# Tag Info

### Speed up calculation of recursively defined list

a[i_] = i; b[i_] = -i; RecurrenceTable[{θ[i] == a[i] θ[i - 1] - b[i - 1]^2 θ[i - 2], θ[0] == 1, θ[1] == a[1]}, θ, {i, 1, 1000}]
• 45.8k

### Speed up calculation of recursively defined list

A common approach to speed recursive calculations like this is memoization. In Mathematica, this can be as simple as using the ...
• 4,190
1 vote

### Why association slows down compiled function in the following example?

SelDataAssociation is 3x slower because it calls SelDataCompiled 3 times. Are you looking for a convenient way to call your ...
Accepted

### Is there any way to speedup the list selection further?

This is quite fast. Does it compile too? (I haven't installed a compiler.) ...
• 30k

### How to speedup comparison in the following example?

If one avoids repetition and explicit iteration, then one get fast code without compiling: ...
• 10.8k
Accepted

### How to speedup comparison in the following example?

You forgot to inline the zmin. ...
• 56.7k
1 vote

### Speed up summation of many inverse matrices

Note: This answer is only for the $2\times 2$ case, and it uses the explicit formula for the matrix inverse. The same idea may also work for other small dimensions, which is the case that OP seems to ...
• 10.8k

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