creating a 8x8 matrix with only -1

i want to create a 8x8 matrix withn only the number -1 how do i do it?

Answer 1

[Torsten]

Use "ones" to build a matrix of ones and multiply it by (-1).

[Walter Roberson]

You have to be careful to build up the 8 x 8 size for the ones() call, out of pure -1's. It is certainly possible to do.

Answer 2

[埃博拉酱]

-ones(8)

Append at 20241029 as a Cody challenge:

rand(single('('-' ')) 
%You don't even need -1 in your code. This can be applied to any challenge that has a limit on the number that appears in the code.
%If you're okay with using characters that aren't on your keyboard, you can even just use a Backspace character (U+0008).

[Walter Roberson]

This uses 8, which violates the rule that only -1 can be used.

[Torsten]

@Walter Roberson

This is a very willful interpretation of the task. My guess was it's simply to create a 8x8 matrix of -1's.

[埃博拉酱]

Yes, any normal person would generate an 8×8 matrix of -1 all the way I wrote it. If you mean that the number that appears in the code can only have -1, I guess this is more appropriate as a Cody challenge rather than as a question in the Answers forum, which is more geared towards practical scenarios.

[DGM]

Excluding parentheses, arithmetic operators, and the output variable name, this uses nothing but negative ones (pun intended)

A = -ones((-1 + -1 + -1 + -1)*(-1 + -1))

A = 8×8

-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1

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[Walter Roberson]

@DGM

The + are not needed

A = -ones((-1 -1 -1 -1)*(-1 -1))

A = 8×8

-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1

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[DGM]

D'oh!

I must have had my blinders on when I was coming up with that.

Answer 3

[Aimee]

hey guys thanks for all the help i got it eventuallyt with the code A = -ones(8,8). just incase anyone sees this and need help in the future.

[Image Analyst]

Or you could simply do

A = [
    -1    -1    -1    -1    -1    -1    -1    -1 
    -1    -1    -1    -1    -1    -1    -1    -1 
    -1    -1    -1    -1    -1    -1    -1    -1 
    -1    -1    -1    -1    -1    -1    -1    -1 
    -1    -1    -1    -1    -1    -1    -1    -1 
    -1    -1    -1    -1    -1    -1    -1    -1 
    -1    -1    -1    -1    -1    -1    -1    -1 
    -1    -1    -1    -1    -1    -1    -1    -1 ]

though that's not a very MATLABy way of doing it, but it does use only -1's and no 8's.

[Walter Roberson]

This (Aimee's) solution involves the number 8, contrary to the requirement that the solution involves only -1

[埃博拉酱]

This shows that @Walter Roberson is over-reading OP's question. He just wants an 8×8 matrix of -1s.

[Walter Roberson]

@埃博拉酱

The requirement is "creating a 8x8 matrix with only -1" . Using an 8 in the command does not fit the requirement.

[Torsten]

@Walter Roberson

I'm not a native speaker, but isn't the usual interpretation of "creating a 8x8 matrix with only -1":

create a 8x8 matrix which has only -1's as elements

?

[DGM]

As a counterexample, "create fire with only flint and steel" typically does not imply that the fire contains either flint or steel. Maybe we're all wrong to be creating a matrix full of -1.

[Aimee]

no youre correct i wanted an 8x8 matrix where the only elements were -1 i managed it eventually with the formula i used above though.