generic ASCII reader

Duvert

Is there a way to represent missing values in a .hwascii file that contains multiple scalar results?

I tried leaving blank fields for elements that do not have a value for a specific result. However, it seems that HyperView does not interpret empty fields correctly. Instead, it shifts to the next available value in the array.

For example:

ALTAIR ASCII FILE
$TITLE = STATIC ANALYSIS MS
$BINDING = ELEMENT
$COLUMN_INFO = ENTITY_ID
$RESULT_TYPE = lc_ALL_COSH,lc_ALL_COSH-0,lc_ALL_STRE_T,lc_ALL_STRE_T-0

100000,10.0,,10.0,
113190,0.714,,,0.714

In this case, HyperView displays the values for lc_ALL_COSH correctly. However, for lc_ALL_COSH-0, it reads the next non-empty value, causing the remaining results to be misaligned and leaving some result fields empty because those values have already been assigned to the wrong result type.

Is there a specific placeholder (such as NaN, or another keyword) that should be used for missing scalar values in a .hwascii file?

amriga

Hello Duvert,

In the Altair ASCII (.hwascii) format, HyperView expects a value for every result component defined in the $RESULT_TYPE header for each entity. Leaving a field blank (e.g., ,,) causes the reader to skip the empty space and parse the next available string, leading to the data misalignment you observed [Source: /uploads/39285-this-article-gives-an-overview-and-examples-of-altair-ascii-format-which-can-leveraged-to-read-custom-results-formats-generated-by-in-house-or-propriety-codes.md].

To represent missing or invalid scalar values without shifting the data, you should use the following approach:

1. Use `NaN` as a Placeholder

The standard keyword for representing "Not a Number" or missing data in HyperWorks result files is NaN. When HyperView encounters NaN in a .hwascii file, it treats the value as invalid or missing for that specific entity and result type.

2. Rules for Data Alignment

• Comma Consistency: Ensure that the number of commas matches the number of columns defined in $RESULT_TYPE plus the ENTITY_ID.
• No Blank Fields: Every position between commas must contain either a valid numeric value or the NaN string.
• Trailing Commas: If the last result in a line is missing, you must still provide NaN before the end of the line (or before the final comma if your format uses trailing delimiters).

3. Visualization in HyperView

When NaN is used:

• Contour Plots: The entities with NaN values will typically be shown in the "Legend" under a "N/A" or "Invalid" category, or they will not be colored if they fall outside the result range.
• Query Tool: The value will be reported as NaN or N/A.

For complex conversions or large datasets, it is recommended to use Altair Compose (OML or Python scripts) to generate .hwascii files, as it handles the formatting rules and placeholder insertion automatically

Source: https://community.altair.com/discussion/39285/this-article-gives-an-overview-and-examples-of-altair-ascii-format-which-can-leveraged-to-read-custom-results-formats-generated-by-in-house-or-propriety-codes

https://help.altair.com/hwdesktop/hwd/topics/reference/hwdref/rules_guidelines_r.htm