real

Builtin index · Core maths

result = re(x)

Input: x · Output: result

What it is

Real component of a Complex/CVec/CMat (identity — x passed through unchanged — when x is already real). x is a scalar, Vec, or Mat (real or complex).

Overloads

One call shape — this function is not overloaded.

Code	Input	Output	Description
`result = re(x)`	`x` Complex, CVec, Vec, CMat, Mat, or scalarnot documented yet	`result` Complex, Num, CVec, Vec, CMat, or Mat	Returns the same shape as `x` but always real-valued — a `Complex` gives a `Num`, a `CVec` a real `Vec`, a `CMat` a real `Mat`.

Examples

From the documentation, and run by the build -- the output and the figure below are what the engine actually produced. Simplest first.

xr = real(ifft(X, N))
print("round-trip err = {max(abs(xr - x)):.2e}")

output

round-trip err = 4.93e-32

from numerics-dsp

t = 1, 2, ..., 50        # N = 50, not a power of two

x = sin(t)
X = fft(x)
print("length(X) = {length(X)}")
print("round trip err = {max(abs(real(ifft(X)) - x)):.2e}")