void filter_mem2(float *x, spx_coef_t *num, spx_coef_t *den, float *y, int N, int ord,  spx_mem_t *mem)
void filter_mem2(spx_sig_t *x, spx_coef_t *num, spx_coef_t *den, spx_sig_t *y, int N, int ord,  spx_mem_t *mem)
void filter_mem2(float *x, spx_coef_t *num, spx_coef_t *den, float *y, int N, int ord,  spx_mem_t *mem){   int i,j;   float xi,yi;   for (i=0;i<N;i++)   {      xi=x[i];      y[i] = num[0]*xi + mem[0];      yi=y[i];      for (j=0;j<ord-1;j++)      {         mem[j] = mem[j+1] + num[j+1]*xi - den[j+1]*yi;      }      mem[ord-1] = num[ord]*xi - den[ord]*yi;   }}