Dr. Patrick T

## 2088 Reputation

14 years, 96 days

## Round Matrix with non-numeric elements...

Maple

I wrote a procedure which rounds floats to a specified precision. I would like to apply it to a Matrix/List/Array/Vector that contains non-numeric cells as well as floats. I'm stuck at the type-checking stage.

# Round0 works on floats and lists and Matrices of floats:
restart;
Round0 := proc(x,n::integer:=1)
parse~(sprintf~(cat("%.",n,"f"),x));
end proc:

Round0(1.23456789);
1.2

Round0([1.23456789,9.87654321],2);
[1.23, 9.88]

## recolor from Hex...

I would like to recolor a list of plots using Maple default values. I have produced a list of colors with the plots:-setcolors(default) command. However, the colors are returned as a list of Hex values.  I first converted the Hex values to RGB values and then attempted to adapt a procedure written by Joe Riel, named -recolor- (refer to Joe's answer from which this question is branched).

But I must have done something wrong.

The conversion from Hex to RGB...

## Unprotect This, Unprotect That...

Maple

Maple has a number of protected names that cannot be redefined without some work.

A common request is to use the letter j or J instead of the default I for the imaginary unit. Also common is to be able to use the letter I as an ordinary variable, rather than as an imaginary unit. For this, there is a very convenient interface command.

restart;

(-1)^(1/2);

I

interface(imaginaryunit=J):
(-1)^(1/2);

J

(There...

## closing statements with fi and od...

Maple

In some cases if not always, "fi" can be used to close an "if" clause, instead of "end if" and "od" can be used to close a "do" clause, instead of "end do".

These short forms are intuitive and can save a lot of space; for instance say you have 5 "do" clauses to be closed, it is a lot shorter to type "od:od:od:od:od:" than  "end do:end do:end do:end do:end do:"

Yet for some reason it does not seem to be a recommended short form. The Advaced Programming Guide (dated 2008...

## Maximize expression with RootOf and para...

Maple

I have equations of the form x=max( f(x,u,E) ), where x is the unknown "variable" to solve for, where u is the "control" variable that can be selected to maximize f, and where E is a parameter. These are all real, positive scalars on [0,1].

One of my objectives is to plot x against E, for those values of u that solve the maximization. In my problem, the optimal values of u are expected to be unique for a given value of E.

My approach was to define...

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