9

I know how to simulate a 2d array in a linear array using [x + y * width] as a linear index.

I can extend this to 3d arrays: [x + y * width + z * width * height].

Is there a general formula for N-dimensional array?

I'm looking for a language-agnostic answer.

2 Answers 2

8

Sure. Just extending your example gives x + y*width + z*width*height + w*width*height*depth + ...

In other words, dim1 + dim2*size1 + dim3*size1*size2 + dim4*size1*size2*size3 + ...

Sign up to request clarification or add additional context in comments.

Comments

1

Eh, if you want some code... :-) C is language-agnostic enough, ya?

Assume input: location[dimensions]

Assume a table exists maxBound[dimensions] that contains the maximum boundaries of each dimension of the table.

int index = 0;
int multiplier = 1;
for (int i = 0;i < dimensions;i++)
{
  index += location[i] * multiplier;
  multiplier *= maxBound[i];
}

Your index will end up in the index field.

Test:
location = [3,4,5]
maxBound = [10,20,30]
loop initial: index = 0, multiplier = 1.
loop i=0: index = 3, multiplier = 10.
loop i=1: index = 43, multiplier = 200.
loop i=2: index = 1043, multipler = 6000.

I think this makes sense, but this is just coming out of the top of my head.

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.