Merge branch 'stclib:master' into modifiedHEADmodified

1 files changed, 76 insertions, 0 deletions

diff --git a/misc/examples/spans/multidim.c b/misc/examples/spans/multidim.c
new file mode 100644
index 00000000..70fda7e2
--- /dev/null
+++ b/misc/examples/spans/multidim.c
@@ -0,0 +1,76 @@
+// 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});
+
+    // Create 1d span from a compatibel container
+    ispan ms1 = cspan_from(&v);
+
+    // Create a 3D mdspan 2 x 3 x 4
+    ispan3 ms3 = cspan_md(v.data, 2, 3, 4);
+
+    puts("ms3:");
+    print3d(ms3);
+
+    // 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);
+    puts("");
+
+    // submd3 span reduces rank depending on number of arguments
+    ispan2 ms2 = cspan_submd3(&ms3, 1);
+
+    // 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 + 1)*100 + j;
+    
+    puts("\nms2 = ms3[1] with updated data:");    
+    print2d(ms2);
+    puts("");    
+
+    puts("\nOriginal s1 span with updated data:");
+    c_foreach (i, ispan, ms1) printf(" %d", *i.ref);
+    puts("");
+
+    puts("\nOriginal ms3 span with updated data:");
+    print3d(ms3);
+
+    puts("col = ms3[1, :, 2]");
+    ispan col = cspan_slice(ispan, &ms3, {1}, {c_ALL}, {2});
+    c_foreach (i, ispan, col) printf(" %d", *i.ref);
+    puts("");
+
+    cstack_int_drop(&v);
+}