Merge branch 'master' of github.com:stclib/STC

1 files changed, 40 insertions, 35 deletions

diff --git a/misc/examples/spans/multidim.c b/misc/examples/spans/multidim.c
index 798a1126..ebc05a70 100644
--- a/misc/examples/spans/multidim.c
+++ b/misc/examples/spans/multidim.c
@@ -1,66 +1,71 @@
 // Example based on https://en.cppreference.com/w/cpp/container/mdspan
 #define i_val int
 #include <stc/cstack.h>
+#define i_implement
 #include <stc/cspan.h>
 #include <stdio.h>
 
 using_cspan3(ispan, int);
 
+void print2d(ispan2 ms2) {
+    for (int i=0; i < ms2.shape[0]; i++) {
+        for (int j=0; j < ms2.shape[1]; j++)
+            printf(" %3d", *cspan_at(&ms2, i, j));
+        puts("");
+    }
+}
+
+void print3d(ispan3 ms3) {
+    for (int i=0; i < ms3.shape[0]; i++) {
+        for (int j=0; j < ms3.shape[1]; j++) {
+            for (int k=0; k < ms3.shape[2]; k++)
+                printf(" %3d", *cspan_at(&ms3, i, j, k));
+            puts("");
+        }
+        puts("");
+    }
+}
+
 int main(void)
 {
     cstack_int v = c_init(cstack_int, {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24});
 
-    // View data as contiguous memory representing 24 ints
+    // Create 1d span from a compatibel container
     ispan ms1 = cspan_from(&v);
 
-    // View the same data as a 3D array 2 x 3 x 4
+    // Create a 3D mdspan 2 x 3 x 4
     ispan3 ms3 = cspan_md(v.data, 2, 3, 4);
 
     puts("ms3:");
-    for (int i=0; i != ms3.shape[0]; i++) {
-        for (int j=0; j != ms3.shape[1]; j++) {
-            for (int k=0; k != ms3.shape[2]; k++) {
-                printf(" %2d", *cspan_at(&ms3, i, j, k));
-            }
-            puts("");
-        }
-        puts("");
-    }
-    puts("ss3 = ms3[:, 1:3, 1:3]");
-    ispan3 ss3 = ms3;
-    ss3 = cspan_slice(ispan3, &ms3, {c_ALL}, {1,3}, {1,3});
+    print3d(ms3);
 
-    for (int i=0; i != ss3.shape[0]; i++) {
-        for (int j=0; j != ss3.shape[1]; j++) {
-            for (int k=0; k != ss3.shape[2]; k++) {
-                printf(" %2d", *cspan_at(&ss3, i, j, k));
-            }
-            puts("");
-        }
-        puts("");
-    }
+    // Take a slice of md3
+    ispan3 ss3 = cspan_slice(ispan3, &ms3, {c_ALL}, {1,3}, {1,3});
+    puts("ss3 = ms3[:, 1:3, 1:3]");
+    print3d(ss3);
 
     puts("Iterate ss3 flat:");
-    c_foreach (i, ispan3, ss3)
-        printf(" %d", *i.ref);
+    c_foreach (i, ispan3, ss3) printf(" %d", *i.ref);
     puts("");
 
-    ispan2 ms2 = cspan_submd3(&ms3, 0);
+    // submd3 span reduces rank depending on number of arguments
+    ispan2 ms2 = cspan_submd3(&ms3, 1);
 
-    // write data using 2D view
+    // Change data on the 2d subspan
     for (int i=0; i != ms2.shape[0]; i++)
         for (int j=0; j != ms2.shape[1]; j++)
-            *cspan_at(&ms2, i, j) = i*1000 + j;
+            *cspan_at(&ms2, i, j) = (i + 1)*100 + j;
+    
+    puts("\nms2 = ms3[1] with updated data:");    
+    print2d(ms2);
+    puts("");    
 
-    puts("\nview data as 1D view:");
-    for (int i=0; i != cspan_size(&ms1); i++)
-        printf(" %d", *cspan_at(&ms1, i));
+    puts("\nOriginal s1 span with updated data:");
+    c_foreach (i, ispan, ms1) printf(" %d", *i.ref);
     puts("");
 
-    puts("iterate subspan ms3[1]:");
-    ispan2 sub = cspan_submd3(&ms3, 1);
-    c_foreach (i, ispan2, sub)
-        printf(" %d", *i.ref);
+    puts("\nOriginal ms3 span with updated data:");
+    print3d(ms3);
     puts("");
 
     cstack_int_drop(&v);