Data commit

Task/M-bius-function/AWK/m-bius-function.awk

@@ -0,0 +1,46 @@
+# syntax: GAWK -f MOBIUS_FUNCTION.AWK
+# converted from Java
+BEGIN {
+    printf("first 199 terms of the mobius sequence:\n   ")
+    for (n=1; n<200; n++) {
+      printf("%3d",mobius(n))
+      if ((n+1) % 20 == 0) {
+        printf("\n")
+      }
+    }
+    exit(0)
+}
+function mobius(n,  i,j,mu_max) {
+    if (n in MU) {
+      return(MU[n])
+    }
+    mu_max = 1000000
+    for (i=0; i<mu_max; i++) { # populate array
+      MU[i] = 1
+    }
+    for (i=2; i<=int(sqrt(mu_max)); i++ ) {
+      if (MU[i] == 1) {
+        for (j=i; j<=mu_max; j+=i) { # for each factor found, swap + and -
+          MU[j] *= -i
+        }
+        for (j=i*i; j<=mu_max; j+=i*i) { # square factor = 0
+          MU[j] = 0
+        }
+      }
+    }
+    for (i=2; i<=mu_max; i++) {
+      if (MU[i] == i) {
+        MU[i] = 1
+      }
+      else if (MU[i] == -i) {
+        MU[i] = -1
+      }
+      else if (MU[i] < 0) {
+        MU[i] = 1
+      }
+      else if (MU[i] > 0) {
+        MU[i] = -1
+      }
+    }
+    return(MU[n])
+}