[gnumeric] NT_RADICAL: New function.

[Morten Welinder <mortenw src gnome org>]

commit 9c774f75638f3cb82b3f234872496be5b95e5422
Author: Morten Welinder <terra gnome org>
Date:   Fri Oct 12 14:51:19 2018 -0400

    NT_RADICAL: New function.

 NEWS                               |  1 +
 plugins/fn-numtheory/numtheory.c   | 36 ++++++++++++++++++++++++++++++++++++
 plugins/fn-numtheory/plugin.xml.in |  1 +
 3 files changed, 38 insertions(+)
---
diff --git a/NEWS b/NEWS
index bc0e66632..5c90f9e85 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,7 @@ Morten:
        * Fix problem with setting auto-func.  [#357]
        * Fix problem reading really old xls format.
        * Fix sheet filter problem.  [#359]
+       * New NT_RADICAL function.
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.43
diff --git a/plugins/fn-numtheory/numtheory.c b/plugins/fn-numtheory/numtheory.c
index f2ce4e0ef..247fb05b7 100644
--- a/plugins/fn-numtheory/numtheory.c
+++ b/plugins/fn-numtheory/numtheory.c
@@ -320,6 +320,39 @@ gnumeric_phi (GnmFuncEvalInfo *ei, GnmValue const * const *args)
 
 /* ------------------------------------------------------------------------- */
 
+static GnmFuncHelp const help_radical[] = {
+       { GNM_FUNC_HELP_NAME, F_("NT_RADICAL:Radical function")},
+       { GNM_FUNC_HELP_ARG, F_("n:positive integer")},
+       { GNM_FUNC_HELP_NOTE, F_("The function computes the product of its distinct prime factors") },
+       { GNM_FUNC_HELP_EXAMPLES, "=NT_RADICAL(36)" },
+       { GNM_FUNC_HELP_SEEALSO, "NT_D,ITHPRIME,NT_SIGMA"},
+       { GNM_FUNC_HELP_END }
+};
+
+static void
+walk_for_radical (guint64 p, int v, void *data_)
+{
+       guint64 *data = data_;
+       *data *= p;
+}
+
+static GnmValue *
+gnumeric_radical (GnmFuncEvalInfo *ei, GnmValue const * const *args)
+{
+       guint64 rad = 1;
+       gnm_float n = gnm_floor (value_get_as_float (args[0]));
+
+       if (n < 1 || n > bit_max)
+               return value_new_error_NUM (ei->pos);
+
+       if (walk_factorization ((guint64)n, &rad, walk_for_radical))
+               return value_new_error (ei->pos, OUT_OF_BOUNDS);
+
+       return value_new_guint64 (rad);
+}
+
+/* ------------------------------------------------------------------------- */
+
 static GnmFuncHelp const help_nt_mu[] = {
        { GNM_FUNC_HELP_NAME, F_("NT_MU:Möbius mu function")},
        { GNM_FUNC_HELP_ARG, F_("n:positive integer")},
@@ -724,6 +757,9 @@ const GnmFuncDescriptor num_theory_functions[] = {
        {"nt_phi",   "f", help_phi,
         &gnumeric_phi,      NULL,
         GNM_FUNC_SIMPLE, GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC, GNM_FUNC_TEST_STATUS_EXHAUSTIVE },
+       {"nt_radical",   "f", help_radical,
+        &gnumeric_radical,      NULL,
+        GNM_FUNC_SIMPLE, GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC, GNM_FUNC_TEST_STATUS_BASIC },
        {"nt_d",     "f", help_d,
         &gnumeric_d,        NULL,
         GNM_FUNC_SIMPLE, GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC, GNM_FUNC_TEST_STATUS_EXHAUSTIVE },
diff --git a/plugins/fn-numtheory/plugin.xml.in b/plugins/fn-numtheory/plugin.xml.in
index fad6324b5..316e70885 100644
--- a/plugins/fn-numtheory/plugin.xml.in
+++ b/plugins/fn-numtheory/plugin.xml.in
@@ -18,6 +18,7 @@
                                <function name="nt_omega"/>
                                <function name="nt_phi"/>
                                <function name="nt_pi"/>
+                               <function name="nt_radical"/>
                                <function name="nt_sigma"/>
                                <function name="pfactor"/>
                        </functions>