## 234 Reputation

18 years, 163 days

## Adjoint Matrix formulated as permuted H...

Maple 2020

For a project I need to construct a large symbolic adjoint matrix, hoping it can be factored afterward into nice expressions.
In the worksheet, I present an adjoint matrix using permuted Hadamard products. What puzzles me is that only for even dimensions, I need to multiply it (elementwise) with a parity matrix. Okay, not a specific Maple question, but maybe someone can help me out.

## seq slower than proc ...

Maple 2020

I learned about Dodgson calculation of the determinant only recently (https://en.m.wikipedia.org/wiki/Dodgson_condensation).
I am only interested in symbolic expressions of the determinant.
Furthermore, I compared several methods. Not surprisingly, the build in method is the fastest. But why is the seq method slower than the proc method for the Dodgson method? Is there anything I could do to program it more efficiently?

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 > Dodgson := proc(M::Matrix)  MatrixDet(M); InnerMatrix(M) ^~ (-1) *~ MatrixDet(MatrixDet(M)); do if 1 < RowDimension(%) then InnerMatrix(`%%`) ^~ (-1) *~ MatrixDet(%); end if; until RowDimension(%) = 1; Trace(%): end proc:
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## multipliying nonconformable matrices sho...

Maple 2021

I made an error by trying to multiply two nonconformable matrices. I think, I should receive an error message. But in this example this did not occur.

Strange.mw

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Matrices nonconformable, Maple should give error message:

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hereafter results are correct: Matrices

nonconformable, therefore error messages appear.

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Error, (in LinearAlgebra:-Multiply) first matrix column dimension (16) <> second matrix row dimension (4)

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Error, (in LinearAlgebra:-Multiply) first matrix column dimension (16) <> second matrix row dimension (4)

## indexed versus symbol...

Maple

I don't know how to fix this. What's wrong? Is there an alternative way to include underscores in a cat command?

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## input for Hessian in package VectorCalcu...

Maple 2020

Using the VectorCalculus package in Maple 2020.2, the Jacobian does accept my target function, whereas the Hessian does not. Both the Jacobian and the Hessian need an algebraic expression for its input.

What can I do to make it work?

kind regards, Harry

vectorcalculus_question.mw

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