Biblatex: Inconsistent citation format

Question

I am using same format of .bib file entry, but get different output formats in beamer. Here is the MWE:

\documentclass{beamer}

\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}

%% Bibliography
\usepackage[backend=biber,style=alphabetic,citestyle=authoryear]{biblatex}
\bibliography{bibfile.bib}

\begin{document}

\begin{frame}{Trial frame}
\cite{Borzacchiello2017} \\
\cite{LEGUENNEC2018} \\
\cite{Goldfarb2014} \\
\end{frame}

\begin{frame}[allowframebreaks]{References}
    \printbibliography
\end{frame}

\end{document}

with the following .bib file entries:

@article{LEGUENNEC2018,
    author = "Le Guennec, Yves 
         and Brunet, Jean-Patrick 
         and Daim, Fatima Zohra 
         and Chau, Ming 
         and Tourbier, Yves",
    title = "A parametric and non-intrusive reduced order model of car crash simulation",
    journal = "Computer Methods in Applied Mechanics and Engineering",
    year = "2018",
}

@Article{Borzacchiello2017,
    author="Borzacchiello, Domenico
        and Aguado, Jos{\'e} V.
        and Chinesta, Francisco",
    title="Non-intrusive Sparse Subspace Learning for Parametrized Problems",
    journal="Archives of Computational Methods in Engineering",
    year = "2017",
}

@article{Goldfarb2014,
    author = "Goldfarb, Donald and Qin, Zhiwei",
    title = "Robust Low-Rank Tensor Recovery: Models and Algorithms",
    journal = "SIAM Journal on Matrix Analysis and Applications",
    year = "2014",
}

But I get the following output. As you can see the format is different in reference slide and citation as well:

I would like to have:

1) citation format : "FirstAuthor Year", preferably without "et. al"

2) Reference slide format: names of all authors, with first names abbreviated

Answer 1

To control the namelists according to your specifications, biblatex's package options are enough. maxcitenames=1 will give citations with only the first author (regularly, with "et al."); maxbibnames=99 should be enough for normal cases to include all authors in the bibliography; giveninits=true will abbreviate given names throughout.

To remove the "et al." of shortened authors lists a simple solution is to redefine the corresponding localization string with:

\DefineBibliographyStrings{english}{andothers={}}

Indeed, since version 3.13, biblatex offers support to this procedure. In particular, you should use nohashothers=true when removing the "et al." string to allow biblatex to generate unique labels for your citations. You can also fine-tune sorting in this case with the option nosortothers.

I'm personally not keen on removing the "et al." string, and I don't recommend it, but a recent version of biblatex allows you to do so, if you really wish, in a consistent manner.

Note I have changed your style=alphabetic,citestyle=authoryear to style=authoryear. Mixing those styles, though technically "works", is bound to give you some inconsistencies or sub optimal results.

\documentclass{beamer}

\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}

\usepackage{filecontents}

\begin{filecontents}{bibfile.bib}
  @article{LEGUENNEC2018,
    author = "Le Guennec, Yves
              and Brunet, Jean-Patrick
              and Daim, Fatima Zohra
              and Chau, Ming
              and Tourbier, Yves",
    title = "A parametric and non-intrusive reduced order model of car crash simulation",
    journal = "Computer Methods in Applied Mechanics and Engineering",
    year = "2018",
  }

  @article{LEGUENNEC2018_2,
    author = "Le Guennec, Yves",
    title = "Study 2 by le Guennec",
    journal = "A journal title",
    year = "2018",
  }

  @Article{Borzacchiello2017,
    author="Borzacchiello, Domenico
            and Aguado, Jos{\'e} V.
            and Chinesta, Francisco",
    title="Non-intrusive Sparse Subspace Learning for Parametrized Problems",
    journal="Archives of Computational Methods in Engineering",
    year = "2017",
  }

  @article{Goldfarb2014,
    author = "Goldfarb, Donald and Qin, Zhiwei",
    title = "Robust Low-Rank Tensor Recovery: Models and Algorithms",
    journal = "SIAM Journal on Matrix Analysis and Applications",
    year = "2014",
  }
\end{filecontents}

\usepackage[
  style=authoryear,
  maxcitenames=1,
  maxbibnames=99,
  giveninits=true,
  nohashothers=true,
  nosortothers=true,
  ]{biblatex}

\addbibresource{bibfile.bib}

\DefineBibliographyStrings{english}{andothers={}}

\begin{document}

\begin{frame}{Trial frame}
  \cite{Borzacchiello2017}

  \cite{LEGUENNEC2018}

  \cite{LEGUENNEC2018_2}

  \cite{Goldfarb2014}
\end{frame}

\begin{frame}[allowframebreaks]{References}
  \printbibliography
\end{frame}

\end{document}

Resulting in citations:

and references: