/**  
 * Returns the result of differentiating the given polynomial in double 
 * precision.
 * 
 * @param p a polynomial with coefficients given densely as an array of double
 * floating point numbers from highest to lowest power, e.g. `[5,-3,0]` 
 * represents the polynomial `5x^2 - 3x`
 * 
 * @example
 * ```typescript
 * differentiate([5, 4, 3, 2, 1]); //=> [20, 12, 6, 2]
 * ```
 * 
 * @doc
 */
function differentiate(p: number[]): number[] {
    const d = p.length - 1;
    if (d <= 0) { return []; }
    const result = new Array<number>(d);
    for (let i=0; i<d; i++) {
        result[i] = (d-i) * p[i];
    }
    
    return result;
}


export { differentiate }