R: Translate Stan model specification to C++ code

stanc {rstan} | R Documentation

## Translate Stan model specification to C++ code

### Description

Translate a model specification in Stan code to C++ code, which can then be compiled and loaded for sampling.

### Usage

      stanc(file, model_code = '', model_name = "anon_model", verbose = FALSE,
            obfuscate_model_name = TRUE, allow_undefined = FALSE,
            isystem = c(if (!missing(file)) dirname(file), getwd()))
      stanc_builder(file, isystem = c(dirname(file), getwd()),
                    verbose = FALSE, obfuscate_model_name = FALSE,
                    allow_undefined = FALSE)

### Arguments

`file` | A character string or a connection that R supports specifying the Stan model specification in Stan's modeling language.
`model_code` | Either a character string containing a Stan model specification or the name of a character string object in the workspace. This parameter is used only if parameter `file` is not specified, so it defaults to the empty string.
`model_name` | A character string naming the model. The default is `"anon_model"`. However, the model name will be derived from `file` or `model_code` (if `model_code` is the name of a character string object) if `model_name` is not specified.
`verbose` | Logical, defaulting to `FALSE`. If `TRUE` more intermediate information is printed during the translation procedure.
`obfuscate_model_name` | Logical, defaulting to `TRUE`, indicating whether to use a randomly-generated character string for the name of the C++ class. This prevents name clashes when compiling multiple models in the same R session.
`isystem` | A character vector naming a path to look for file paths in `file` that are to be included within the Stan program named by `file`. See the Details section below.
`allow_undefined` | A logical scalar defaulting to `FALSE` indicating whether to allow Stan functions to be declared but not defined in `file` or `model_code`. If `TRUE`, then it is the caller's responsibility to provide a function definition in another header file or linked shared object.

### Details

The `stanc_builder` function supports the standard C++ convention of specifying something like `#include "my_includes.txt"` on an entire line within the file named by the `file` argument. In other words, `stanc_builder` would look for `"my_includes.txt"` in (or under) the directories named by the `isystem` argument and — if found — insert its contents verbatim at that position before calling `stanc` on the resulting `model_code`. This mechanism reduces the need to copy common chunks of code across Stan programs. It is possible to include such files recursively.

Note that line numbers referred to in parser warnings or errors refer to the postprocessed Stan program rather than `file`. In the case of a parser error, the postprocessed Stan program will be printed after the error message. Line numbers referred to in messages while Stan is executing also refer to the postprocessed Stan program which can be obtained by calling `get_stancode`.

### Value

A list with named entries:

1. `model_name` Character string for the model name.

2. `model_code` Character string for the model's Stan specification.

3. `cppcode` Character string for the model's C++ code.

4. `status` Logical indicating success/failure (always `TRUE`) of translating the Stan code.

### Note

Unlike R, in which variable identifiers may contain dots (e.g. `a.1`), Stan prohibits dots from occurring in variable identifiers. Furthermore, C++ reserved words and Stan reserved words may not be used for variable names; see the Stan User's Guide for a complete list.

### References

The Stan Development Team Stan Modeling Language User's Guide and Reference Manual. http://mc-stan.org/.

The Stan Development Team CmdStan Interface User's Guide. http://mc-stan.org.

### See Also

`stan_model` and `stan`

### Examples

    stanmodelcode <- "
    data {
      int<lower=0> N;
      real y[N];
    }

    parameters {
      real mu;
    }

    model {
      mu ~ normal(0, 10);
      y ~ normal(mu, 1);
    }
    "

    r <- stanc(model_code = stanmodelcode, model_name = "normal1")
    str(r)

[Package rstan version 2.21.2 Index]