## 1107 Reputation

12 years, 101 days

## Remove one Array from another...

Maple 2018

How do I remove Array B from Array A? e.g.

A:=Array([1,2,3,4,5,6,7,8...1000]
B:=Array([3,6,9,12,15....])   assuming A contains all the elements of B.

to get [1,2,4,5,7,8,11....]

Also is it possible to do it in place?

## Problem with MutableSet...

Maple 2018

.I am testing out the MutableSet command, There seems to be a problem with the number of emements that can be operated on. When N =100000 things are ok. When N=1000000 (or there abouts) the process doesn't terminate last line. Uorks ok for sets. Using Maple 2018.2 on Win10 64bit.

 (1)

 (2)

 (3)

## efficient operation on sets...

Maple 2018

I have 2 questions here

1st I want to extend this set Ug3 := {1, 19, 23, 29} by repeatively subtracting 6 fron its elements. first pass should give

`Ug3 := (Ug3-~ 6) union Ug3  Ug3 := {-5, 1, 13, 17, 19, 23, 29}`

Now I dont want to add any elenments less than 6 so -5 need to go

Second pass produces

`Ug3 := (Ug3-~ 6) union Ug3                Ug3 := {-11, -5, 1, 7, 11, 13, 17, 19, 23, 29}`

Obiviously no elements less than 6 to be added on second pass either.

At this point there is no further elements that could be added to the set.

I am looking for an efficient method. I can use For loops and if then checks. The sets grow in length quickly. Repetition lengths are 6, 30 210, 2310,... I use sets because the numbers get ordered automaticially. Are sets efficient or should I use some form of table?

## How do I add and multiply combinations o...

Maple 2018

This should be simple but I am missing something. I want to sum the product of combinations of numbers.

I know I can assign values to a0...a[n-1]. But that isn't nice.

(n,k):= (5,4);
add(mul~(combinat:-choose([a(||)[](0..n-1)], k))) ; =a0*a1*a2*a3+a0*a1*a2*a4+a0*a1*a3*a4+a0*a2*a3*a4+a1*a2*a3*a4  which is correct.
add(mul~(combinat:-choose([(0..n-1)], k))) ;   #should be 24 but I get 0

## How to save procedures to a library?...

Maple 2018

I have asked this before but am still confused. I have a half-dozen procedures I want to save. Don't want them in a module/package. I am using windows 10.

I just can't get the syntax correct on this.

Obviously after saving restart and load to test.

```libname;
"C:\Program Files\Maple 2018\lib",

"C:\Users\Ronan\maple\toolbox\CodeBuilder\lib",

"C:\Users\Ronan\maple\toolbox\OEIS\lib",

"C:\Users\Ronan\maple\toolbox\personal\lib",

"C:\Users\Ronan\maple\toolbox\UTF8\lib"
libdir := "C:/Users/Ronan/maple/toolbox/personal/lib";
libdir := "C:/Users/Ronan/maple/toolbox/personal/lib"
NULL;

LibraryTools:-Save(Pedal, cat(kernelopts(homedir), "/maple/toolbox/personal/lib/Pedal.mpl"));
Error, (in LibraryTools:-Save) could not open `C:\Users\Ronan/maple/toolbox/personal/lib/Pedal.mpl\Pedal.m` for writing

```

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