CDE

Task/Pi/C++/pi.cpp

@@ -0,0 +1,41 @@
+#include "gmp.h"
+
+void agm (const mpf_t in1, const mpf_t in2, mpf_t out1, mpf_t out2) {
+	mpf_add (out1, in1, in2);
+	mpf_div_ui (out1, out1, 2);
+	mpf_mul (out2, in1, in2);
+	mpf_sqrt (out2, out2);
+}
+
+int main (void) {
+	mpf_set_default_prec (300000);
+	mpf_t x0, y0, resA, resB, Z, var;
+
+	mpf_init_set_ui (x0, 1);
+	mpf_init_set_d (y0, 0.5);
+	mpf_sqrt (y0, y0);
+	mpf_init (resA);
+	mpf_init (resB);
+	mpf_init_set_d (Z, 0.25);
+	mpf_init (var);
+
+	int n = 1;
+	for(int i=0; i<8; i++){
+		agm(x0, y0, resA, resB);
+		mpf_sub(var, resA, x0);
+		mpf_mul(var, var, var);
+		mpf_mul_ui(var, var, n);
+		mpf_sub(Z, Z, var);
+		n += n;
+		agm(resA, resB, x0, y0);
+		mpf_sub(var, x0, resA);
+		mpf_mul(var, var, var);
+		mpf_mul_ui(var, var, n);
+		mpf_sub(Z, Z, var);
+		n += n;
+	}
+	mpf_mul(x0, x0, x0);
+	mpf_div(x0, x0, Z);
+	gmp_printf ("%.100000Ff\n", x0);
+	return 0;
+}

Task/Pi/D/pi-1.d

@@ -0,0 +1,38 @@
+import std.stdio, std.conv, std.string;
+
+struct PiDigits {
+    immutable uint nDigits;
+
+    int opApply(int delegate(ref string /*chunk of pi digit*/) dg){
+        // Maximum width for correct output, for type ulong.
+        enum size_t width = 9;
+
+        enum ulong scale = 10UL ^^ width;
+        enum ulong initDigit = 2UL * 10UL ^^ (width - 1);
+        enum string formatString = "%0" ~ text(width) ~ "d";
+
+        immutable size_t len = 10 * nDigits / 3;
+        auto arr = new ulong[len];
+        arr[] = initDigit;
+        ulong carry;
+
+        foreach (i; 0 .. nDigits / width) {
+            ulong sum;
+            foreach_reverse (j; 0 .. len) {
+                auto quo = sum * (j + 1) + scale * arr[j];
+                arr[j] = quo % (j*2 + 1);
+                sum = quo / (j*2 + 1);
+            }
+            auto yield = format(formatString, carry + sum/scale);
+            if (dg(yield))
+                break;
+            carry = sum % scale;
+        }
+        return 0;
+    }
+}
+
+void main() {
+    foreach (d; PiDigits(100))
+        writeln(d);
+}

Task/Pi/D/pi-2.d

@@ -0,0 +1,33 @@
+import std.stdio, std.bigint;
+
+void main() {
+    int ndigits = 0;
+    auto q = BigInt(1);
+    auto r = BigInt(0);
+    auto t = q;
+    auto k = q;
+    auto n = BigInt(3);
+    auto l = n;
+
+    bool first = true;
+    while (ndigits < 1_000) {
+        if (4 * q + r - t < n * t) {
+            write(n); ndigits++;
+            if (ndigits % 70 == 0) writeln();
+            if (first) { first = false; write('.'); }
+            auto nr = 10 * (r - n * t);
+            n = ((10 * (3 * q + r)) / t) - 10 * n;
+            q *= 10;
+            r = nr;
+        } else {
+            auto nr = (2    * q + r) * l;
+            auto nn = (q * (7 * k + 2) + r * l) / (t * l);
+            q *= k;
+            t *= l;
+            l += 2;
+            k++;
+            n = nn;
+            r = nr;
+        }
+    }
+}