## Mike Mc Dermott

Michael McDermott

## 80 Reputation

17 years, 53 days
Self Employed
Circuit Analysis Engineer
Kokomo, Indiana, United States

## Equivalent to Pivot Table in Excel?...

Maple

Is there an equivalent to Pivot Table in Excel?
I'm working on some investing data, and am using Maple to gather information from various sources and using DataFrame to combine all the data. I could export the dataframe and open in Excel or other spreadsheet and use the Pivot table to summarize the data, but is there an easy way to do all of it in Maple?

Thanks

## Expression manipulation...

Maple

Is there a way to manipulate an equation so that it is in the form of (Expression of Primary Variables)*(Expression of Secondary Variables)
In the example below from Video 1: Fast Analytical Techniques for Electrical and Electronic Circuits (youtube.com), the primary variables are R1 and R2

PS. When I type ctrl-v to insert an image, I always get 2 copies.

## Expression Manipulation...

Maple

I have been inspired by videos at this site: (1) Vorperian's Electronic Circuits Courses - YouTube

In these lectures, he shows an example of calculating the resistance of 2 series pairs of resistors in parallel, which is given by

Eq1

This expression can be simplified, using the parallel operator (sometimes also referred to as the "reciprocal formula" or "harmonic sum") see Parallel (operator) - Wikipedia

`//` := (R1, R2) -> R2*R1/(R1 + R2)

Simplification
`//`(R1, R2)*`//`(R3, R4)     EQ 2

This is easier to understand EQ2 compared to EQ1
1. Is there a way to display the function as a binary operator as in R1`//`R2 ?

2. Is there a way to add the parallel operator to the simplification procedure?

The videos referenced above go into more complex expressions that I would like to explore, but this seems like the first step.

## Suggestion for storing data...

Maple

I would like to create a database of component information. I have previously done this using a table which is indexed by the part number. Each element is a DataFrame, which includes several items with values and at least 2 DataFrames. The 2 DataFrames are extracted from a Spreadsheet with 2 tabs, that is stored in a Maple Workbook. Each DataFrame has an name for the row and 2 columns; Description and Value. The Description is text and the value is a single value or 3-element list with unit. Such at [9, 10, 11]*~Unit('ohm')

Anyway, I'm wondering if this is the most efficient way. I'm also wondering if there is a way to create such a database so it can be used with other software tools, primarily Mathcad and Excel.

Thanks

## overcoming limitation of optimize functi...

Maple

According to the help page for optimize

"The optimize function makes use of Maple's option remember facility to identify common subexpressions in linear time and space. This means, however, that only those subexpressions which Maple has simplified to be identical are found. For example, the expression
"x + y"

is not recognized as being common to
"x + y + z"

. That is, optimize performs mainly "syntactic" optimizations."

Is there a way to more efficiently calculate a set of expressions that have common factors as in the example above?

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