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SilverStat's avatar
SilverStat
Copper Contributor
Feb 24, 2023

Iterating a lambda function over an array

Hello,   I have added what I hope is a simplified version of the problem I am having here. Take this pair of matrices: The function I need is expected to behave as follows: Suppose I am inte...
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PeterBartholomew1's avatar
PeterBartholomew1
Silver Contributor
Feb 25, 2023

SilverStat 

This goes for the problem somewhat at a single hit and could possibly benefit from a little more modularisation using Lambda functions.

=LET(
    nodeTable,    TAKE(WRAPROWS(TOROW(stiffnessTable), 30), , 4),
    elementIndex, SEQUENCE(ROWS(nodeTable)),
    MAKEARRAY( 10, 10,
        LAMBDA(rowIndex, columnIndex,
            LET(
                rowFreedom,  BYROW(nodeTable, LAMBDA(nodeList, XMATCH(rowIndex, nodeList))),
                colFreedom,  BYROW(nodeTable, LAMBDA(nodeList, XMATCH(columnIndex, nodeList))),
                unfiltered,  HSTACK(elementIndex, rowFreedom, colFreedom),
                criterion,   BYROW(IFNA(unfiltered, 0), LAMBDA(f, AND(f))),
                returnValue, IF(
                    criterion,
                    INDEX(stiffnessTable, 6 * (elementIndex - 1) + rowFreedom + 1, colFreedom)
                ),
                SUM(returnValue)
            )
        )
    )
)

It uses a calculated index applied to the entire list of stiffness matrices.  By the way, how do you plan to invert the matrix equations?

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