flo-poly/src/calculus/bigint/b-differentiate.ts

A practical, root-focused JavaScript polynomial utility library.

/**  
 * Returns the result of differentiating the given polynomial.
 * 
 * @param p a polynomial with coefficients given densely as an array of bigints
 * from highest to lowest power, e.g. `[5n,-3n,0n]` represents the 
 * polynomial `5x^2 - 3x`
 * 
 * @example
 * ```typescript
 * bDifferentiate([5n, 4n, 3n, 2n, 1n]); //=> [20n, 12n, 6n, 2n]
 * ```
 * 
 * @doc
 */
function bDifferentiate(p: bigint[]): bigint[] {
	const r: bigint[] = [];
	
	const d = p.length - 1;
	for (let i=0; i<d; i++) {
		r.push(BigInt((d-i)) * p[i]);
	}
	
	return r;
}


export { bDifferentiate }