Getting Started

This guide will help you get started with dynakw for reading and manipulating LS-DYNA keyword files.

Installation

Install dynakw using pip:

pip install dynakw

Basic Usage

Reading and Printing Keywords

To read a file and print all keywords:

import sys
from dynakw import DynaKeywordReader, KeywordType

with DynaKeywordReader('lsdyna_exa.k') as dkr:
    # Access all keywords
    for kw in dkr.keywords():
        kw.write(sys.stdout)

Reading Specific Keywords

You can filter and read specific keyword types:

import sys
from dynakw import DynaKeywordReader, KeywordType

with DynaKeywordReader('lsdyna_exa.k') as dkr:
    # Reading only NODE keywords
    for kw in dkr.find_keywords(KeywordType.NODE):
        kw.write(sys.stdout)

Understanding Keyword Structure

Each keyword has two main members:

• type - The keyword type (e.g., KeywordType.NODE, KeywordType.BOUNDARY_PRESCRIBED_MOTION)

• cards - Dictionary containing the data stored as numpy arrays following the LS-DYNA documentation

Modifying Keyword Data

You can modify data within keywords by accessing the cards dictionary. For example, to change a scale factor:

from dynakw import DynaKeywordReader, KeywordType

with DynaKeywordReader('lsdyna_exa.k') as dkr:
    for kw in dkr.keywords():
        # Modify data in a specific keyword
        if kw.type == KeywordType.BOUNDARY_PRESCRIBED_MOTION:
            kw.cards['Card 1']['SF'] = kw.cards['Card 1']['SF'] * 1.5

Saving Modified Files

After making changes, save the modified file:

from dynakw import DynaKeywordReader, KeywordType

with DynaKeywordReader('lsdyna_exa.k') as dkr:
    # Make your modifications
    for kw in dkr.keywords():
        if kw.type == KeywordType.BOUNDARY_PRESCRIBED_MOTION:
            kw.cards['Card 1']['SF'] = kw.cards['Card 1']['SF'] * 1.5

    # Save the edited file
    dkr.write('exa2.k')

Setting parameters (*PARAMETER) values

The library can be used to set the values of parameters inside a keyword file. The file must be saved afterwards for the setting to take effect.

To obtain the parameter names and values specified using *PARAMETER:

par_dict = dkr.parameters()

To change the parameter values:

# Configuration
input_file = 'test/full_files/parameter.k'
output_file = 'modified_parameters.k'

# Parameters to change (Name -> New Value)
parameters_to_change = {
    "rterm": 0.5,
    "istates": 100,
    "cpar2": "baz",
    "rplot": "term/(states-50) * 2.0"
}


with DynaKeywordReader(input_file) as dkr:
    dkr.set_parameters(parameters_to_change)

    dkr.write(output_file)

Using an LLM

The library is set up to work with the gemini LLM. One way of using an LLM to to download the code, start gemini inside the main directory, and asking gemini to create an example of what you need.

Next Steps

Now that you understand the basics, you can:

• Explore the API Reference for complete reference documentation

• Check out more examples for advanced use cases

• Learn about different keyword_types available in LS-DYNA