees
1.1781 radians, which is 67.5 degrees
1.5708 radians, which is 90 degrees
The tangent of the initial valarray is:
9.6701e+012
-2.41421
-1
-0.414214
0
0.414214
1
2.41421
-9.6701e+012
tanh
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the hyperbolic tangent of the elements of the input valarray.
template <class Type>
valarray<Type> tanh(const valarray<Type>& left);
Parameters
left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the hyperbolic cosine of the elements of the input valarray.
Remarks
Identities defining the hyperbolic tangent in terms of the exponential function:
tanh ( z ) = sinh ( z ) / cosh ( z ) = ( exp ( z ) – exp ( - z ) ) / ( exp ( z ) + exp ( - z ) )
Example
// valarray_tanh.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = pi * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );
cout << "The initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << setw( 10 ) << va1 [ i ]
<< " radians, which is "
<< setw( 5 ) << ( 180/pi ) * va1 [ i ]
<< " degrees" << endl;
cout << endl;
va2 = tanh ( va1 );
cout << "The hyperbolic tangent of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
The initial valarray is:
-3.14159 radians, which is -180 degrees
-2.35619 radians, which is -135 degrees
-1.5708 radians, which is -90 degrees
-0.785398 radians, which is -45 degrees
0 radians, which is 0 degrees
0.785398 radians, which is 45 degrees
1.5708 radians, which is 90 degrees
2.35619 radians, which is 135 degrees
3.14159 radians, which is 180 degrees
The hyperbolic tangent of the initial valarray is:
-0.996272
-0.982193
-0.917152
-0.655794
0
0.655794
0.917152
0.982193
0.996272