Picking List Elements Using a Logical List
The program BOOLLIST picks out elements from a source list based on a logical list (a list that consists of 0s and 1s). 0 represents FALSE (do not pick) and 1 represents TRUE (pick).
For more information and examples, see my last blog entry: http://edspi31415.blogspot.com/2015/08/hp-prime-picking-out-elements-using.html
Note, that weird looking L is not the L character, but is represents the small "L" character. This is accessed from [2nd], [stat] (list), OPS sub-menu, select B for "L" (the last option in this sub-menu). On this listing, I will bold the "L".
TI-84 Plus: BOOLLIST
Input "SOURCE LIST=",⌊A
Input "LOGICAL LIST=",⌊B
sum(⌊B)→S
S→dim(⌊C)
1→I
1→J
dim(⌊A)→A
dim(⌊B)→B
For(K,1,A)
If ⌊B(J)=1
Then
⌊A(K)→⌊C(I)
1+I→I
End
1+J→J
If J>B
1→J
End
Pause ⌊C
Matrix by Element Multiplication
In R, the multiplication operator (*) multiplies matrices element-by-element. To get the proper linear-algebra multiplication of matrices, use the %*% operator. The program MATMLEM implements the former method.
Example:
[A] = [[ 1, 2 ] [ 3, 4 ]]
[B] = [[ 4, 3 ] [ 2, 1 ]]
Running MATMELM returns the matrix [[ 4, 6 ][ 6, 4 ]].
Variables [H], [I], and [J] are used for calculations. Also, like BOOLLIST above, the weird looking L is not the L character, but is represents the small "L" character. This is accessed from [2nd], [stat] (list), OPS sub-menu, select B for "L" (the last option in this sub-menu). On this listing, I will bold the "L".
TI-84 Plus: MATMELM
Disp "MATRIX MULTIPLY"
Disp "BY ELEMENT"
Input "[H]=",[H]
Input "[I]=",[I]
dim([H])→⌊H
dim([I])→⌊I
If ⌊H(1)≠⌊I(1) or ⌊H(2)≠⌊I(2)
Then
Disp "INVALID"
Stop
End
[H]→[J]
For(H,1,⌊H(1))
For(I,1,⌊H(2))
[H](H,I)*[I](H,I)→[J](H,I)
End
End
DelVar ⌊H
DelVar ⌊I
Disp "[J]="
Pause [J]
The program BOOLLIST picks out elements from a source list based on a logical list (a list that consists of 0s and 1s). 0 represents FALSE (do not pick) and 1 represents TRUE (pick).
For more information and examples, see my last blog entry: http://edspi31415.blogspot.com/2015/08/hp-prime-picking-out-elements-using.html
Note, that weird looking L is not the L character, but is represents the small "L" character. This is accessed from [2nd], [stat] (list), OPS sub-menu, select B for "L" (the last option in this sub-menu). On this listing, I will bold the "L".
TI-84 Plus: BOOLLIST
Input "SOURCE LIST=",⌊A
Input "LOGICAL LIST=",⌊B
sum(⌊B)→S
S→dim(⌊C)
1→I
1→J
dim(⌊A)→A
dim(⌊B)→B
For(K,1,A)
If ⌊B(J)=1
Then
⌊A(K)→⌊C(I)
1+I→I
End
1+J→J
If J>B
1→J
End
Pause ⌊C
Matrix by Element Multiplication
In R, the multiplication operator (*) multiplies matrices element-by-element. To get the proper linear-algebra multiplication of matrices, use the %*% operator. The program MATMLEM implements the former method.
Example:
[A] = [[ 1, 2 ] [ 3, 4 ]]
[B] = [[ 4, 3 ] [ 2, 1 ]]
Running MATMELM returns the matrix [[ 4, 6 ][ 6, 4 ]].
Variables [H], [I], and [J] are used for calculations. Also, like BOOLLIST above, the weird looking L is not the L character, but is represents the small "L" character. This is accessed from [2nd], [stat] (list), OPS sub-menu, select B for "L" (the last option in this sub-menu). On this listing, I will bold the "L".
TI-84 Plus: MATMELM
Disp "MATRIX MULTIPLY"
Disp "BY ELEMENT"
Input "[H]=",[H]
Input "[I]=",[I]
dim([H])→⌊H
dim([I])→⌊I
If ⌊H(1)≠⌊I(1) or ⌊H(2)≠⌊I(2)
Then
Disp "INVALID"
Stop
End
[H]→[J]
For(H,1,⌊H(1))
For(I,1,⌊H(2))
[H](H,I)*[I](H,I)→[J](H,I)
End
End
DelVar ⌊H
DelVar ⌊I
Disp "[J]="
Pause [J]
If the program is hard to read, please let me know in the comments.
I am about half way through the R introduction programming course. Time flies by when you are having fun.
Eddie
This blog is property of Edward Shore. 2015.
