#include <stdio.h>
-
-/*
- An interaction is a structure containing a "product" of other
- variables. The variables can be either string or numeric.
-
- Interaction is commutative. That means, that from a mathematical point of
- view, the order of the variables is irrelevant. However, for display
- purposes, and for matching with an interaction's value the order is
- pertinent.
-
- Therefore, when using these functions, make sure the orders of variables
- and values match when appropriate.
-*/
-
-
+/* Creates and returns an interaction. If V is nonnull, then the interaction
+ initially contains V, otherwise it is initially empty. */
struct interaction *
interaction_create (const struct variable *v)
{
- struct interaction *i = xmalloc (sizeof *i);
- i->vars = xmalloc (sizeof *i->vars);
- i->n_vars = 0;
+ struct interaction *iact = xmalloc (sizeof *iact);
+ iact->vars = xmalloc (sizeof *iact->vars);
+ iact->n_vars = 0;
if ( v )
{
- i->vars[0] = v;
- i->n_vars = 1;
+ iact->vars[0] = v;
+ iact->n_vars = 1;
}
- return i;
+ return iact;
}
-/* Deep copy an interaction */
+/* Returns a (deep) copy of interaction SRC. */
struct interaction *
-interaction_clone (const struct interaction *iact)
+interaction_clone (const struct interaction *src)
{
- int v;
- struct interaction *i = xmalloc (sizeof *i);
- i->vars = xcalloc (iact->n_vars, sizeof *i->vars);
- i->n_vars = iact->n_vars;
+ struct interaction *dst = xmalloc (sizeof *dst);
+ dst->vars = xmemdup (src->vars, src->n_vars * sizeof *src->vars);
+ dst->n_vars = src->n_vars;
+ return dst;
+}
- for (v = 0; v < iact->n_vars; ++v)
+/* Frees IACT. */
+void
+interaction_destroy (struct interaction *iact)
+{
+ if (iact)
{
- i->vars[v] = iact->vars[v];
+ free (iact->vars);
+ free (iact);
}
-
- return i;
}
+/* Appends variable V to IACT.
+ V must not already be in IACT. */
void
-interaction_destroy (struct interaction *i)
+interaction_add_variable (struct interaction *iact, const struct variable *v)
{
- if (NULL == i)
- return;
-
- free (i->vars);
- free (i);
+ iact->vars = xrealloc (iact->vars, (iact->n_vars + 1) * sizeof *iact->vars);
+ iact->vars[iact->n_vars++] = v;
}
-void
-interaction_add_variable (struct interaction *i, const struct variable *v)
+/* Returns true iff the variables in X->VARS are a proper subset of the
+ variables in Y->VARS. */
+bool
+interaction_is_proper_subset (const struct interaction *x,
+ const struct interaction *y)
{
- i->vars = xrealloc (i->vars, sizeof (*i->vars) * ++i->n_vars);
- i->vars[i->n_vars - 1] = v;
+ return x->n_vars >= y->n_vars && interaction_is_subset (x, y);
}
-
-/*
- Do the variables in X->VARS constitute a proper
- subset of the variables in Y->VARS?
- */
-bool
-interaction_is_proper_subset (const struct interaction *x, const struct interaction *y)
+static bool
+interaction_contains (const struct interaction *iact, const struct variable *v)
{
- if (x->n_vars >= y->n_vars)
- return false;
-
- return interaction_is_subset (x, y);
+ for (size_t i = 0; i < iact->n_vars; i++)
+ if (iact->vars[i] == v)
+ return true;
+ return false;
}
-/*
- Do the variables in X->VARS constitute a
- subset (proper or otherwise) of the variables in Y->VARS?
- */
+/* Returns true iff the variables in X->VARS are a subset (proper or otherwise)
+ of the variables in Y->VARS. */
bool
-interaction_is_subset (const struct interaction *x, const struct interaction *y)
+interaction_is_subset (const struct interaction *x,
+ const struct interaction *y)
{
- size_t i;
- size_t j;
- size_t n = 0;
-
- /* By definition, a subset cannot have more members than its superset */
if (x->n_vars > y->n_vars)
return false;
- /* Count the number of values which are members of both sets */
- for (i = 0; i < x->n_vars; i++)
- {
- for (j = 0; j < y->n_vars; j++)
- {
- if (x->vars [i] == y->vars [j])
- {
- n++;
- }
- }
- }
-
- /* If ALL the members of X were also found in Y, then this must be a subset */
- if (n >= x->n_vars)
- return true;
+ for (size_t i = 0; i < x->n_vars; i++)
+ if (!interaction_contains (y, x->vars[i]))
+ return false;
- return false;
+ return true;
}
-
-
-
+/* Prints the variables in IACT on stdout, for debugging purposes. */
void
-interaction_dump (const struct interaction *i)
+interaction_dump (const struct interaction *iact)
{
- int v = 0;
- if ( i->n_vars == 0)
+ if (iact->n_vars == 0)
+ printf ("(empty)\n");
+ else
{
- printf ("(empty)\n");
- return;
+ for (size_t v = 0; v < iact->n_vars; ++v)
+ {
+ printf ("%s", var_get_name (iact->vars[v]));
+ if (v + 1 < iact->n_vars)
+ printf (" * ");
+ }
+ printf ("\n");
}
- printf ("%s", var_get_name (i->vars[v]));
- for (v = 1; v < i->n_vars; ++v)
- printf (" * %s", var_get_name (i->vars[v]));
- printf ("\n");
}
/* Appends STR with a representation of the interaction, suitable for user
display.
- STR must have been initialised prior to calling this function.
-*/
+ STR must have been initialised prior to calling this function. */
void
interaction_to_string (const struct interaction *iact, struct string *str)
{
- int v = 0;
- if ( iact->n_vars == 0)
- return;
- ds_put_cstr (str, var_to_string (iact->vars[v]));
- for (v = 1; v < iact->n_vars; ++v)
+ for (size_t v = 0; v < iact->n_vars; ++v)
{
- ds_put_cstr (str, " * ");
ds_put_cstr (str, var_to_string (iact->vars[v]));
+ if (v + 1 < iact->n_vars)
+ ds_put_cstr (str, " * ");
}
}
+/* Returns a hash of the values in C given by variables in IACT, using BASE as
+ a basis for the hash. */
unsigned int
-interaction_case_hash (const struct interaction *iact, const struct ccase *c, unsigned int base)
+interaction_case_hash (const struct interaction *iact,
+ const struct ccase *c, unsigned int base)
{
- int i;
size_t hash = base;
- for (i = 0; i < iact->n_vars; ++i)
+ for (size_t i = 0; i < iact->n_vars; ++i)
{
const struct variable *var = iact->vars[i];
const union value *val = case_data (c, var);
return hash;
}
+/* Returns true iff all the variables in IACT have equal values in C1 and
+ C2. */
bool
-interaction_case_equal (const struct interaction *iact, const struct ccase *c1, const struct ccase *c2)
+interaction_case_equal (const struct interaction *iact,
+ const struct ccase *c1, const struct ccase *c2)
{
- int i;
- bool same = true;
-
- for (i = 0; i < iact->n_vars; ++i)
+ for (size_t i = 0; i < iact->n_vars; ++i)
{
const struct variable *var = iact->vars[i];
- if ( ! value_equal (case_data (c1, var), case_data (c2, var), var_get_width (var)))
- {
- same = false;
- break;
- }
+ if (!value_equal (case_data (c1, var), case_data (c2, var),
+ var_get_width (var)))
+ return false;
}
- return same;
+ return true;
}
-
+/* Returns a strcmp()-like comparison result for the variables in IACT and
+ their values in C1 and C2. */
int
-interaction_case_cmp_3way (const struct interaction *iact, const struct ccase *c1, const struct ccase *c2)
+interaction_case_cmp_3way (const struct interaction *iact,
+ const struct ccase *c1, const struct ccase *c2)
{
- int i;
- int result = 0;
-
- for (i = 0; i < iact->n_vars; ++i)
+ for (size_t i = 0; i < iact->n_vars; ++i)
{
const struct variable *var = iact->vars[i];
- result = value_compare_3way (case_data (c1, var), case_data (c2, var), var_get_width (var));
- if (result != 0)
- break;
+ int cmp = value_compare_3way (case_data (c1, var), case_data (c2, var),
+ var_get_width (var));
+ if (cmp)
+ return cmp;
}
- return result;
+ return 0;
}
-
+/* Returns true iff any of the variables in IACT have a missing value in C,
+ using EXCLUDE to decide which kinds of missing values to count. */
bool
-interaction_case_is_missing (const struct interaction *iact, const struct ccase *c, enum mv_class exclude)
+interaction_case_is_missing (const struct interaction *iact,
+ const struct ccase *c, enum mv_class exclude)
{
- int i;
- bool missing = false;
+ for (size_t i = 0; i < iact->n_vars; ++i)
+ if (var_is_value_missing (iact->vars[i], case_data (c, iact->vars[i]),
+ exclude))
+ return true;
- for (i = 0; i < iact->n_vars; ++i)
- {
- if ( var_is_value_missing (iact->vars[i], case_data (c, iact->vars[i]), exclude))
- {
- missing = true;
- break;
- }
- }
-
- return missing;
+ return false;
}
#include <stdbool.h>
#include "data/missing-values.h"
+struct ccase;
struct interaction;
-struct variable;
struct string;
+struct variable;
#include <stddef.h>
+
+/* An interaction is a structure containing a "product" of other variables.
+ The variables can be either string or numeric.
+
+ Interaction is commutative. That means, that from a mathematical point of
+ view, the order of the variables is irrelevant. However, for display
+ purposes, and for matching with an interaction's value the order is
+ pertinent. Therefore, when using these functions, make sure the orders of
+ variables and values match when appropriate.
+
+ Some functions for interactions will not work properly for interactions that
+ contain a given variable more than once, so this should be regarded as an
+ invariant. The functions to modify interactions don't check for this
+ invariant. */
struct interaction
-{
- size_t n_vars;
- const struct variable **vars;
-};
+ {
+ const struct variable **vars;
+ size_t n_vars;
+ };
-struct interaction * interaction_create (const struct variable *);
-struct interaction * interaction_clone (const struct interaction *);
+struct interaction *interaction_create (const struct variable *);
+struct interaction *interaction_clone (const struct interaction *);
void interaction_destroy (struct interaction *);
void interaction_add_variable (struct interaction *, const struct variable *);
void interaction_dump (const struct interaction *);
-void interaction_to_string (const struct interaction *iact, struct string *str);
-bool interaction_is_proper_subset (const struct interaction *x, const struct interaction *y);
-bool interaction_is_subset (const struct interaction *x, const struct interaction *y);
+void interaction_to_string (const struct interaction *, struct string *str);
+bool interaction_is_proper_subset (const struct interaction *,
+ const struct interaction *);
+bool interaction_is_subset (const struct interaction *,
+ const struct interaction *);
-struct ccase;
-unsigned int interaction_case_hash (const struct interaction *, const struct ccase *, unsigned int base);
-bool interaction_case_equal (const struct interaction *, const struct ccase *, const struct ccase *);
-bool interaction_case_is_missing (const struct interaction *, const struct ccase *, enum mv_class);
-int interaction_case_cmp_3way (const struct interaction *, const struct ccase *, const struct ccase *);
-
+unsigned int interaction_case_hash (const struct interaction *,
+ const struct ccase *, unsigned int base);
+bool interaction_case_equal (const struct interaction *, const struct ccase *,
+ const struct ccase *);
+bool interaction_case_is_missing (const struct interaction *,
+ const struct ccase *, enum mv_class);
+int interaction_case_cmp_3way (const struct interaction *,
+ const struct ccase *, const struct ccase *);
#endif
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