-/**
- * Computes the Pa / (1 + z(-1)) or Qa / (1 - z(-1)) coefficients
- * needed for LSP to LPC conversion.
- * We only need to calculate the 6 first elements of the polynomial.
- *
- * @param lsp line spectral pairs in cosine domain
- * @param f [out] polynomial input/output as a vector
- *
- * TIA/EIA/IS-733 2.4.3.3.5-1/2
- */
-static void lsp2polyf(const double *lsp, double *f, int lp_half_order)