\theta = ( \pi_0, \beta_0, \beta_1 )\\
        f(x_i, z_i, \theta) = 1(z_i = 0) \pi_0 f_0(x_i) + 1(z_i=1)\pi_1 f_1 (x_i)

I keep getting these kind of errors, and notice it's always when I try to use a \begin inside another \begin. I am VERY new to LaTeX, just got told I have to use it for my final and have no experience.

I feel like I am fundamentally misunderstanding something about TeX.

  • 1
    Could you edit in the code with your preamble? align and align* should center their equations by default. If you just want multiple equations to be centered, use the gather environment (and you won't need to write \begin{center}...\end{center}). – Arun Debray Dec 12 '15 at 6:09
  • Editted it in with another example. – Jibril Dec 12 '15 at 6:18
  • If you want each line of a group of equations to be centered, don't use an align or align* environment; instead, use a gather or gather* environment.

  • Use the align and align* environments if you need to align the equations on some point, frequently an = symbol or other relational operator.

    Depending on the equations' content, it will in general be obvious if gather or align should be used.

  • Whatever else you do, do not use a center environment inside a gather or align environment. The center environment is meant for text-mode material only.

A separate issue: you may want to think about using different outputs for 1 depending on whether it's a simple digit or represents the indicator function. The amsmath package provides the instruction \DeclareMathOperator, which is used below to set up a macro called \One. (I know, not very imaginative...) In the example below, \One outputs a bold 1 symbol. You're of course free to choose a different output. For instance, if you wanted a "double-struck" (aka "blackboard bold") look, you could load the dsfont package and declare \DeclareMathOperator{\One}{\mathds{1}}.

enter image description here

\usepackage{amsmath} % for "align" and "gather" environments and "\DeclareMathOperator" macro
\DeclareMathOperator{\One}{\mathbf{1}} % symbol for indicator function

   \theta = ( \pi_0, \beta_0, \beta_1 )\\
   f(x_i, z_i, \theta) = \One(z_i = 0) \pi_0 f_0(x_i) + \One(z_i=1)\pi_1 f_1 (x_i)

   \theta &= ( \pi_0, \beta_0, \beta_1 )\\
   f(x_i, z_i, \theta) &= \One(z_i = 0) \pi_0 f_0(x_i) + \One(z_i=1)\pi_1 f_1 (x_i)

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.