Documentation

cordictanh

CORDIC-based hyperbolic tangent

Syntax

T = cordictanh(theta)
T = cordictanh(theta, niters)

Description

example

T = cordictanh(theta) returns the hyperbolic tangent of theta.

example

T = cordictanh(theta, niters) returns the hyperbolic tangent of theta by performing niters iterations of the CORDIC algorithm.

Examples

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Find the hyperbolic tangent of fi object theta using a CORDIC implementation with the default number of iterations.

theta = fi(-2*pi:.1:2*pi-.1);
T_cordic = cordictanh(theta);

Plot the hyperbolic tangent of theta using the tanh function and its CORDIC approximation.

T = tanh(double(theta));
plot(theta, T_cordic);
hold on;
plot(theta, T);
legend('CORDIC approximation of tanh', 'tanh');
xlabel('theta');
ylabel('tanh(theta)');

Compute the difference between the results of the cordictanh function and the tanh function.

figure;
err = abs(T - double(T_cordic));
plot(theta, err);
xlabel('theta');
ylabel('error');

Find the hyperbolic tangent of fi object theta using a CORDIC implementation and specify the number of iterations the CORDIC kernel should perform. Plot the CORDIC approximation of the hyperbolic tangent of theta with varying numbers of iterations.

theta = fi(-2*pi:.1:2*pi-.1);
for niters = 5:10:25
T_cordic = cordictanh(theta, niters);
plot(theta, T_cordic);
hold on;
end
xlabel('theta');
ylabel('tanh(theta)');
legend('5 iterations', '15 iterations', '25 iterations','Location','southeast');

Input Arguments

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Angle values in radians specified as a scalar, vector, matrix, or N-dimensional array.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fi

The number of iterations that the CORDIC algorithm performs, specified as a positive, integer-valued scalar. If you do not specify niters, the algorithm uses a default value. For fixed-point inputs, the default value of niters is one less than the word length of the input array, theta. For double-precision inputs, the default value of niters is 52. For single-precision inputs, the default value is 23.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fi

Output Arguments

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T is the CORDIC-based approximation of the hyperbolic tangent of theta. When the input to the function is floating point, the output data type is the same as the input data type. When the input is fixed point, the output has the same word length as the input, and a fraction length equal to the WordLength2.

Introduced in R2017b

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