Mod poly and mpn_mod random generation

doc/source/fmpz.rst

@@ -266,6 +266,11 @@ should call :func:`flint_rand_clear` to clean up.
 
     Generates a random integer in the range `0` to `m - 1` inclusive.
 
+.. function:: void fmpz_randm_not_zero(fmpz_t f, flint_rand_t state, const fmpz_t m)
+
+    Generates a random integer in the range `1` to `m - 1` inclusive. Requires
+    `m \geq 2`, otherwise an exception is thrown.
+
 .. function:: void fmpz_randtest_mod(fmpz_t f, flint_rand_t state, const fmpz_t m)
 
     Generates a random integer in the range `0` to `m - 1` inclusive, with an

doc/source/fmpz_mod_poly.rst

@@ -218,6 +218,18 @@ Randomisation
     set to a random monic irreducible polynomial.
 
 
+.. function:: void fmpz_mod_poly_rand(fmpz_mod_poly_t f, flint_rand_t state, slong len, const fmpz_mod_ctx_t ctx)
+
+    Generates a random polynomial with length up to `len`, with uniformly chosen coefficients.
+
+.. function:: void fmpz_mod_poly_rand_monic(fmpz_mod_poly_t f, flint_rand_t state, slong len, const fmpz_mod_ctx_t ctx)
+
+    Generates a random monic polynomial with length `len`, with uniformly chosen coefficients.
+
+.. function:: void fmpz_mod_poly_rand_irreducible(fmpz_mod_poly_t f, flint_rand_t state, slong len, const fmpz_mod_ctx_t ctx)
+
+    Generates a random irreducible polynomial with up to the given length and where the coefficients
+    are generated uniformly.
 
 Attributes
 --------------------------------------------------------------------------------

doc/source/mpn_mod.rst

@@ -94,6 +94,11 @@ Context objects
 Basic operations and arithmetic
 -------------------------------------------------------------------------------
 
+
+.. function:: int mpn_mod_rand(nn_ptr res, flint_rand_t state, gr_ctx_t ctx)
+
+   Generates a coefficient uniformly between `0` and `MPN_MOD_CTX_MODULUS(ctx)` exclusive.
+
 .. function:: int mpn_mod_ctx_write(gr_stream_t out, gr_ctx_t ctx)
               void mpn_mod_ctx_clear(gr_ctx_t ctx)
               truth_t mpn_mod_ctx_is_field(gr_ctx_t ctx)

doc/source/nmod_poly.rst

@@ -223,14 +223,25 @@ Assignment and basic manipulation
 Randomization
 --------------------------------------------------------------------------------
 
+.. function:: void nmod_poly_rand(nmod_poly_t poly, flint_rand_t state, slong len)
+
+    Generates a random polynomial with length up to ``len`` and coefficients generated uniformly.
+
+.. function:: void nmod_poly_rand_monic(nmod_poly_t poly, flint_rand_t state, slong len)
+
+    Generates a random monic polynomial of length ``len`` and non-leading coefficients generated uniformly.
+
+.. function:: void nmod_poly_rand_irreducible(nmod_poly_t poly, flint_rand_t state, slong len)
+
+    Generates a random irreducible polynomial with length up to ``len`` with coefficients generated uniformly.
 
 .. function:: void nmod_poly_randtest(nmod_poly_t poly, flint_rand_t state, slong len)
 
-    Generates a random polynomial with length up to ``len``.
+    Generates a random polynomial with length up to ``len``, sparse with increased probability, and with coefficients generated by :func:`n_randtest`. This function is intended for use in test code.
 
 .. function:: void nmod_poly_randtest_monic(nmod_poly_t poly, flint_rand_t state, slong len)
 
-    Generates a random monic polynomial with length ``len``.
+    Generates a random monic polynomial with length ``len``. For each coefficient the probability of some special values is increased (see :func:`n_randtest`). In particular, the polynomial is sparse with increased probability. This function is intended for use in test code.
 
 .. function:: void nmod_poly_randtest_trinomial(nmod_poly_t poly, flint_rand_t state, slong len)
 

doc/source/nmod_poly_mat.rst

@@ -169,10 +169,13 @@ Random matrix generation
 --------------------------------------------------------------------------------
 
 
+.. function:: void nmod_poly_mat_rand(nmod_poly_mat_t mat, flint_rand_t state, slong len)
+
+    Generates a matrix of polynomials with uniformly generated coefficients.
+
 .. function:: void nmod_poly_mat_randtest(nmod_poly_mat_t mat, flint_rand_t state, slong len)
 
-    This is equivalent to applying ``nmod_poly_randtest`` to all entries
-    in the matrix.
+    Generates a matrix of polynomials sparse with an increased probability. It is equivalent to apply ``nmod_poly_randtest`` to all entries in the matrix.
 
 .. function:: void nmod_poly_mat_randtest_sparse(nmod_poly_mat_t A, flint_rand_t state, slong len, float density)
 

src/fmpz.h

@@ -112,6 +112,7 @@ int _fmpz_is_canonical(const fmpz_t x);
 void fmpz_randbits_unsigned(fmpz_t f, flint_rand_t state, flint_bitcnt_t bits);
 void fmpz_randbits(fmpz_t f, flint_rand_t state, flint_bitcnt_t bits);
 void fmpz_randm(fmpz_t f, flint_rand_t state, const fmpz_t m);
+void fmpz_randm_not_zero(fmpz_t f, flint_rand_t state, const fmpz_t m);
 void fmpz_randtest(fmpz_t f, flint_rand_t state, flint_bitcnt_t bits);
 void fmpz_randtest_unsigned(fmpz_t f, flint_rand_t state, flint_bitcnt_t bits);
 void fmpz_randtest_not_zero(fmpz_t f, flint_rand_t state, flint_bitcnt_t bits);

src/fmpz/rand.c

@@ -80,6 +80,20 @@ fmpz_randm(fmpz_t f, flint_rand_t state, const fmpz_t m)
     }
 }
 
+void
+fmpz_randm_not_zero(fmpz_t f, flint_rand_t state, const fmpz_t m)
+{
+    if (fmpz_cmp_ui(m, 2) < 0)
+    {
+        flint_throw(FLINT_ERROR, "Exception (fmpz_randm_not_zero). m < 2.\n");
+    }
+    fmpz_t mMinusOne;
+    fmpz_sub_ui(mMinusOne, m, 1);
+
+    fmpz_randm(f, state, mMinusOne); /* 0..m-2 */
+    fmpz_add_ui(f, f, 1); /* 1..m-1 */
+}
+
 void fmpz_randprime(fmpz_t f, flint_rand_t state, flint_bitcnt_t bits, int proved)
 {
     if (bits <= FLINT_BITS)

src/fmpz_mod_poly.h

@@ -134,6 +134,15 @@ int fmpz_mod_poly_is_canonical(const fmpz_mod_poly_t A, const fmpz_mod_ctx_t ctx
 
 
 /*  Randomisation ************************************************************/
+void fmpz_mod_poly_rand(fmpz_mod_poly_t f, flint_rand_t state,
+                                          slong len, const fmpz_mod_ctx_t ctx);
+
+void fmpz_mod_poly_rand_monic(fmpz_mod_poly_t f,
+                      flint_rand_t state, slong len, const fmpz_mod_ctx_t ctx);
+
+void fmpz_mod_poly_rand_irreducible(fmpz_mod_poly_t f,
+                      flint_rand_t state, slong len, const fmpz_mod_ctx_t ctx);
+
 
 void fmpz_mod_poly_randtest(fmpz_mod_poly_t f, flint_rand_t state,
                                           slong len, const fmpz_mod_ctx_t ctx);

src/fmpz_mod_poly/randtest.c

@@ -17,7 +17,7 @@
 #include "fmpz_mod_poly.h"
 #include "fmpz_mod_poly_factor.h"
 
-void fmpz_mod_poly_randtest(fmpz_mod_poly_t f, flint_rand_t state, slong len,
+void fmpz_mod_poly_rand(fmpz_mod_poly_t f, flint_rand_t state, slong len,
                                                       const fmpz_mod_ctx_t ctx)
 {
     slong i;
@@ -31,7 +31,7 @@ void fmpz_mod_poly_randtest(fmpz_mod_poly_t f, flint_rand_t state, slong len,
     _fmpz_mod_poly_normalise(f);
 }
 
-void fmpz_mod_poly_randtest_monic(fmpz_mod_poly_t f, flint_rand_t state,
+void fmpz_mod_poly_rand_monic(fmpz_mod_poly_t f, flint_rand_t state,
                                            slong len, const fmpz_mod_ctx_t ctx)
 {
     slong i;
@@ -48,6 +48,53 @@ void fmpz_mod_poly_randtest_monic(fmpz_mod_poly_t f, flint_rand_t state,
     _fmpz_mod_poly_set_length(f, len);
 }
 
+void fmpz_mod_poly_rand_irreducible(fmpz_mod_poly_t f, flint_rand_t state,
+                                           slong len, const fmpz_mod_ctx_t ctx)
+{
+    if (len == 0)
+    {
+        flint_throw(FLINT_ERROR, "Exception (fmpz_mod_poly_rand_irreducible). len == 0.\n");
+    }
+
+    do {
+        fmpz_mod_poly_rand(f, state, len, ctx);
+    } while (fmpz_mod_poly_is_zero(f, ctx) ||
+             !fmpz_mod_poly_is_irreducible(f, ctx));
+}
+
+void fmpz_mod_poly_randtest(fmpz_mod_poly_t f, flint_rand_t state, slong len,
+                                                      const fmpz_mod_ctx_t ctx)
+{
+    slong i;
+
+    fmpz_mod_poly_fit_length(f, len, ctx);
+
+    for (i = 0; i < len; i++) {
+        fmpz_randtest_mod(f->coeffs + i, state, fmpz_mod_ctx_modulus(ctx));
+    }
+
+    _fmpz_mod_poly_set_length(f, len);
+    _fmpz_mod_poly_normalise(f);
+}
+
+void fmpz_mod_poly_randtest_monic(fmpz_mod_poly_t f, flint_rand_t state,
+                                           slong len, const fmpz_mod_ctx_t ctx)
+{
+    slong i;
+
+    FLINT_ASSERT(len > 0);
+
+    fmpz_mod_poly_fit_length(f, len, ctx);
+
+    for (i = 0; i < len - 1; i++) {
+        fmpz_randtest_mod(f->coeffs + i, state, fmpz_mod_ctx_modulus(ctx));
+    }
+
+    fmpz_one(f->coeffs + len - 1);
+
+    _fmpz_mod_poly_set_length(f, len);
+}
+
 static void
 fmpz_mod_poly_randtest_monic_sparse(fmpz_mod_poly_t poly, flint_rand_t state,
                             slong len, slong nonzero, const fmpz_mod_ctx_t ctx)
@@ -56,10 +103,11 @@ fmpz_mod_poly_randtest_monic_sparse(fmpz_mod_poly_t poly, flint_rand_t state,
 
     fmpz_mod_poly_fit_length(poly, len, ctx);
     _fmpz_vec_zero(poly->coeffs, len);
-    fmpz_randm(poly->coeffs + 0, state, fmpz_mod_ctx_modulus(ctx));
-    for (i = 1; i < nonzero; i++)
-       fmpz_randm(poly->coeffs + n_randint(state, len - 1) + 1,
-                                             state, fmpz_mod_ctx_modulus(ctx));
+    fmpz_randtest_mod(poly->coeffs + 0, state, fmpz_mod_ctx_modulus(ctx));
+    for (i = 1; i < nonzero; i++) {
+       ulong random_idx = n_randint(state, len - 1);
+       fmpz_randtest_mod(poly->coeffs + random_idx + 1, state, fmpz_mod_ctx_modulus(ctx));
+    }
     fmpz_set_ui(poly->coeffs + len - 1, 1);
     _fmpz_mod_poly_set_length(poly, len);
 }
@@ -127,22 +175,23 @@ void fmpz_mod_poly_randtest_trinomial(fmpz_mod_poly_t poly,
     ulong k;
     fmpz_mod_poly_fit_length(poly, len, ctx);
     _fmpz_vec_zero(poly->coeffs, len);
-    fmpz_randm(poly->coeffs, state, fmpz_mod_ctx_modulus(ctx));
+    fmpz_randtest_mod(poly->coeffs, state, fmpz_mod_ctx_modulus(ctx));
     k = (n_randtest(state) % (len - 2)) + 1;
-    fmpz_randm(poly->coeffs + k, state, fmpz_mod_ctx_modulus(ctx));
+    fmpz_randtest_mod(poly->coeffs + k, state, fmpz_mod_ctx_modulus(ctx));
     fmpz_one(poly->coeffs + len - 1);
     _fmpz_mod_poly_set_length(poly, len);
 }
 
 void fmpz_mod_poly_randtest_pentomial(fmpz_mod_poly_t poly,
                        flint_rand_t state, slong len, const fmpz_mod_ctx_t ctx)
 {
+    const fmpz * modulus = fmpz_mod_ctx_modulus(ctx);
     fmpz_mod_poly_fit_length(poly, len, ctx);
     _fmpz_vec_zero(poly->coeffs, len);
-    fmpz_randm(poly->coeffs, state, fmpz_mod_ctx_modulus(ctx));
-    fmpz_randm(poly->coeffs + 1, state, fmpz_mod_ctx_modulus(ctx));
-    fmpz_randm(poly->coeffs + 2, state, fmpz_mod_ctx_modulus(ctx));
-    fmpz_randm(poly->coeffs + 3, state, fmpz_mod_ctx_modulus(ctx));
+    fmpz_randtest_mod(poly->coeffs, state, modulus);
+    fmpz_randtest_mod(poly->coeffs + 1, state, modulus);
+    fmpz_randtest_mod(poly->coeffs + 2, state, modulus);
+    fmpz_randtest_mod(poly->coeffs + 3, state, modulus);
     fmpz_one(poly->coeffs + len - 1);
     _fmpz_mod_poly_set_length(poly, len);
 }

src/mpn_mod.h

@@ -126,6 +126,7 @@ int mpn_mod_neg_one(nn_ptr res, gr_ctx_t ctx);
 int mpn_mod_set_mpn(nn_ptr res, nn_srcptr x, slong xn, gr_ctx_t ctx);
 int mpn_mod_set_fmpz(nn_ptr res, const fmpz_t x, gr_ctx_t ctx);
 int mpn_mod_set_other(nn_ptr res, gr_ptr v, gr_ctx_t v_ctx, gr_ctx_t ctx);
+int mpn_mod_rand(nn_ptr res, flint_rand_t state, gr_ctx_t ctx);
 int mpn_mod_randtest(nn_ptr res, flint_rand_t state, gr_ctx_t ctx);
 int mpn_mod_write(gr_stream_t out, nn_srcptr x, gr_ctx_t ctx);
 
@@ -191,6 +192,7 @@ int mpn_mod_div(nn_ptr res, nn_srcptr x, nn_srcptr y, gr_ctx_t ctx);
 int _mpn_mod_vec_zero(nn_ptr res, slong len, gr_ctx_t ctx);
 int _mpn_mod_vec_clear(nn_ptr FLINT_UNUSED(res), slong FLINT_UNUSED(len), gr_ctx_t FLINT_UNUSED(ctx));
 int _mpn_mod_vec_set(nn_ptr res, nn_srcptr x, slong len, gr_ctx_t ctx);
+int _mpn_mod_vec_rand(nn_ptr res, flint_rand_t state, slong len, gr_ctx_t ctx);
 void _mpn_mod_vec_swap(nn_ptr vec1, nn_ptr vec2, slong len, gr_ctx_t ctx);
 int _mpn_mod_vec_neg(nn_ptr res, nn_srcptr x, slong len, gr_ctx_t ctx);
 int _mpn_mod_vec_add(nn_ptr res, nn_srcptr x, nn_srcptr y, slong len, gr_ctx_t ctx);

src/mpn_mod/ring.c

@@ -203,6 +203,18 @@ mpn_mod_set_other(nn_ptr res, gr_ptr v, gr_ctx_t v_ctx, gr_ctx_t ctx)
     return gr_generic_set_other(res, v, v_ctx, ctx);
 }
 
+int
+mpn_mod_rand(nn_ptr res, flint_rand_t state, gr_ctx_t ctx)
+{
+    fmpz_t t;
+    fmpz_init(t);
+    fmpz_set_ui_array(t, MPN_MOD_CTX_MODULUS(ctx), MPN_MOD_CTX_NLIMBS(ctx));
+    fmpz_randm(t, state, t);
+    GR_IGNORE(mpn_mod_set_fmpz(res, t, ctx));
+    fmpz_clear(t);
+    return GR_SUCCESS;
+}
+
 int
 mpn_mod_randtest(nn_ptr res, flint_rand_t state, gr_ctx_t ctx)
 {

src/mpn_mod/vec.c

@@ -32,6 +32,19 @@ _mpn_mod_vec_set(nn_ptr res, nn_srcptr x, slong len, gr_ctx_t ctx)
     return GR_SUCCESS;
 }
 
+int
+_mpn_mod_vec_rand(nn_ptr res, flint_rand_t state, slong len, gr_ctx_t ctx)
+{
+    slong n = MPN_MOD_CTX_NLIMBS(ctx);
+    slong i;
+
+    for (i = 0; i < len; i++)
+        if (mpn_mod_rand(res + i * n, state, ctx) != GR_SUCCESS)
+            return GR_UNABLE;
+
+    return GR_SUCCESS;
+}
+
 void
 _mpn_mod_vec_swap(nn_ptr vec1, nn_ptr vec2, slong len, gr_ctx_t ctx)
 {

src/nmod_poly.h

@@ -227,6 +227,10 @@ int nmod_poly_is_monic(const nmod_poly_t poly)
 
 /* Randomisation  ************************************************************/
 
+void nmod_poly_rand(nmod_poly_t poly, flint_rand_t state, slong len);
+void nmod_poly_rand_monic(nmod_poly_t poly, flint_rand_t state, slong len);
+void nmod_poly_rand_irreducible(nmod_poly_t poly, flint_rand_t state, slong len);
+
 void nmod_poly_randtest(nmod_poly_t poly, flint_rand_t state, slong len);
 
 NMOD_POLY_INLINE

src/nmod_poly/randtest.c

@@ -14,6 +14,34 @@
 #include "nmod_poly.h"
 #include "nmod_poly_factor.h"
 
+/* rand functions -> coefficients generated uniformly */
+void
+nmod_poly_rand(nmod_poly_t poly, flint_rand_t state, slong len)
+{
+    nmod_poly_fit_length(poly, len);
+    _nmod_vec_rand(poly->coeffs, state, len, poly->mod);
+    poly->length = len;
+    _nmod_poly_normalise(poly);
+}
+
+void
+nmod_poly_rand_monic(nmod_poly_t poly, flint_rand_t state, slong len)
+{
+    nmod_poly_fit_length(poly, len);
+    _nmod_vec_rand(poly->coeffs, state, len - 1, poly->mod);
+    poly->coeffs[len - 1] = 1;
+    poly->length = len;
+}
+
+void
+nmod_poly_rand_irreducible(nmod_poly_t poly, flint_rand_t state, slong len)
+{
+    do {
+        nmod_poly_rand(poly, state, len);
+    } while (nmod_poly_is_zero(poly) || !(nmod_poly_is_irreducible(poly)));
+}
+
+// Randtest functions -> dense/sparse polynomials
 void
 nmod_poly_randtest(nmod_poly_t poly, flint_rand_t state, slong len)
 {

src/nmod_poly_mat.h

@@ -141,6 +141,7 @@ void nmod_poly_mat_one(nmod_poly_mat_t mat);
 
 /* Random matrices ***********************************************************/
 
+void nmod_poly_mat_rand(nmod_poly_mat_t A, flint_rand_t state, slong len);
 void nmod_poly_mat_randtest(nmod_poly_mat_t mat, flint_rand_t state,
                                 slong len);
 

src/nmod_poly_mat/rand.c

@@ -12,6 +12,17 @@
 #include "nmod_poly.h"
 #include "nmod_poly_mat.h"
 
+void
+nmod_poly_mat_rand(nmod_poly_mat_t A, flint_rand_t state, slong len)
+{
+    slong i, j;
+
+    for (i = 0; i < A->r; i++)
+        for (j = 0; j < A->c; j++)
+            nmod_poly_rand(nmod_poly_mat_entry(A, i, j), state, len);
+}
+
+
 void
 nmod_poly_mat_randtest(nmod_poly_mat_t A, flint_rand_t state, slong len)
 {

src/nmod_vec.h

@@ -46,7 +46,6 @@ void _nmod_vec_clear(nn_ptr vec)
 }
 
 void _nmod_vec_randtest(nn_ptr vec, flint_rand_t state, slong len, nmod_t mod);
-
 void _nmod_vec_rand(nn_ptr vec, flint_rand_t state, slong len, nmod_t mod);
 
 NMOD_VEC_INLINE