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In this article one can find the following expression on Appendix B (typos also transcribed):

$$ z_k = \mathcal{Re}\sum_{j = 1}^{N}\text{Complx}(D_{jj}y_j, D_{j + N\;j+n}y_{j + n})^*\times\text{Complx}(A_{jk}, A_{j+N\;k}), $$ where $^*$ stands for complex conjugation.

What does $\text{Complx}(D_{jj}y_j, D_{j + N\;j+n}y_{j + n})$ stand for?

Does it stand for the complex number $z_k$ defined by $D_{jj}y_j$ as its real part and $D_{j + N\;j+n}y_{j + n}$ as its imaginary part?

Googling "Complx" did not really help, and I have never encountered such notation before... It seems like a constructor for complex numbers :)

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Yes, the paragraph right before the first occurrence of the expression implies that $\mathrm{Complx}(a,b)=a+bi$.

... the vector $\mathbf{y}$ is real with dimension $2N$, where $N$ is the number of complex data points used in the inversion. ... For compact programmable expressions, we let the vector $\mathbf{y}$ ... be redefined as complex so that they can be conveniently stored in the computer memory. ... we have for the $j$th element of the first matrix-vector multiplication $$y_j=\mathrm{Complx}\Bigl\{\cdots\Bigr\}$$

(original text)

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    I don't really see how to redefine this as complex makes it "programmable"... I am still reading the entire thing :) – 2017-02-21
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    As a more interesting comment, a question: Why would they just get the real part out of the equation? Shouldn't the expression yield a real value without being forced to be real? It stills baffles me why they just take the real part by simply saying: "$z_k$ must be real". Although, when analysis harmonic signals, the real part foes have its meaning... – 2017-02-21