KernelEvaluate

KernelEvaluate[expr]

evaluates expr in the Wolfram Language kernel, even when called from compiled code.

KernelEvaluate[x,expr]

captures the value of the compiled variable x for use in the evaluation of expr.

KernelEvaluate[{x1,x2,…},expr]

captures the values of the xi for use in the evaluation of expr.

Details

  • The expression expr in KernelEvaluate[expr] can use Wolfram Language functions or definitions given by the user.
  • The compiled variables such as x in KernelEvaluate[x,expr] are bound lexically as they are in Function.
  • In KernelEvaluate[x, expr], the evaluation of expr cannot modify the value of x.
  • Typically, KernelEvaluate is wrapped in TypeHint to specify the type of the result.

Examples

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Basic Examples  (3)

Use the Wolfram Engine evaluator to compute the AiryAi function from compiled code:

Execute the compiled function:

The result compares with the direct call:

Define a function in the Wolfram Engine:

Call the function from compiled code:

Use a local variable in compiled code:

The result compares with the direct call:

Scope  (4)

Use the result of KernelEvaluate as a function using an "InertExpression" type:

KernelEvaluate allows operations such as Fit to be integrated into the compiler:

Use KernelEvaluate to integrate file operations:

A function called from compiled code does not have to be defined when FunctionCompile is used:

It must be defined for the compiled code to run:

The definition can be changed and the new version will be used:

If there is no definition, there will be a runtime error:

Possible Issues  (2)

A runtime error happens if the output of KernelEvaluate does not match its declared type:

Variables given in KernelEvaluate are bound lexically and not dynamically:

This results in a runtime error because binding is lexical:

Neat Examples  (1)

Integrate NDSolve into compiled code:

Wolfram Research (2023), KernelEvaluate, Wolfram Language function, https://reference.wolfram.com/language/ref/KernelEvaluate.html.

Text

Wolfram Research (2023), KernelEvaluate, Wolfram Language function, https://reference.wolfram.com/language/ref/KernelEvaluate.html.

CMS

Wolfram Language. 2023. "KernelEvaluate." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/KernelEvaluate.html.

APA

Wolfram Language. (2023). KernelEvaluate. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/KernelEvaluate.html

BibTeX

@misc{reference.wolfram_2024_kernelevaluate, author="Wolfram Research", title="{KernelEvaluate}", year="2023", howpublished="\url{https://reference.wolfram.com/language/ref/KernelEvaluate.html}", note=[Accessed: 18-November-2024 ]}

BibLaTeX

@online{reference.wolfram_2024_kernelevaluate, organization={Wolfram Research}, title={KernelEvaluate}, year={2023}, url={https://reference.wolfram.com/language/ref/KernelEvaluate.html}, note=[Accessed: 18-November-2024 ]}