Function leafCount

src/compute-engine/cost-function.ts:259–264

(expr: Expression)

    // Use a base cost similar to Sqrt
    nameCost = 5;
  } else if (['Multiply'].includes(name)) {
    // We want 2x to be less expensive than x + x, so if the first operand
    // is a small number coefficient, treat it as cheaper
    const fnExprMul = isFunction(expr) ? expr : undefined;
    const ops = fnExprMul?.ops ?? [];
    if (ops.length === 2 && isNumber(ops[0])) {
      // A numeral times something is a "coefficient" shape and is priced
      // near an `Add`, so that `2x` beats `x + x`.
      //