Matrix manipulation help

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Summary:

Storing a variable to a specific element of a matrix

Matrix manipulation help

Bagels (guest) 08 May 2016 23:54

Hello smart people,

So I'm working on a program that needs to modify individual elements of a matrix. Previously, I was using variables to store 9 bits of information but that took up a lot of memory. How would I take a variable and add/ store it to a certain element of a matrix depending on a keypress?

For example, if the 8 key was pressed, it would store N or X or whatever to the top middle element of [A], 3 key: X to bottom right, ect

- some specs: TI-83+, speed not critical, preferably small but also not critical.

Hopefully you calculator geniuses can help me. Thanks bunch.

Re: Matrix manipulation help

lirtosiast 09 May 2016 02:19

You can get the key code of a pressed key with getKey. Look at the key-codes, and you can see that the top-left number key, the 7, is code 72, and the bottom right, the 3, is 94. If we want to map this to 3x3 matrix coordinates, the tens digit minus 6 is the row, and the ones digit minus 1 is the column. You can get the tens digit using int(K.1, and the ones digit using 10fPart(K.1, where K is the key code. Therefore, to store N to a cell based on the key code:

//get and validate key code first
N->[A](int(K.1)-1,10fPart(K.1)-6

Adding is much the same, except that it's slightly faster and smaller to store the coordinates to variables first, since you access them twice in [cell]+N->[cell].

Bagels (guest) 10 May 2016 02:37

Aight thanks man. This really helps.