Make _nmod_poly_sin_series, _nmod_poly_cos_series wrap generics

Author: fredrik-johansson

doc/source/nmod_poly.rst

@@ -2431,23 +2431,19 @@ of polynomial multiplication.
 
     Set `g = \operatorname{asinh}(h) + O(x^n)`.
 
-.. function:: void _nmod_poly_sin_series(nn_ptr g, nn_srcptr h, slong n, nmod_t mod)
+.. function:: void _nmod_poly_sin_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod)
 
-    Set `g = \operatorname{sin}(h) + O(x^n)`. Assumes `n > 0` and that `h`
-    is zero-padded as necessary to length `n`. Aliasing of `g` and `h` is
-    allowed. The value is computed using the identity
-    `\sin(x) = 2 \tan(x/2)) / (1 + \tan^2(x/2)).`
+    Set `g = \operatorname{sin}(h) + O(x^n)`. Assumes `n > 0` and `hlen > 0`.
+    Aliasing of `g` and `h` is allowed.
 
 .. function:: void nmod_poly_sin_series(nmod_poly_t g, const nmod_poly_t h, slong n)
 
     Set `g = \operatorname{sin}(h) + O(x^n)`.
 
-.. function:: void _nmod_poly_cos_series(nn_ptr g, nn_srcptr h, slong n, nmod_t mod)
+.. function:: void _nmod_poly_cos_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod)
 
-    Set `g = \operatorname{cos}(h) + O(x^n)`. Assumes `n > 0` and that `h`
-    is zero-padded as necessary to length `n`. Aliasing of `g` and `h` is
-    allowed. The value is computed using the identity
-    `\cos(x) = (1-\tan^2(x/2)) / (1 + \tan^2(x/2)).`
+    Set `g = \operatorname{cos}(h) + O(x^n)`. Assumes `n > 0` and `hlen > 0`.
+    Aliasing of `g` and `h` is allowed.`
 
 .. function:: void nmod_poly_cos_series(nmod_poly_t g, const nmod_poly_t h, slong n)
 

src/nmod_poly.h

@@ -854,10 +854,10 @@ void nmod_poly_tan_series(nmod_poly_t g, const nmod_poly_t h, slong n);
 void _nmod_poly_asin_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod);
 void nmod_poly_asin_series(nmod_poly_t g, const nmod_poly_t h, slong n);
 
-void _nmod_poly_sin_series(nn_ptr g, nn_srcptr h, slong n, nmod_t mod);
+void _nmod_poly_sin_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod);
 void nmod_poly_sin_series(nmod_poly_t g, const nmod_poly_t h, slong n);
 
-void _nmod_poly_cos_series(nn_ptr g, nn_srcptr h, slong n, nmod_t mod);
+void _nmod_poly_cos_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod);
 void nmod_poly_cos_series(nmod_poly_t g, const nmod_poly_t h, slong n);
 
 void _nmod_poly_asinh_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod);

src/nmod_poly/trig_series.c

@@ -204,62 +204,36 @@ nmod_poly_cosh_series(nmod_poly_t g, const nmod_poly_t h, slong n)
 }
 
 void
-_nmod_poly_cos_series(nn_ptr g, nn_srcptr h, slong n, nmod_t mod)
+_nmod_poly_cos_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod)
 {
-    nn_ptr t, u;
-
-    t = _nmod_vec_init(n);
-    u = _nmod_vec_init(n);
-
-    /* cos(x) = (1-tan(x/2)^2)/(1+tan(x/2)^2) */
-    _nmod_vec_scalar_mul_nmod(u, h, n, n_invmod(UWORD(2), mod.n), mod);
-    _nmod_poly_tan_series(t, u, n, n, mod);
-    _nmod_poly_mullow(u, t, n, t, n, n, mod);
-    _nmod_vec_neg(t, u, n, mod);
-    t[0] = u[0] = UWORD(1);
-    _nmod_poly_div_series(g, t, n, u, n, n, mod);
-
-    _nmod_vec_clear(t);
-    _nmod_vec_clear(u);
+    gr_ctx_t ctx;
+    _gr_ctx_init_nmod(ctx, &mod);
+    GR_MUST_SUCCEED(_gr_poly_cos_series(g, h, hlen, n, ctx));
 }
 
 void
 nmod_poly_cos_series(nmod_poly_t g, const nmod_poly_t h, slong n)
 {
-    nn_ptr h_coeffs;
-    slong h_len = h->length;
+    slong hlen = h->length;
 
-    if (h_len > 0 && h->coeffs[0] != UWORD(0))
+    if (hlen > 0 && h->coeffs[0] != UWORD(0))
     {
         flint_throw(FLINT_ERROR, "Exception (nmod_poly_cos_series). Constant term != 0.\n");
     }
 
-    if (h_len == 1 || n < 2)
+    if (n <= 1 || hlen <= 1)
     {
-        nmod_poly_zero(g);
-        if (n > 0)
-            nmod_poly_set_coeff_ui(g, 0, UWORD(1));
+        if (n == 0)
+            nmod_poly_zero(g);
+        else
+            nmod_poly_one(g);
         return;
     }
 
     nmod_poly_fit_length(g, n);
-
-    if (h_len < n)
-    {
-        h_coeffs = _nmod_vec_init(n);
-        flint_mpn_copyi(h_coeffs, h->coeffs, h_len);
-        flint_mpn_zero(h_coeffs + h_len, n - h_len);
-    }
-    else
-        h_coeffs = h->coeffs;
-
-    _nmod_poly_cos_series(g->coeffs, h_coeffs, n, h->mod);
-
-    if (h_len < n)
-        _nmod_vec_clear(h_coeffs);
-
+    _nmod_poly_cos_series(g->coeffs, h->coeffs, hlen, n, h->mod);
     g->length = n;
-	_nmod_poly_normalise(g);
+    _nmod_poly_normalise(g);
 }
 
 void
@@ -329,58 +303,32 @@ nmod_poly_sinh_series(nmod_poly_t g, const nmod_poly_t h, slong n)
 }
 
 void
-_nmod_poly_sin_series(nn_ptr g, nn_srcptr h, slong n, nmod_t mod)
+_nmod_poly_sin_series(nn_ptr g, nn_srcptr h, slong hlen, slong n, nmod_t mod)
 {
-    nn_ptr t, u;
-
-    t = _nmod_vec_init(n);
-    u = _nmod_vec_init(n);
-
-    /* sin(x) = 2*tan(x/2)/(1+tan(x/2)^2) */
-    _nmod_vec_scalar_mul_nmod(u, h, n, n_invmod(2, mod.n), mod);
-    _nmod_poly_tan_series(t, u, n, n, mod);
-    _nmod_poly_mullow(u, t, n, t, n, n, mod); u[0] = UWORD(1);
-    _nmod_poly_div_series(g, t, n, u, n, n, mod);
-    _nmod_vec_add(g, g, g, n, mod);
-
-    _nmod_vec_clear(t);
-    _nmod_vec_clear(u);
+    gr_ctx_t ctx;
+    _gr_ctx_init_nmod(ctx, &mod);
+    GR_MUST_SUCCEED(_gr_poly_sin_series(g, h, hlen, n, ctx));
 }
 
 void
 nmod_poly_sin_series(nmod_poly_t g, const nmod_poly_t h, slong n)
 {
-    nn_ptr h_coeffs;
-    slong h_len = h->length;
+    slong hlen = h->length;
 
-    if (h_len > 0 && h->coeffs[0] != UWORD(0))
+    if (hlen > 0 && h->coeffs[0] != UWORD(0))
     {
         flint_throw(FLINT_ERROR, "Exception (nmod_poly_sin_series). Constant term != 0.\n");
     }
 
-    if (h_len == 1 || n < 2)
+    if (hlen <= 1 || n <= 1)
     {
         nmod_poly_zero(g);
         return;
     }
 
     nmod_poly_fit_length(g, n);
-
-    if (h_len < n)
-    {
-        h_coeffs = _nmod_vec_init(n);
-        flint_mpn_copyi(h_coeffs, h->coeffs, h_len);
-        flint_mpn_zero(h_coeffs + h_len, n - h_len);
-    }
-    else
-        h_coeffs = h->coeffs;
-
-    _nmod_poly_sin_series(g->coeffs, h_coeffs, n, h->mod);
-
-    if (h_len < n)
-        _nmod_vec_clear(h_coeffs);
-
-    g->length = n;
+    _nmod_poly_sin_series(g->coeffs, h->coeffs, hlen, n, h->mod);
+    _nmod_poly_set_length(g, n);
 	_nmod_poly_normalise(g);
 }