add isl_aff_pullback_multi_aff

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/doc/user.pod b/doc/user.pod
index f5ca6e6..426a943 100644 (file)
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -3480,6 +3480,17 @@ rounding towards zero.  C<isl_pw_aff_tdiv_r> computes the corresponding
 remainder.
 
        #include <isl/aff.h>
+       __isl_give isl_aff *isl_aff_pullback_multi_aff(
+               __isl_take isl_aff *aff,
+               __isl_take isl_multi_aff *ma);
+
+This function precomposes the input expression by the given
+C<isl_multi_aff>.  In other words, the C<isl_multi_aff> is plugged
+into the affine expression.
+Objects of type C<isl_multi_aff> are described in
+L</"Piecewise Multiple Quasi Affine Expressions">.
+
+       #include <isl/aff.h>
        __isl_give isl_basic_set *isl_aff_zero_basic_set(
                __isl_take isl_aff *aff);
        __isl_give isl_basic_set *isl_aff_neg_basic_set(

diff --git a/include/isl/aff.h b/include/isl/aff.h
index a84dd7e..d5527f9 100644 (file)
--- a/include/isl/aff.h
+++ b/include/isl/aff.h
@@ -101,6 +101,9 @@ __isl_give isl_aff *isl_aff_gist(__isl_take isl_aff *aff,
 __isl_give isl_aff *isl_aff_gist_params(__isl_take isl_aff *aff,
        __isl_take isl_set *context);
 
+__isl_give isl_aff *isl_aff_pullback_multi_aff(__isl_take isl_aff *aff,
+       __isl_take isl_multi_aff *ma);
+
 __isl_give isl_basic_set *isl_aff_zero_basic_set(__isl_take isl_aff *aff);
 __isl_give isl_basic_set *isl_aff_neg_basic_set(__isl_take isl_aff *aff);
 

diff --git a/isl_aff.c b/isl_aff.c
index 9174069..1117f4d 100644 (file)
--- a/isl_aff.c
+++ b/isl_aff.c
@@ -3488,6 +3488,70 @@ void isl_seq_preimage(isl_int *dst, isl_int *src,
        }
 }
 
+/* Compute the pullback of "aff" by the function represented by "ma".
+ * In other words, plug in "ma" in "aff".  The result is an affine expression
+ * defined over the domain space of "ma".
+ *
+ * If "aff" is represented by
+ *
+ *     (a(p) + b x + c(divs))/d
+ *
+ * and ma is represented by
+ *
+ *     x = D(p) + F(y) + G(divs')
+ *
+ * then the result is
+ *
+ *     (a(p) + b D(p) + b F(y) + b G(divs') + c(divs))/d
+ *
+ * The divs in the local space of the input are similarly adjusted
+ * through a call to isl_local_space_preimage_multi_aff.
+ */
+__isl_give isl_aff *isl_aff_pullback_multi_aff(__isl_take isl_aff *aff,
+       __isl_take isl_multi_aff *ma)
+{
+       isl_aff *res = NULL;
+       isl_local_space *ls;
+       int n_div_aff, n_div_ma;
+       isl_int f, c1, c2, g;
+
+       ma = isl_multi_aff_align_divs(ma);
+       if (!aff || !ma)
+               goto error;
+
+       n_div_aff = isl_aff_dim(aff, isl_dim_div);
+       n_div_ma = ma->n ? isl_aff_dim(ma->p[0], isl_dim_div) : 0;
+
+       ls = isl_aff_get_domain_local_space(aff);
+       ls = isl_local_space_preimage_multi_aff(ls, isl_multi_aff_copy(ma));
+       res = isl_aff_alloc(ls);
+       if (!res)
+               goto error;
+
+       isl_int_init(f);
+       isl_int_init(c1);
+       isl_int_init(c2);
+       isl_int_init(g);
+
+       isl_seq_preimage(res->v->el, aff->v->el, ma, n_div_ma, n_div_aff,
+                       f, c1, c2, g, 1);
+
+       isl_int_clear(f);
+       isl_int_clear(c1);
+       isl_int_clear(c2);
+       isl_int_clear(g);
+
+       isl_aff_free(aff);
+       isl_multi_aff_free(ma);
+       res = isl_aff_normalize(res);
+       return res;
+error:
+       isl_aff_free(aff);
+       isl_multi_aff_free(ma);
+       isl_aff_free(res);
+       return NULL;
+}
+
 /* Extend the local space of "dst" to include the divs
  * in the local space of "src".
  */