int tri_sylvester_solve(const matrix_t *R, matrix_t *C) {
  int i,j,k = 0;
  if(R->m != R->n | C->m != R->n | C->n != R->n){
    return -2;
  }


  //algorithm starts
  for(k = 0; k < C->n; k++){
    for(j = 0; j < k; j++) {
      for(i = 0; i < C->n; i++) {
          if(!C->A[k][i]) {
            return -2;
          }
          C->A[k][i] -=  C->A[j][i]*R->A[j][k];
        }
      }
    if(!C->A[k][k]) {
      return -2;
    }
    if(R->A[k][k] == 0){
      return -1;
    }
    else if (R->A[k][k] != R->A[k][k]){
      return -1;
    }
    else if (R->A[k][k] > pow(10,300) | R->A[k][k] < -pow(10,300)){
      return -1;
    }
    fwsubst(C->m,R->A[k][k],R->A,C->A[k]);
  }

  for(k = 0; k < C->n; k++){
    for(j = 0; j < C->n; j++) {
        printf("C = %f\n",C->A[j][k]);
      }
  }
  return 0;
}