# Writing down Mathematics with Arrays

1. Dec 19, 2009

### dimensionless

I know how to do basic matrix operations, but sometimes I do calculations on computers and do array operations. How do I write down array operations on paper? For example, say I have two matrices, A and B, and I want to multiply them element by element.

2. Dec 19, 2009

### rochfor1

3. Dec 19, 2009

### Integral

Staff Emeritus
What you really want is the ordinary product at the top of the linked wiki article.

4. Dec 19, 2009

### rochfor1

He seems to want to multiply them element-wise, which is was the Schur product is for.

5. Dec 19, 2009

### dimensionless

So if I take the Schur product of A and B to get C, do I write

$$A \cdot B = C$$

As far as notation goes, this looks exactly like a dot product.

6. Dec 19, 2009

### rochfor1

You can use whatever notation for you that you want. What's important is that you know you're talking about the Schur product. I've seen some people use $$A *_S B$$.